Carrier Access Thermostat Thermidistat User Manual

Thermidistat™ Control  
Installation, Start-Up, and Operating Instructions  
NOTE: Read the entire instruction manual before starting the  
installation.  
This symbol indicates a change since the last issue.  
INDEX  
Page  
SAFETY CONSIDERATIONS.....................................................1  
INTRODUCTION..........................................................................1  
INSTALLATION CONSIDERATIONS.......................................1  
INSTALLATION........................................................................2-8  
Thermidistat Control Location .................................................2  
Set DIP Switches ......................................................................2  
Install Thermidistat Control ..................................................2-3  
Set Thermidistat Control Configuration ...............................3-7  
System Start-Up and Checkout.............................................7-8  
Final Settings ............................................................................8  
HUMIDITY CONTROL FEATURES.....................................8-11  
Humidification ..........................................................................8  
Dehumidification .................................................................9-10  
Vacation.............................................................................10-11  
OPERATIONAL INFORMATION.............................................11  
THERMIDISTAT CONTROL TROUBLESHOOTING ............11  
THERMIDISTAT CONTROL CONFIGURATION RECORD.12  
WIRING DIAGRAM..............See Thermidistat Wiring Diagrams  
A98426  
DEPTH (IN.)  
1-3/8  
HEIGHT (IN.)  
WIDTH (IN.)  
4-3/8  
7-3/8  
Fig. 1—Thermidistat Control  
INSTALLATION CONSIDERATIONS  
POWER  
Note that this control does not require batteries and is not "power  
stealing." It does require 24vac (R and C terminals) of the  
low-voltage transformer to be connected to it for proper operation.  
It will not operate without these 2 connections.  
MODELS  
There is a single programmable/non-programmable model for all  
applications. It can be configured for AC or HP, 1- or 2-speed  
compressor, and for dual fuel installations, allowing it to be used  
in place of all Carrier thermostats.  
SAFETY CONSIDERATIONS  
Read and follow manufacturer instructions carefully. Follow all  
local electrical codes during installation. All wiring must conform  
to local and national electrical codes. Improper wiring or installa-  
tion may damage Thermidistat Control.  
HUMIDIFY EQUIPMENT AND CONNECTIONS  
Recognize safety information. This is the safety-alert symbol  
When you see this symbol on the equipment and in the instruction  
manual, be alert to the potential for personal injury.  
.
The humidify output connects directly to 24vac operated humidi-  
fiers. No other connection or interlock is required. Any of several  
installer-selectable operating modes are available.  
Understand the signal words DANGER, WARNING, and CAU-  
TION. These words are used with the safety-alert symbol. DAN-  
GER identifies the most serious hazards which will result in severe  
personal injury or death. WARNING signifies a hazard which  
could result in personal injury or death. CAUTION is used to  
identify unsafe practices which would result in minor personal  
injury or product and property damage.  
DO NOT connect Furnace HUM terminal directly to  
Thermidistat HUM terminal. This will bypass furnace safety  
controls. See Low Voltage Wiring Daigrams and notes for  
proper connection.  
INTRODUCTION  
DEHUMIDIFY EQUIPMENT AND CONNECTIONS  
Carrier’s 7-day programmable/non-programmable Thermidistat  
The dehumidify output connects to the dehumidify input on  
variable-speed furnaces and fan coils. Additional dehumidification  
is done by controlling the compressor. A variety of operating  
modes are available.  
Control is a wall-mounted, low-voltage control which combines  
temperature and humidity control in a single attractive unit. An  
extension of Carrier’s proven line of thermostats, it provides  
separate set points for heating and cooling, and now adds humidi-  
fication and dehumidification. Different heating and cooling set  
points and times are programmable for 4 periods per day and 7  
days per week. The Thermidistat Control can also be field-  
configured as a non-programmable thermostat. When operating in  
the non-programmable configuration it will still have both tem-  
perature and humidity control. Humidify and dehumidify outputs  
provide direct control of humidity. Batteries are not used. During  
power loss an internal memory stores programs and settings for  
unlimited time, and the clock continues to run for at least 8 hr.  
OUTDOOR TEMPERATURE SENSOR  
Optimum performance is obtained when an outdoor temperature  
sensor is used with the Thermidistat Control. Plan installation so  
that 2 wires can be run from Thermidistat Control to an outdoor  
location, preferably on the north side of the house or refer to  
Installation Instructions included with the outdoor temperature  
sensor for simplified connection. Sensor can be mounted to  
outdoor unit and existing control wires may be used for its  
connection. Details are provided in sensor instructions.  
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.  
Book  
Tab misc. misc.  
1
4
PC 101  
Catalog No. 03TS-TA17  
Printed in U.S.A.  
Form TSTAT-23SI  
Pg 1  
8-99  
Replaces: TSTAT-19SI  
 
3. A2—for 2-speed air conditioner  
4. H2—for 2-speed heat pump  
5. dF—for 1-speed dual fuel  
6. d2—for 2-speed dual fuel  
press SET TIME/TEMP button once. The large display will now  
flash, indicating that up and down buttons now control available  
choices within that option. Each press of TIME/TEMP button  
switches between available option (small display) and available  
selections within each option (large display).  
7. HS—for 1-speed heat pump with Intelligent Heat Staging  
(3-stage auxiliary heat with 40FK, FK4C, or FV4A Series fan  
coils.)  
CONFIGURATION OPTIONS — SELECTION:  
Option 1—Anticipator Adjustment  
This adjustment controls sensitivity and cycle rate of Thermidistat  
Control. Higher numbers decrease sensitivity and slow cycle rate.  
Lower numbers increase sensitivity and cycle rate. However, a  
limiting feature will not allow more than 4 cycles per hr, regardless  
of setting. Anticipator values can range from 1 to 9. Factory  
default is 3. This default selection provides optimum performance  
in nearly all installations. Try it first. Do not change setting unless  
there is evidence of need to do so.  
When this identifier disappears, normal operation begins. The  
MODE control should be set to OFF and FAN control to AUTO,  
so equipment does not start until further configuration and check-  
out is completed.  
Step 4—Set Thermidistat Control Configuration  
Configuration options, like DIP switch settings, are intended to be  
selected at installation and normally are not modified by the  
homeowner. These options are not discussed in the homeowner’s  
manual and therefore must be made as part of the installation. A  
special procedure allows entry into the configuration mode. While  
in configuration mode, up to 17 selections can be made. A  
description of each selection and how to use the configuration  
mode follows.  
Unlike conventional anticipators, this setting is not determined by  
current draw. There is no need to measure, know, or compensate  
for current draw. There is also no droop with this Thermidistat  
Control. Regardless of setting and number of stages, both heating  
and cooling will control to their respective set points.  
TO ADJUST:  
CONFIGURATION OPTIONS — SUMMARY:  
Option 1—Anticipator adjustment  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." The upper small (COOL set  
point) display will be flashing 1. If not, use up and down  
buttons to move it to 1.  
Option 2—Clean filter timer adjustment  
Option 3—English/Metric selection  
2. Press SET TIME/TEMP button once to flash current selection  
of 1, 2, 3, 4, 5, 6, 7, 8, or 9 on large display. Factory default  
is 3.  
