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®
ELECTRONIC THERMOSTATS  
MODEL 8336  
2
Heat / 2 Cool Digital  
Heat Pump  
User’s Manual  
Installation and  
Operation  
IMPORTANT SAFETY INFORMATION  
WARNING:  
•
Always turn off power at the main power source by unscrewing  
fuse or switching circuit breaker to the off position before installing,  
removing, cleaning, or servicing thermostat.  
•
•
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•
Read all of the information in this manual before installing or  
programming this thermostat.  
This is a 24V AC low-voltage thermostat. Do not install on voltages  
higher than 30V AC.  
All wiring must conform to local and national building and electrical  
codes and ordinances.  
Do not short (jumper) across terminals on the gas valve or at the  
system control to test installation. This will damage the thermostat  
and void the warranty.  
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Features  
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Multi Stage heating and cooling control.  
Zone system compatible as a master thermostat.  
Multi-Colored LED indicators for system status.  
Low battery indicator.  
Fahrenheit/Celsius display option.  
Adjustable from 45°F (4°C) to 90°F (32°C).  
Accuracy within ± 1 degree.  
Adjustable temperature differential: 1-3 degrees F.  
Automatic heating shutdown if temperature exceeds 90°F (32°C).  
Replacing Existing Thermostat  
1.  
Turn off power to heating and cooling system.  
2.  
Remove cover of old thermostat to expose wires.  
Do not disconnect wires. (Fig. 1)  
3.  
Label wires per Table 1.  
Table 1  
Old Label  
New Label  
Description  
R, V-VR or VR-R  
Y, Y1 or M  
R
24 VAC, Return  
Y
O
B
Stage 1 Cooling/Heating  
Circuit  
O or R  
B
Reversing Valve,  
(
Cooling Mode)  
Reversing Valve  
Heating Mode)  
(
F or G  
Y2  
G
Fan control relay  
Y2  
2nd Stage Cooling  
Circuit  
W1 or W2 or W-U  
W2  
2nd Stage Heating  
Control  
L or X  
E
L
System Monitor LED  
E
Emergency Heating  
Circuit  
C, X or B  
C
24 VAC, Transformer  
Common Side  
*NOTE: This thermostat requires a 24V common wire for proper operation.  
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4.  
5.  
6.  
After labeling wires, remove wires from terminals.  
Remove existing thermostat base from wall.  
Refer to the following section for instructions on how to  
install thermostat.  
Figure 1  
Installing the Model 8336 Thermostat  
NOTE: For new installations, mount thermostat on inside wall, 4-5 feet  
above the floor. Do not install behind a door, in a corner, near air vents, in  
direct sunlight, or near any heat or steam generating fixtures. Installation  
at these places will affect thermostat operation.  
1. Turn power off to the heating  
and cooling systems.  
2. Place COOL-OFF-HEAT-EM  
In OFF position.  
COOL-OFF-HEAT-EM  
COOL-OFF-HEAT-EM  
FAN: AUTO  
-
ON  
AUX CHECK EMER  
FAN: AUTO - ON  
3. Place FAN: AUTO-ON switch  
Into AUTO position.  
4. Remove the cover using a coin  
or screwdriver.  
Figure 2  
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5. Place thermostat against the wall at desired location. Make sure  
wires will feed through opening on base of thermostat.  
6. Mark placement of mounting holes. See Fig. 3.  
Set base aside.  
Mounting Holes  
Batteries NOT Required.  
figure 3  
7
. Drill the marked holes using a 3/16" drill bit. NOTE: Enclosed  
plastic anchors do not require a drilled hole for drywall.  
8. Tap plastic anchors into the wall.  
9. Align base with plastic anchors and feed wires  
through opening.  
10. Secure base to wall with supplied screws.  
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11. Connect wires to terminal strip. Refer to wiring diagrams on other  
side of this sheet. Make sure wire connections are secure.  
12. Put the °F/°C switch to either °F for Fahrenheit display  
or °C for Celsius display readout.  
°
F/°C Switch  
Batteries NOT Required.  
figure 4  
13. Replace cover onto thermostat by snapping into place.  
14. Turn on power to system. Test thermostat as described  
in the following section.  
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Operation  
Setting or Changing the Setpoint Temperature  
1
. Press either the  
or  
button.  
The display will show the current  
temperature setpoint.  
C
COOL-OFF-HEAT-EM  
FAN: AUTO  
-
ON  
AUX CHECK EMER  
2
. Press either the  
or  
button  
to adjust the temperature setting  
either up or down.  
The display will return to the room temperature display five seconds after  
the last input and the new setpoint will be saved.  
Changing Temperature Differential  
IMPORTANT: The temperature differential is factory set at 1 (1°). This  
means that whenever the room temperature changes by one half of a  
degree from the temperature setting, the system will turn on. If the  
system turns on too often, increase the temperature differential.  
1
. Press both  
at the same time and hold for one  
second.  
and  
buttons  
COOL-OFF-HEAT-EM  
FAN: AUTO  
-
ON  
AUX CHECK EMER  
2
. Press either the  
or  
button  
to adjust the temperature  
differential up or down.  
The display will show:  
Differential  
Setting  
Degrees  
1°F/.5°C  
1
2
3
2°F/1.0°C  
3°F/1.5°C  
The display will return to the room temperature five  
seconds after the last input.  
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To Test Thermostat  
WARNING: DO NOT SHORT (JUMPER) ACROSS TERMINALS OF GAS  
VALVE OR SYSTEM CONTROL TO TEST OPERATION. THIS WILL DAMAGE  
THE THERMOSTAT AND VOID YOUR WARRANTY.  