Option 4—Fan (G) ON with W selection  
Option 5—Variable-speed blower present selection  
Option 6—Cooling lockout below 55° selection  
3. Use up and down buttons to move between available choices.  
Option 7—Variable-speed super dehumidification selection (only  
available when variable-speed blower is used)  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
Option 8—Auxiliary heat lockout temperature setting (only avail-  
able when heat pump is used)  
Option 2—Clean Filter Timer  
Select hours of blower operation (heating, cooling, or fan) before  
CLEAN FILTER icon is displayed. With OFF selected, icon will  
never come on, disabling this feature. Time selection can range  
from 400 to 3600 hr by selecting numbers 1 through 9. (Time is  
400 X number selected.) Factory default is 2 (800 hr). Recom-  
mended selections are: disposable filter—400 to 800 hr, media  
filter—1200 to 1600 hr, or electronic air cleaner—1600 to 2400 hr  
of blower operation.  
Option 9—Intelligent Heat Staging selection (only available when  
single-speed heat pump is used)  
Option 10—Dual Fuel selection (only available when heat pump is  
used)  
Option 11—Balance point setting (only available when Dual Fuel  
is selected)  
Option 12—Defrost heat selection (only available when heat pump  
is used)  
TO SELECT OR ADJUST:  
Option 13—Room temperature offset adjustment  
Option 14—Heat/cool dead band adjustment  
Option 15—Enable Auto mode  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 2.  
2. Press SET TIME/TEMP button once to flash current selection  
of OF, 1, 2, 3, 4, 5, 6, 7, 8, or 9 on large display. Factory  
default is 2.  
Option 16—Enables Super Comfort Heat Mode  
Option 17—Non-Programmable selection  
TO ENTER CONFIGURATION MODE:  
3. Use up and down buttons to move between available choices.  
Press and hold FAN button for approximately 10 sec until COOL  
set point display indicates a flashing 1. The Thermidistat Control  
is now in configuration mode. It will automatically exit this mode  
if no button is pressed for 3 minutes. Pressing END button will exit  
configuration mode immediately.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
Option 3—English/Metric  
Select between Fahrenheit and Celsius operation. Factory default  
is Fahrenheit.  
WHILE IN CONFIGURATION MODE:  
The upper small (COOL set point) display indicates selected  
option number and large display indicates selection made within  
that option. One of these will be flashing. The up and down buttons  
are used both to move between available options and to make  
selection for each option. When option number (small display) is  
flashing, up and down buttons adjust it, moving between available  
option numbers. After desired option number has been selected,  
TO SELECT OR ADJUST:  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 3.  
2. Press SET TIME/TEMP button once to flash current selection  
of F or C. Factory default is F.  
3
 
3. Use up and down buttons to move between F and C on large  
display.  
call for cooling. Not all products with ICM blowers have this  
feature. Check Installation Instructions for ICM air handler used.  
Select OF for normal operation (Y and G supplied on a cooling  
call). Select ON for super dehumidification (Y with no G on a  
dehumidify only call). Factory default is OF (off).  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
TO SELECT:  
Option 4—Fan (G) On With W  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 7.  
This selection determines whether fan (G) output is to be ON or  
OFF when any W (furnace or strip heat) output is ON. Most  
furnaces and fan coils manage their own blowers and do not  
require separate G signal. For these applications, select OFF. Some  
auxiliary heaters require separate G signal to turn on blower. In  
this case, select ON. Factory default is OF (off).  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up or down buttons to alternate between OF and ON on  
large display. Factory default is OF.  
TO SELECT:  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 4.  
Option 8—Auxiliary Heat Lockout Setting  
2. Press SET TIME/TEMP button once to flash large display.  
This option requires prior selection of heat pump (DIP switch 1--  
ON). It allows selection of an outdoor temperature of 5o through  
55°F. (or equivalent values in C), or OF (off). Auxiliary heat  
(furnace in Dual Fuel applications) is prevented from operating for  
outdoor temperatures above selected temperature. If OF (off) is  
selected, auxiliary heat (furnace if Dual Fuel) operation is allowed  
at all outdoor temperatures. If selected, emergency heat (EHEAT)  
overrides this feature. Factory default is OF (off). This setting can  
only be equal to or above the setting choice made for Option 11.  
Moving this setting lower may ’push’ Option 11 setting down-  
ward.  
3. Use up or down buttons to alternate between OF and ON on  
large display. Factory default is OF.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
Option 5—Variable-Speed (ICM) Blower  
If furnace or fan coil contains a variable-speed (ICM) blower, set  
this option to ON. For normal (PSC) blowers, set to OF. This  
selection enables system to use special features available only in  
units with an ICM blower. Factory default is OF (off).  
TO SELECT:  
TO SELECT:  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 5.  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 8.  
2. Press SET TIME/TEMP button once to flash large display.  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up or down buttons to alternate between OF and ON on  
large display. Factory default is OF.  
3. Use up or down buttons to move between OF, 5, 10, 15, 20,  
25, 30, 35, 40, 45, 50, or 55 on large display. Factory default  
is OF.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
Option 6—Cooling Lockout Below 55°F  
This option disables cooling when outdoor temperature is below  
55°F. It requires an outdoor temperature sensor. Set to OF to allow  
cooling below 55°F. Set to ON to prevent cooling below 55°F.  
Factory default is OF (off).  
Option 9—Intelligent Heat Staging  
This option requires prior selection of single-speed heat pump  
(DIP switch 1—ON, DIP switch 2—OF). It provides 3 stages of  
electric heat from W1 and W2 by sequencing W1 only, then W2  
only, then both W1 and W2. See FK or FV Series Fan Coil  
Installation Instructions for further information. For 3-stage heat,  
select ON. For normal 1- or 2-stage heat, select OF. Factory  
default is OF (off).  
TO SELECT:  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 6.  
2. Press SET TIME/TEMP button once to flash large display.  
TO SELECT:  
3. Use up or down buttons to alternate between OF and ON on  
large display. Factory default is OF.  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 9.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up or down buttons to alternate between OF and ON on  
large display. Factory default is OF.  
Option 7—Variable-Speed Superdehumidify  
This option requires prior selection of variable-speed (ICM)  
blower (Option 5). When selected, this option operates blower at  
further reduced airflow from that of normal dehumidification when  
there is a dehumidification demand without a cooling demand,  
achieving maximum humidity removal with minimum cooling. It  
is done by supplying blower with a Y signal and no G signal on a  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
4
 
Option 10—Dual Fuel Equipment  
to operate. This can be somewhat complicated to determine and it  
involves knowing the cost of gas and electricity, as well as the  
efficiency of the furnace and heat pump. For the most economical  
operation, the heat pump should operate above this temperature  
(assuming it has sufficient capacity), and the furnace should  
operate below this temperature.  
All dual fuel installations must be equipped with a high  
pressure switch to turn off compressor under a high indoor  
coil pressure condition.  
COMFORT BALANCE TEMPERATURE:  
The high pressure switch protects compressor and indoor coil from  
overpressure which would occur if a failure or wiring error  
resulted in the heat pump and furnace operating at the same time.  
High Pressure Switch Kit includes required switch and instructions  
for proper operation. For all dual fuel installations, outdoor  
temperature sensor must be attached. If not, E3 error message will  
appear. See "Error Codes."  
When the heat pump is operating below this point, the indoor  
supply air feels uncomfortable (i.e. too cool). This is purely  
subjective and will depend on the homeowner’s idea of comfort.  
Below this temperature, the gas furnace should operate in order to  
satisfy the desire of indoor comfort.  
TO SELECT:  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 11.  
This option requires prior selection of heat pump (DIP switch  
1—ON), and must be selected in dual fuel installations. It prevents  
simultaneous operation of both furnace and heat pump, and  
prevents direct transition from heat pump to furnace operation.  
When system is dual fuel (heat pump and furnace), set to ON.  
When system contains fan coil, set to OF. Factory default is OF  
(off).  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up or down buttons to move between OF, 5, 10, 15, 20,  
25, 30, 35, 40, 45, 50, or 55 on large display. Factory default  
is OF.  
TO SELECT:  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 10.  
Option 12—Defrost Heat Select  
2. Press SET TIME/TEMP button once to flash large display.  
This option allows installer to select the amount of heat provided  
by Thermidistat Control during a heat pump defrost cycle. This can  
be very helpful in maintaining a comfortable leaving air tempera-  
ture during defrost. The Thermidistat Control senses when defrost  
is in progress by monitoring voltage placed on the O line by the  
heat pump while defrosting. It responds by turning on selected  
combination of W1 and W2 during defrost. Note that this is very  
different from the operation of an ordinary thermostat, which  
cannot sense defrost in progress and only turns on its W outputs in  
response to a temperature demand. Combinations of W1 and W2  
are selected via the following:  
3. Use up or down buttons to alternate between OF and ON on  
large display. Factory default is OF.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
Option 11—Balance Point Setting  
This option is for dual fuel installations only. It requires prior  
selection of heat pump (DIP switch 1 -- ON) and dual fuel  
equipment (Option 10 -- ON). It allows selection of an outdoor  
temperature of 5oF. through 55oF. (or equivalent values in C.), or  
OF (off). Heat pump is prevented from operating for outdoor  
temperatures below selected temperature. If OF (off) is selected,  
heat pump operation is allowed at all outdoor temperatures.  
Factory default is OF (off). This setting can only be equal to or  
below the setting choice made for Option 8. Moving the setting  
higher may ’push’ Option 8 setting upward.  
Table 1—W1 / W2 Outputs  
SELECTION  
0
DEFINITION  
Neither W1 or W2 is turned on.  
This is factory default.  
1
2
Only W1 is turned on.  
Both W1 and W2 turned on.  
If the outdoor temperature is above the "balance point setting", the  
heat pump will energize first to try to satisfy the indoor tempera-  
ture demand. If the heat pump does not make a sufficient  
improvement within a reasonable time period (i.e. 15 minutes),  
then the gas furnace will come on to satisfy the indoor temperature  
demand. If the outdoor temperature is below the "balance point  
setting" the heat pump will not be allowed to operate (i.e. locked  
out), and the gas furnace will be used to satisfy the indoor  
temperature.  
There are three separate concepts which are related to selecting the  
final "balance point setting". Read each of the following carefully  
to determine the best "balance point setting" in a dual fuel  
installation:  
Only W2 turned on (available  
only if 3-stage heat is selected).  
3
The selection procedure is given below. If 0 is selected, operation  
is like that of an ordinary thermostat, and a wire is required  
between W2 of outdoor unit and a selected W on indoor unit.  
When selection 1, 2, or 3 is made, no wire should be connected  
from outdoor W2 because this connection may override selection  
made. Obviously the heater must be in 2 sections, and fan coil  
jumper must be removed between W1 and W2 for there to be a  
difference between selections 1, 2, and 3. For most heaters, W1 is  
lower wattage heater, and W2 is higher, although some have equal  
elements for W1 and W2. Consult fan coil/heater combination for  
the actual wattage connected to each of W1 and W2.  
CAPACITY BALANCE TEMPERATURE:  
This is the point where the heat pump cannot provide sufficient  
capacity to keep up with the indoor temperature demand because  
of declining outdoor temperature. At or below this point, the  
furnace is needed to maintain proper indoor temperature.  
In dual fuel applications, above selection choices apply and can be  
used to select low or high heat if furnace is 2 stage. W1 will  
produce low heat. W1 and W2 together produce high heat. This  
option provides no value with single-stage furnaces because only  
1 value of heat is available.  
ECONOMIC BALANCE TEMPERATURE:  
Above this point, the heat pump is the most cost efficient to  
operate, and below this point, the furnace is the most cost efficient  
The selection choices guarantee selected outputs will be on during  
defrost. If room temperature demand requires additional heat, it  
5
 
will be supplied, resulting in additional outputs being turned on. If  
room overheats, specified outputs will not turn off, guaranteeing a  
sufficiently warm leaving air temperature during defrost. Tempera-  
ture overshoot during defrost can occur, but is almost never  
noticeable because of the short duration of the defrost cycle (4  
minutes typical, 10 minutes maximum).  
that it cannot switch between heat and cool without a 20 minute  
"off" time between the 2 operations. Specifically, to switch from 1  
mode to the other, there must be no demand for the old mode and  
a demand for the new mode, and this must exist continually for 20  
minutes before transition to the new mode will occur.  
TO SELECT:  
An additional feature of Thermidistat Control defrost is that it  
always allows defrost cycle to run to completion. The Thermidistat  
Control leaves the Y output on as long as outdoor unit holds  
voltage on the O line, even if it is satisfied. This prevents  
premature termination of defrost cycles, which occur with normal  
thermostats.  
1. Enter configuration mode if not already there. See Step 4 "To  
enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 14.  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up or down buttons to move between 0, 1, 2, 3, 4, 5, or 6  
on large display. Factory default is 2.  
TO SELECT:  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 12.  
Option 15—Enable Auto Mode  
2. Press SET TIME/TEMP button once to flash large display.  
This option allows the installer to enable or disable AUTO mode  
(automatic changeover between heat and cool). When disabled,  
AUTO icon does not appear when successive presses of MODE  
button are used to move between OFF, HEAT, COOL, and  
EHEAT (in heat pump systems). Factory default is ON (AUTO  
enabled).  
3. Use up or down buttons to move between 0, 1, 2, or 3 (if  
available) on large display. See Table 1 for effect of these  
choices. Factory default is 0.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
TO SELECT:  
Option 13—Room Temperature Offset Adjust  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 15.  
This option allows calibration (or deliberate miscalibration) of  
room temperature sensor. There are various reasons why home-  
owners may want to have displayed temperature adjusted to a  
higher or lower value. The selected number is number of degrees  
farhenheit, plus or minus, which will be added to actual tempera-  
ture. The numbers can range between -5 and +5. Factory default is  
0. This adjusted value will be used as actual temperature for both  
display and control action. For example, if 2 is selected, 72°F  
actual will read 74°F. If set point is 72°F, the room will control to  
an actual temperature of 70°F which will be displayed and acted  
upon as if it were 72°F. The effect is that a positive number  
selection will make the room temperature lower and vice versa.  
The Thermidistat Control is calibrated within an accuracy of plus  
or minus 1°F when shipped from the factory, so this adjustment  
will provide the best accuracy when set to 0.  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up and down buttons to move between OF and ON on  
large display. Factory default is ON (AUTO enabled).  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
Option 16—Enable Super Comfort Heat Mode  
This option requires prior ON selection of heat pump (DIP switch  
No. 1) and Configuration Option No. 5 (Select Variable-Speed  
Blower). Super Comfort Heat mode is part of the Comfort Heat  
Pump system, which comprises a selected combination of Ther-  
midistat Control, variable speed Fan Coil, and 3-stage electric  
heater to provide superior heat pump leaving air temperatures  
under all conditions. This option selection modifies heat pump  
blower and auxiliary heat operation to contribute to comfortable  
leaving air temperature. Specifically, this selection provides:  
TO SELECT:  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 13.  
Reduced heat pump airflow for outdoor temperatures between  
12° and 40°F.  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up or down buttons to move between -5, -4, -3, -2, -1, 0,  
1, 2, 3, 4, or 5 on large display. Factory default is 0.  
At least 1 stage of electric heat ON for all heating below 12°F.  
While outdoor air temperature is between 12°F and 40°F, the  
Thermidistat Control removes the G signal during heat pump  
heating. The 40FK, FK4C, or FV4A Variable-Speed Fan Coils  
respond by reducing their airflow in the absence of the G signal,  
raising leaving air temperature. For any heating demand below  
12°F, G and W/W1 are turned ON, assuring at least 1 stage of  
electric heat is on, and also increasing leaving air temperature.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
Option 14—Heat/Cool Dead Band Adjustment  
This option selects the minimum difference between heat and cool  
set points. A larger difference saves energy and a smaller differ-  
ence decreases temperature difference between heating and cool-  
ing. Factory default is 2, which means cooling set point must be a  
minimum of 2° above heating set point. An attempt to move them  
closer will result in one "pushing" the other to maintain the  
required difference.  
As part of the Comfort Heat pump system, Configuration Option  
No. 9 (Intelligent Heat Staging) should also be set to ON if the heat  
pump is single stage and a 3-stage heater is present.  
TO SELECT:  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 16.  
Depending on set points, moving dead band closer than 2° may  
result in regular cycling between heat and cool when AUTO mode  
is selected. However, this cycling cannot occur more often than 1  
transition every 20 minutes. The system has a built-in requirement  
2. Press SET TIME/TEMP button once to flash large display.  
6
 
A99059  
Fig. 2—Programmable/Non-Programmable Keypad Labels  
3. Use up and down buttons to move between OF and ON on  
large display. Factory default is OF.  
1. Enter configuration mode if not already there. See Step 4 "To  
Enter Configuration Mode." Use up and down buttons to make  
small (now flashing) display indicate 17.  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
2. Press SET TIME/TEMP button once to flash large display.  
3. Use up and down buttons to move between ON and OF on  
large display. Factory default is OF.  
Option 17—Enable Non-Programmable Operation  
4. Press SET TIME/TEMP button again to flash upper small  
display for selection of another option, or press END to exit  
configuration mode.  
This option converts the programmable Thermidistat Control to a  
non-programmable control for those users who do not want  
programmability. The clock is retained, but the days of the week  
and the daily schedules have been eliminated, making it operate as  
if HOLD were permanently ON. Some of the buttons (used in  
programming only and now not needed) are redefined to simplify  
the non-programmable operation. To match these redefined but-  
tons, a new keypad label, included with the Thermidistat, must be  
placed over the original keypad label. Fig. 2 shows both the  
original keypad label and the non-programmable keypad label.  
When this option is selected, the new keypad label must be applied  
over (or in place of) the original. Because these adhesive-backed  
keypad labels are not designed to be removed, this conversion  
should be considered permanent. Once the change to non-  
programmable operation is done, a procedure is not provided to  
easily change it back. Should this change be needed, it is best to  
trade the Thermidistat for one which has not been converted.  
REDEFINITION OF BUTTONS  
Fig. 2 shows the original (programmable) button labels on the left  
and the redefined (non-programmable) buttons on the right. In the  
figure, the buttons are numbered for easy reference. They are not  
numbered on the actual product. Six of the buttons (numbers 1  
through 5 and 9) have been redefined.  
Button 3 originally alternated between time, cool set point, and  
heat set point with each press. Now, button 1 selects the cool set  
point, button 2 selects the heat set point, and button 3 selects time,  
now used only to set the clock. Note that the days of the week are  
gone.  
Button 5 used to alternate between humidify and dehumidify. Now  
button 4 selects dehumidify and button 5 selects humidify.  
Both programmable and non-programmable versions of the Ho-  
meowner’s Manual are available. Be sure to leave only the correct  
version of the Homeowner’s Manual with the homeowner.  
Button 9 now loses the HOLD label, making it END only. This  
button is only used to END the humidity screen and the configu-  
ration mode.  
These changes both simplify operation for the homeowner and find  
use for the buttons which are no longer needed when programma-  
bility is removed.  
Once it has been determined that a particular installation is to be  
made non-programmable, the only changes required are:  
Attach non-programmable keypad label over original program-  
mable one.  
Step 5—System Start-Up and Checkout  
The Thermidistat Control is designed with a built-in installer test  
capability. It allows easy operation of equipment without delays or  
set point adjustments to force heating or cooling.  
Attach non-programmable start-up sticker instructions to back  
of door.  
Set Configuration Option No. 17 to ON.  
To enable installer test mode, move DIP switch No. 4 to ON  
position. To access this switch, open case as described in Step 2.  
Use the corner of a small screwdriver to slide switch No. 4 to ON  
position.  
Leave non-programmable homeowner’s manual with home-  
owner.  
To attach the provided non-programmable keypad label, carefully  
peel off its backing and apply it over the original keypad label.  
PLEASE HEED: Once the new keypad label makes contact, it will  
stick firmly in place and adjustments cannot be made. CARE-  
FULLY locate an edge of the keypad label, making sure its  
position and orientation are correct. Then, from the attached edge,  
smooth the rest of the keypad label over the original. Make sure the  
new keypad label does not interfere with the motion of the buttons  
which it surrounds.  
While in installer setup mode, clock will display "InSt," FAN  
button will control fan, and MODE button will control heating and  
cooling.  
TO TEST FAN:  
Fan button switches FAN icon between AUTO and ON. While ON  
is displayed, G output will be on, turning fan on. Allow up to 10  
sec after button is pressed for fan to turn on and off. On some fan  
coils, fan continues to operate for 90 sec after G signal is removed.  
TO SELECT:  
7
 
Table 2—Equipment Outputs  
1-SPEED AC  
2-SPEED AC  
Y1, G  
1-SPEED HP  
Y, G, O  
Y, G, O  
Y, G  
2-SPEED HP  
Y1, G, O  
Y1, Y2, G, O  
Y1, G  
Cool—0 to 2 minutes  
Cool—2 to 4 minutes  
Heat—0 to 2 minutes  
Heat—2 to 4 minutes  
Eheat—0 to 2 minutes  
Eheat—2 to 4 minutes  
* Two-stage heat not available  
Y, G  
Y, G  
W1  
Y1, Y2, G  
W1  
W1, W2  
---  
W1, W2  
---  
Y, G  
Y1, Y2, G  
W1  
W1  
---  
---  
W1, W2†  
W1*  
NOTE: For Y—use terminal Y/Y2, for Y1—use terminal Y1/W2, for W2—use terminal O/W2,  
for O—use terminal O/W2, for W1—use terminal W/W1, for W2†, use terminal Y1/W2  
TO TEST COOLING AND DEHUMIDIFICATION:  
Table 3—Energy Star Default Schedule  
Press MODE button until COOL icon turns on. Cooling begins  
within 10 sec and remains on for 4 minutes. If system is 2-speed,  
low speed comes on for first 2 minutes, followed by high speed for  
second 2 minutes. At the end of 4-minute run, cooling stops, and  
MODE reverts back to OFF. At any time during 4-minute run time,  
cooling may be turned off by pressing MODE button until OFF  
appears. While cooling is on, successive presses of HUMIDITY  
button turn dehumidify output on and off. While this output is  
active, "dh" appears in cool set point display. Equipment outputs  
for different equipment types are listed in Table 2.  
SCHEDULE  
Wake 6:00 AM  
Day 8:00 AM  
HEAT  
68°F  
60°F  
68°F  
60°F  
COOL  
78°F  
85°F  
78°F  
82°F  
Evening 5:00 PM  
Sleep 10:00 PM  
The FAN button may be used to select between AUTO (fan on  
only with equipment) and FAN (fan on continuously) fan modes.  
For further information on temperature selection and program-  
ming, refer to Homeowner’s Guide.  
TO TEST PRIMARY HEATING AND HUMIDIFICATION:  
HUMIDITY CONTROL FEATURES  
The various humidity control features of the Thermidistat Control  
Press MODE button until HEAT icon turns on. Primary heating  
begins within 10 sec and remains on for 4 minutes. This will be  
furnace or electric heat in AC system and heat pump heating in  
heat pump system. If system has 2 stages of primary heat, first  
stage will be on for 2 minutes followed by second stage for 2  
minutes. At the end of 4-minute run, heating stops, and MODE  
reverts back to OFF. At any time during 4-minute run time, heating  
may be turned off by pressing MODE button until OFF appears.  
While heating is on, successive presses of HUMIDITY button turn  
humidify output on and off. While this output is active, "hu"  
appears in heat set point display. Equipment outputs for different  
equipment types are listed in Table 2.  
are explained below. They are grouped into 2 sections: humidifi-  
cation and dehumidification. At the end of each section, instruc-  
tions on how to select each feature are given.  
HUMIDIFICATION  
The Thermidistat Control directly connects to a standard 24-vac  
humidifier to control humidification in the home. A humidify set  
point between 10 and 45 percent relative humidity is selected by  
the homeowner, or all humidification can be turned off. When  
humidity in home drops below set point, humidifier will be turned  
on to raise humidity level. Humidification can only occur in  
heating mode (HEAT or AUTO/HEAT). Five different humidifi-  
cation selections are available and are described below.  
TO TEST AUXILIARY HEATING:  
1. Normal Humidify  
Auxiliary heating only exists in heat pump systems. To test, press  
MODE button until EHEAT icon turns on. This will be electric  
heat in standard heat pump systems and furnace in dual fuel  
systems. Auxiliary heating begins within 10 sec and remains on for  
4 minutes. If there are 2 stages of auxiliary heat, first stage comes  
on for 2 minutes followed by second stage for 2 minutes. At the  
end of 4-minute run, heating stops and MODE reverts back to  
OFF. At any time during 4-minute run time, heating may be turned  
off by pressing MODE button until OFF appears. Actual outputs  
for different equipment types are listed in Table 2.  
In normal humidify, humidifier will be on if there is a  
humidity demand and any heating equipment is on. This will  
include furnace, heat pump, or auxiliary heat. In heat pump  
applications, this is an improvement over using an external  
humidistat, which only supplies humidity when auxiliary heat  
is on.  
2. Fan Humidify  
This configuration allows a humidify demand to turn on fan  
and humidifier together, even if there is no heat demand. It is  
particularly useful when the furnace is oversized, resulting in  
short heating cycles. It allows the humidifier to run longer,  
supplying more humidity to the home. Note that fan hours will  
increase, using more electricity. Also, the humidifier delivers  
less moisture to cooler air than it does to heated air.  
3. Auto Humidify  
Step 6—Final Settings  
Be sure to return DIP switch No. 4 back to OFF position to exit  
installer setup mode. Assuming system is to be left in operation  
after installation is complete, use MODE button to select between  
HEAT, COOL, or AUTO to provide desired operation of heating,  
cooling, or both.  
This feature is designed to eliminate the problem of sweating  
windows in very cold weather. When selected, the set point is  
automatically reduced by 1 percent for every drop of 2°F in  
outdoor temperature between 50°F and 0°F. The set point may  
be changed at any time, and it will continue to track outdoor  
temperature from the new set point and current outdoor  
temperature. The adjusted set point range is still limited to  
between 10 and 45 percent relative humidity. To use this  
feature, an outdoor temperature sensor MUST be attached. If  
not, E3 error message will be displayed.  
The default set points and programmed schedule conform to the  
Energy Star® requirements of the U.S. Department of Energy for  
both heating and cooling. These provide energy saving tempera-  
ture settings. Refer to Table 3.  
If programmed schedule is to be used, make sure HOLD icon is  
off. This feature is turned on and off by HOLD button.  
If fixed temperatures are desired, use HOLD button to turn on  
HOLD icon. This will maintain set points, not allowing them to  
change with programmed schedule.  
8
 
Table 4—Humidification Selections  
HUMIDIFY SET POINT  
DISPLAY  
SELECTION  
MODE DISPLAY  
FAN DISPLAY  
Normal Humidify  
Fan Humidify  
Auto Humidify  
Auto and Fan  
Humidify Off  
Blank  
Blank  
AUTO  
AUTO  
Blank  
Blank  
FAN  
Humidify Set Point Value  
Humidify Set Point Value  
Humidify Set Point Value  
Humidify Set Point Value  
OF  
Blank  
FAN  
Blank  
4. Auto and Fan Humidify  
The cool to dehumidify selection tells the system to operate  
the compressor, within limits, when there is a dehumidify  
demand even if there is no cooling demand. The limits are that  
the system may overcool up to 3°, but no more, while  
attempting to satisfy a dehumidify demand. Within this 3°  
range, there is an additional balance between overcooling and  
humidity satisfaction. When overcooling must occur, the  
dehumidify set point is adjusted upward by 2 percent per  
degree of overcooling. For example, a cooling set point of  
76°F and a dehumidify set point of 60 percent is equivalent to  
a cooling set point of 75°F and a dehumidify set point of 62  
percent. This dehumidify set point change is internal to the  
Thermidistat Control and is not shown on the display.  
The 2 choices of AUTO and FAN can be selected together.  
This provides both functions simultaneously.  
5. Humidify Off  
The humidify function can be turned off completely. This does  
not require changing existing set points.  
To Select Humidification (Between NORMAL, FAN, AUTO,  
FAN and AUTO, or OFF) (See Table 4.)  
Press HUMIDITY button to bring up humidity select screen. It is  
indicated by "hu" or "dhu" in clock display. Successive presses  
will change between "hu" and "dhu" in clock display. Select "hu"  
for humidity functions. The large display shows actual humidity  
level. The smaller display (in heat set point location) shows  
humidity set point (Humidify Set Point) or OF (off). When  
Humidity Set Point value is displayed, its value can be changed  
with up and down buttons. Successive presses of MODE button  
will move between 5 choices described above and each will be  
indicated as shown in Table 4.  
During cool-to-dehumidify demand, the compressor runs a  
maximum of 10 minutes on, followed by 10 minutes off.  
When the compressor turns off, the fan (G output) is also  
turned off immediately. The immediate fan shutoff prevents  
re-evaporation of water on the coil, improving dehumidifica-  
tion. If fan is set to continuous, the G (fan on) signal is  
removed for 5 minutes starting when compressor turns off.  
To exit humidity select screen, press END button.  
In most furnaces and fan coils, the blower operates for 90 sec  
after both Y and G disappear. This 90-sec delay should be  
removed, if possible, for maximum dehumidification perfor-  
mance. Consult furnace or fan coil Installation Instructions to  
see if delay can be disabled.  
Additional Humidify Comments  
The humidifier is actually turned on when humidity is 2 percent  
below set point and turned off when it reaches 2 percent above set  
point. This built-in hysteresis prevents humidify output from  
toggling on and off when humidity level is near set point.  
3. Dehumidify Off  
The vacation mode provides some additional humidification func-  
tions. These are specially designed to provide protection for an  
unoccupied home while simultaneously minimizing energy use.  
Refer to "Vacation" section for additional information.  
Dehumidification can be turned off completely. This can be  
done without changing existing set points.  
To Select Dehumidification (Between NORMAL, COOL TO,  
and OFF)  
DEHUMIDIFICATION  
Press HUMIDITY button to bring up humidity selections. Succes-  
sive presses will show "hu" or "dhu" in clock display. Select "dhu"  
for dehumidify selections. The large display shows actual humidity  
level. The smaller display (in cool set point location) shows  
dehumidify set point (DSP) or OF (off). When DSP value is  
displayed, its value can be changed with up and down buttons.  
Successive presses of MODE button moves between 3 choices  
above and each will be indicated as in Table 5.  
Dehumidification is done only during cooling. Depending on type  
of equipment used, compressor speed, blower speed, set point  
adjustment, and equipment cycling are modified to provide added  
dehumidification. A dehumidification set point (separate from  
humidification set point) is available to the homeowner. It can  
range from 50 to 90 percent relative humidity. When actual  
humidity is higher than set point, a dehumidification demand  
exists. The Thermidistat Control responds by activating its dehu-  
midify output. It may also control the compressor and blower,  
depending on equipment type and dehumidify selection choice.  
The 3 available selections are described below.  
Superdehumidify (With Cool to Dehumidify)  
This selection only affects cool-to-dehumidify operation. It is part  
of the installer setup (see Configuration Option No. 7) and must be  
made by installer. The Homeowner’s Guide does not cover this  
selection. A requirement is the use of a variable-speed indoor unit  
with superdehumidify capability. During cool-to-dehumidify call,  
it provides maximum dehumidification by reducing airflow to a  
minimum. The actual superdehumidify command from Thermidis-  
tat Control to the indoor unit is a Y signal without a G signal in  
addition to dehumidify signal. The indoor unit responds to this  
combination by reducing the airflow to a minimum. All other  
characteristics of cool to dehumidify are the same.  
The amount of extra dehumidification available is very dependent  
on the type of equipment in the home. Without a variable-speed  
blower, the system’s ability to adjust dehumidification is very  
limited.  
1. Normal Dehumidify Operation  
When normal dehumidify is selected, the compressor will not  
turn on without a cooling demand. If dehumidify demand  
exists while cooling, dehumidify output will also be active  
(24vac removed). This output commands variable-speed  
blowers to reduce their airflow, which improves water re-  
moval from the cooled air.  
Additional Dehumidify Comments  
Dehumidification can be enhanced (with some efficiency loss) by  
turning blower off immediately at the end of each cooling cycle  
(eliminating normal 90 sec blower off delay). Where maximum  
2. Cool to Dehumidify  
9
 
Table 5—Dehumidification Selections  
DEHUMIDIFY SET POINT  
DISPLAY  
SELECTION  
MODE DISPLAY  
FAN DISPLAY  
Normal Dehumidify  
Cool to Dehumidify  
Dehumidify OFF  
Blank  
COOL  
Blank  
Blank  
Blank  
Blank  
Dehumidify Set Point Value  
Dehumidify Set Point Value  
OF  
humidity removal is desired, this should be done, if possible. Fan  
coils have the capability of removing this off delay, furnaces do  
not. On FK or FV Fan Coils, set delay tap to 0/0. On standard fan  
coils, a jumper can be cut to disable off delay. Refer to fan coil  
Installation Instructions for details. If FAN is set for continuous  
operation (fan ON icon displayed), G output is turned off for 5  
minutes at the end of each cooling cycle as long as dehumidify  
demand exists.  
Carrier 58MVP Furnaces also have a DEHUM input. The DE-  
HUM input acts differently depending on which style of variable-  
speed furnace control you have. The older style variable-speed  
furnace control DOES NOT have a DE connection while the newer  
style variable-speed furnace control has a DE connection. Both of  
these variable-speed furnace controls function the same except the  
DEHUM logic is reversed.  
On the older style variable-speed furnace controls, a field-  
supplied relay is required between the Thermidistat Control  
and furnace. The relay coil is connected between DHUM output  
on the Thermidistat Control and COM terminal on the furnace  
control. Its normally closed contact is connected between R and  
DEHUM terminals on the furnace control, where the DEHUM  
terminal is a spade lug located next to the transformer secondary  
connections. (See Wiring Diagram Reference Chart and Fig. 21  
through 24 in Wiring Diagram literature). When a dehumidify  
demand exists, relay is de-energized, and normally closed contacts  
supply 24vac to the furnace DEHUM terminal. As a result the  
furnace control reduces the blower airflow by 15 percent.  
Like humidify, dehumidify actions are initiated when humidity is  
2 percent above set point and are terminated when humidity drops  
to 2 percent below set point. This prevents unnecessary toggling of  
dehumidify actions when humidity is near set point.  
The vacation mode contains additional dehumidify features de-  
signed to protect an unoccupied home. Refer to the "Vacation"  
section for additional information.  
With any dehumidify selection, if the system has a 2-speed  
compressor (DIP switch No. 2 is ON) and does NOT have a  
variable-speed blower (Configuration Option No. 5 set to OFF), all  
cooling will be done at high speed while dehumidify demand  
exists. This is because the combination of 2-speed compressor  
without variable-speed blower generally has poor water removal  
on low speed.  
On newer style variable-speed furnace controls, a field-  
supplied relay IS NOT required. The DHUM output on the  
Thermidistat Control is instead connected directly to the DEHUM  
terminal on the furnace control, where the DEHUM terminal is a  
spade lug located next to the transformer secondary connections.  
In addition the DE jumper located next to the DEHUM terminal  
must be removed to enable the DEHUM input. (See Wiring  
Diagram Reference Chart and Fig. 25 through 28 in Wiring  
Diagram literature). When a dehumidify demand exists the furnace  
control reduces the blower airflow by 21 percent.  
Dehumidify Output and Equipment Connections  
When there is a dehumidify demand, dehumidify output is  
activated, which means that a 24-vac signal is removed from the  
DHUM output terminal. In other words, dehumidify output logic is  
reversed — output is turned ON when no dehumidify demand  
exists and is turned OFF when demand exists. This logic reversal  
has come about from historical use of a standard humidistat to do  
dehumidification. The humidistat contacts open on high humidity,  
thus removing a 24-vac signal to initiate dehumidification. Equip-  
ment has been designed to operate in this manner, so the  
Thermidistat Control must now accommodate the existing equip-  
ment.  
VACATION  
A vacation selection is available specifically for times where the  
home will not be occupied for an extended period. For conve-  
nience, 1 button selects vacation mode which is indicated by OUT  
icon on display. Vacation mode also has an automatic hold,  
meaning that set points are not affected by the programmed  
schedule. While in vacation mode, the system provides tempera-  
ture and humidity protection for the home in all seasons, but not  
comfort.  
Carrier FK and FV Series Variable-Speed Fan Coils, all 58UHV  
and 58UXV 80% Variable-Speed Furnaces, and 58MVP 90%  
Variable-Speed Furnaces with the DE connection have dehumidify  
inputs which connect directly to Thermidistat Control DHUM  
output. They are compatible with the reverse logic output and will  
reduce their cooling CFM by approximately 20 percent when a  
dehumidify demand is present.  
Vacation Set Points  
A special set of temperature and humidity set points exists which  
are active in vacation mode. They are adjustable by the home-  
owner, are exclusively for vacation mode, and are remembered  
from 1 vacation selection to the next. These set points will be  
higher for cool and dehumidify and lower for heat and humidify  
than those of occupied mode.  
The FK and FV Series Fan Coils have a terminal marked DH  
which should be connected to the Thermidistat Control DHUM  
output. Jumper J1 on fan coil MUST be removed. It is located  
behind the DH terminal. Additionally blower delay tap on fan coil  
should be set to 0/0 (no ON delay and no OFF delay) when using  
cool to dehumidify. With this selection, the blower stops when G  
signal is removed, preventing re-evaporation of water from the coil  
which would occur during the normal 90 sec blower off delay. (See  
Wiring Diagram Reference Chart and Fig. 5 through 8 in Wiring  
Diagram literature).  
Vacation Humidification  
Normal humidify is available, using vacation set points. Humidi-  
fication by fan only is not available as vacation selection. Auto  
humidification is available, adjusting its set point with outdoor  
temperature the same as when occupied. The maximum humidity  
set point can be adjusted separately from the occupied value, but  
it must always be less than occupied value. This allows humidi-  
fication to track outdoor temperature identically, whether occupied  
or vacation, but allows maximum humidification to be less when  
unoccupied. Vacation humidification can be turned off indepen-  
dently of occupied humidification.  
On 58UHV and 58UXV Furnaces, a green wire marked DHUM is  
connected to a spade lug which is connected to the G input  
terminal. Unplug spade lug, cut off spade receptacle from wire  
end, and splice a wire between green DEHUM wire and Thermi-  
distat Control DHUM terminal. (See Wiring Diagram Reference  
Chart and Fig. 17 through 20 in Wiring Diagram literature).  
10  
 
Thermidistat Control Troubleshooting  
SYMPTOM  
No display  
WHAT TO CHECK  
Open Thermidistat Control. Check for 24vac between R and C at screw terminals on mounting base. Reassemble, making  
sure pins on board engage sockets in mounting base. If display does not appear, replace Thermidistat Control.  
"--" in place of room temperature  
Thermidistat Control cannot properly read room temperature. Replace Thermidistat Control.  
"E3" or "--" in place of outdoor temperature Thermidistat Control cannot properly read outdoor temperature. Check outdoor sensor and its wiring.  
"E4" or "E5"  
"E6"  
Internal failure. Replace Thermidistat Control.  
System is stuck in defrost. Check wiring and heat pump defrost control board.  
"Clean Filter" icon displayed  
Cooling or heating will not come on  
Humidify or dehumidify will not come on  
Filter timer has expired. Clean or replace filter and then press VACATION and HOLD/END buttons together to reset.  
See Installer Setup to force heating or cooling. Check for 24vac at equipment terminals. If not present, check wiring.  
See Installer Setup to force HUM or DEHUM. Check for 24vac at equipment terminals. If not present, check wiring.  
Vacation Dehumidification  
located under heat set point. These 2 arrows are also used to  
indicate state of humidify and dehumidify outputs. See next  
section.  
Normal Dehumidify, Cool to Dehumidify, and Dehumidify OFF,  
are all available in vacation mode, and selection of 1 of these can  
be different from that of occupied. Vacation dehumidification  
selection and set points are remembered the next time vacation is  
used.  
HUMIDIFY AND DEHUMIDIFY INDICATORS  
The humidity screen (selected by pressing the HUMIDITY button)  
uses the same triangles referenced in the above paragraph to  
indicate the state of the HUM and DHUM outputs. When  
humidification or dehumidification is active, the triangle under its  
set point is turned on.  
Cool to dehumidify operates slightly differently, allowing the  
home to be cooled to as low as 70°F when trying to achieve  
dehumidify set point. The balance between dehumidify and  
temperature set point adjustments is 1 percent set point increase  
per degree of overcooling for temperatures below 76°F. For  
example, at 74°F dehumidify set point is raised 2 percent, and at  
72°F dehumidify set point is raised 4 percent. At temperatures  
above 76°F, dehumidify set point is not changed.  
AUTO CHANGEOVER  
When auto changeover mode is selected, a change from heat to  
cool (or vice versa) will not occur until an opposite mode demand  
has existed for 20 minutes. If set point is changed, 20-minute  
requirement is deleted.  
OPERATIONAL INFORMATION  
FIVE-MINUTE COMPRESSOR TIMEGUARD  
EMERGENCY HEAT MODE  
When Thermidistat Control is configured as a heat pump and  
emergency heat is selected, all Y signals are locked out, and W  
becomes energized upon a call for heat.  
This timer prevents compressor from starting unless it has been off  
for at least 5 minutes. It can be defeated for 1 cycle by  
simultaneously pressing FAN button and INCREASE TEMPERA-  
TURE button.  
POWER ON CHECK  
When AC power is first applied, all segments of display are turned  
on for a few seconds. Following this, temperature display indicates  
model/configuration via following 2-digit code:  
FIFTEEN-MINUTE CYCLE TIMER  
This timer prevents the start of a heating or cooling cycle until at  
least 15 minutes after the last start of the same cycle. Its function  
is to assure that equipment is not cycled more than 4 times per hr.  
This timer is defeated for 1 cycle when desired temperature is  
manually changed. It can also be defeated for 1 cycle by  
simultaneously pressing FAN button and INCREASE TEMPERA-  
TURE button.  
AC—1-speed air conditioner, HP—1-speed heat pump, A2—2-  
speed air conditioner, H2—2-speed heat pump, HS—1-speed heat  
pump with 3-stage auxiliary heat, dF—dual fuel, d2—dual fuel  
with 2-speed.  
ERROR CODES  
FIFTEEN-MINUTE STAGING TIMER  
"--" — If Thermidistat Control cannot properly read room tem-  
perature, display will indicate -- and all outputs (except  
fan if on) will turn off.  
E1, E2 — There is no E1 or E2 error message.  
E3 — If Thermidistat Control cannot properly read outdoor  
temperature, and it is needed for proper operation, display  
will indicate E3.  
In multistage heating or cooling, this timer prevents any higher  
stage from turning on until preceding stage has been on for 15  
minutes. This timer is defeated if temperature error is greater than  
5°F (usually due to a large change in desired temperature).  
THREE-MINUTE MINIMUM ON TIME  
In normal operation, when a stage turns on, it will not turn off for  
a minimum of 3 minutes. If the set point is changed, this timer is  
automatically canceled, allowing the equipment to turn off imme-  
diately when the demand is removed.  
E4 — If Thermidistat Control’s internal memory fails, E4 will be  
displayed. Replace Thermidistat Control.  
E5 — If Thermidistat Control cannot properly read humidity, E5  
will be displayed. Replace Thermidistat Control.  
E6 — If defrost cycle continues for longer than 15 minutes. E6  
will be displayed. Check heat pump wiring or for failed  
heat pump defrost control.  
HEAT/COOL SET POINTS (DESIRED TEMPERATURE)  
A minimum difference of 2° is enforced between heating and  
cooling desired temperatures. This is done by allowing 1 setting to  
"push" the other, to maintain this difference. This difference is  
adjustable via Configuration Option 14.  
SMART RECOVERY  
With Smart Recovery selected, transition out of setback begins a  
fixed time period before selected recovery time and gradually  
adjusts room temperature so desired temperature will be achieved  
at selected recovery time. The fixed time period is 1.5 hr. It  
operates in both heating and cooling. This only applies to  
programmable operation.  
EQUIPMENT ON INDICATORS  
When cooling equipment is on, a COOL icon preceded by a small  
triangle is displayed below cool set point. While cooling equip-  
ment turn on is delayed by a staging or cycle timer, triangle will  
flash. The same is true for HEAT icon and its preceding triangle  
11  
 
THERMIDISTAT CONTROL CONFIGURATION RECORD  
Date  
Owner/Operator  
Thermidistat Model No.  
B) Mode Settings  
A) Hardware Configuration  
Switch A ____ AC/HP Select. (OFF = AC)  
Switch B ____ 1 or 2-Speed Compressor. (OFF = 1-Speed)  
Switch C ____ Smart Recovery. (OFF = Enable)  
Switch D ____ Installer Test. (OFF = Disable)  
____ Hold (On or Off)  
____ Mode (Off, Heat, Cool, Auto, Eheat)  
____ Heating Set Point Value  
____ Cooling Set Point Value  
____ Fan (Auto or On)  
C) Configuration Options  
1
2
3
4
5
6
7
8
9
______ Anticipator (1-9: factory default = 3)  
______ Clean Filter Timer (Off or 1-9: factory default = 2)  
______ Fahrenheit or Celsius (F or C: factory default = F)  
______ Fan On with W (Off or On: factory default = Off)  
______ Variable Speed ICM Motor (Off or On: factory default = Off)  
______ Cooling Lockout Below 55°F (Off or On: factory default = Off)  
______ Variable Speed Superdehumidify (Off or On: factory default = Off, or Not Available)  
______ Auxiliary Heat Lockout Setting (Off or 5-55°F: factory default = Off, or Not Available)  
______ Intelligent Heat Staging Selection (Off or On: factory default = Off, or Not Available)  
10 ______ Dual Fuel Equipment Selection (Off or On: factory default = Off, or Not Available)  
11 ______ Balance Point Setting (Off or 5-55°F: factory default = Off, or Not Available)  
12 ______ Defrost Heat Select (0, 1, 2, 3: factory default = 0, or Not Available)  
13 ______ Room Temperature Offset (-5 to +5: factory default = 0)  
14 ______ Heat/Cool Dead Band (0 to 6: factory default = 2)  
15 ______ Enable Auto Mode (On or Off: factory default = On)  
16 ______ Enable Super Comfort Heat Mode (Off or On: factory default is Off, or not Available)  
17 ______ Enable Non-Programmable Operation (nP or P: factory default is P for programmable)  
D) Schedule  
WAKE  
DAY  
EVE  
SLEEP  
TIME HEAT COOL TIME HEAT COOL TIME HEAT COOL TIME HEAT COOL  
Mon  
Tue  
Wed  
Thu  
Fri  
Sat  
Sun  
E) Humidity Settings  
Heat Mode  
Cool Mode  
Selection  
Set Point% Display  
_________ (d hu)  
_________ (d hu, COOL)  
no set point (d hu, OF)  
Selection  
Set Point% Display  
_________ (hu)  
_________ (hu, Fan)  
_________ (hu, AUTO)  
Normal Dehumidify  
Cool to Dehumidify  
Dehumidify Off  
Normal Humidify  
Fan Humidify  
Auto Humidify  
Auto and Fan Humidify _________ (hu, AUTO, Fan)  
Humidify Off no set point (hu, OF)  
E) Vacation Humidity Settings  
Heat Mode  
Cool Mode  
Selection  
Set Point% Display  
Selection  
Set Point%  
Display  
Normal Dehumidify  
Cool to Dehumidify  
Dehumidify Off  
_________ (d hu, OUT)  
_________ (d hu,OUT,COOL)  
no set point (d hu, OUT,OF)  
Normal Humidify  
Auto Humidify  
Auto and Fan Humidify _________ (hu, OUT,AUTO, Fan)  
Humidify Off no set point (hu, OUT, OF)  
_________ (hu, OUT)  
_________ (hu, OUT,AUTO)  
A99015  
Copyright 1999 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231  
tstt23si  
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.  
Book  
Tab misc. misc.  
1
4
PC 101  
Catalog No. 03TS-TA17  
Printed in U.S.A.  
Form TSTAT-23SI  
Pg 12  
8-99  
Replaces: TSTAT-19SI  
 

Belkin Modem F5D5730au User Manual
Bissell Pet Care Product 33N7 User Manual
Blanco Indoor Furnishings 157 133 User Manual
Blomberg Range 24100 SS User Manual
Bolens Lawn Mower 111 060A User Manual
Braun Styling Iron MS 1 User Manual
Cannon Electric Pressure Cooker 10520G User Manual
Carson Car Amplifier SA 500 11 14V User Manual
Chicago Electric Battery Charger 96728 User Manual
Chicago Electric Saw 94245 User Manual