CAUTION: Do not switch system to cool if the temperature is below 50°F (10°C).  
This can damage the air conditioning system and cause personal injury.  
1. Place the COOL-OFF-HEAT-EM  
switch into the COOL position  
COOL-OFF-HEAT-EM  
2
. Press the  
temperature setting is at least  
degrees below the room  
button until the  
3
temperature. The air conditioning  
system should turn on within  
a few seconds.  
NOTE: When in the COOL mode (or HEAT for single stage heat pumps),  
once the thermostat turns off, a built in 5-minute delay prevents the  
system from turning on again. This protects the compressor. No  
additional time delay relay is required.  
COOL-OFF-HEAT-EM  
3
. Put the COOL-OFF-HEAT-EM switch  
into the OFF position. The air  
conditioning system should turn off.  
COOL-OFF-HEAT-EM  
4. Put the COOL-OFF-HEAT-EM switch  
into the HEAT position.  
5
. Press the  
temperature setting is at least  
degrees above room temperature.  
button until the  
3
The heating system should turn on.  
The fan may not turn on immediately,  
depending upon the fan delay built  
into the furnace.  
COOL-OFF-HEAT-EM  
FAN: AUTO - ON  
6
. Put the COOL-OFF-HEAT-EM switch  
into the OFF position. The heating  
system should turn off. The fan may  
continue to run for a short period  
of time.  
7
. Put the FAN: AUTO-ON switch to the  
ON position. The blower fan should  
turn on.  
8
. Put the FAN: AUTO-ON switch to  
the AUTO position. The blower fan  
should turn off.  
FAN: AUTO - ON  
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Changing Fahrenheit (F) to Celsius (C)  
The thermostat is preset to display the temperature in degrees Fahrenheit.  
You may change the display readout to Celsius if desired.  
1
. Move the manual switch marked “F” (Fahrenheit) and “C” (Celsius)  
located at the top center of the circuit board to the desired setting.  
(see page 5)  
2. Press RESET button located lust below the LCD display to register  
the change.  
The display will change to show the temperature in your desired  
temperature scale. To return the thermostat to its original setting,  
repeat steps 1 and 2 above.  
LED Indicators  
The LED indicators are used to indicate system activity. The AUX indicator  
illuminates during a call for second stage heating. The auxiliary stages  
are used to maintain comfort during extremes in weather conditions. If  
the AUX LED is illuminated too frequently during periods of moderate  
temperature, check the differential settings (page 6).  
The CHECK indicator is used to monitor system status. If the CHECK  
indicator is illuminated, call your local HVAC service provider.  
The EMER indicator is illuminated only when the system switch is moved  
to the EM, emergency heat position. The EM position is used only when  
the primary stage of heat is not functioning or requires service.  
Troubleshooting  
Symptom  
Remedy  
Thermostat does not turn  
on system.  
Check Wiring  
(see INSTALLATION).  
Check fuse. Replace with 2 amp  
fuse if fuse has opened.  
Thermostat turns on and  
off too frequently.  
Increase Temperature Differential  
(see DIFFERENTIAL).  
System fan does not  
operate properly.  
Move fan option switch to either  
gas or electric, to match system  
(see INSTALLATION).  
Thermostat does not display  
proper room temperature.  
Check “F” Fahrenheit /”C” Celsius  
switch located at top center of  
circuit board for proper position.  
If a new selection is made, press  
“
RESET” button located directly  
below LCD display.  
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If problems with thermostat cannot be solved, call:  
Technical Support: 608-257-8801  
Monday-Friday 7:45 am-5:00 pm CST  
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Wiring Diagrams  
The following is just a sample of the most common types of HVAC  
systems. Refer to your systems installation manual for wiring information.  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO CARRIER  
SPLIT SYSTEM CONDENSORS AND HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
R
Y1  
O
B
G
E
W2  
L
C
Y2  
2
4 VAC, RETURN  
R
Y
COMPRESSOR CONTACTOR  
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
O
G
EMERGENCY HEATING CIRCUIT  
E
2
ND. STAGE HEATING CIRCUIT  
SYSTEM MONITOR LED  
4 VAC, COMMON  
W2  
L
2
C
W3  
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
APRILAIRE MODEL 8336 HEAT PUMP CONVERSION TO COLEMAN HEAT PUMPS  
3
000 SERIES HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
Y1  
W2  
Y2  
R
O
B
G
E
L
C
2
4 VAC, RETURN  
R
Y
COMPRESSOR CONTACTOR  
REVERSING VALVE [HEATING MODE]  
FAN CONTACTOR CIRCUIT  
B
G
EMERGENCY HEATING CIRCUIT  
E
2
ND. STAGE HEATING CIRCUIT  
SYSTEM MONITOR LED  
4 VAC, COMMON  
W2  
L
2
X
O
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
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APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO COMFORTMAKER  
CYC SERIES HEAT PUMP SYSTEMS  
NOTE 1: E AND W2 TERMINALS  
JUMPERED AT THERMOSTAT  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
NOTE 2: W2 TERMINAL ON  
COMFORTMAKER PCB CAPPED  
NOTE 3: X TERMINAL ON  
COMFORTMAKER PCB CAPPED  
R
Y1  
O
B
G
E
W2  
L
C
Y2  
2
4 VAC, RETURN  
R
Y
COMPRESSOR CONTACTOR  
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
O
G
2
ND. STAGE HEATING CIRCUIT  
W1  
W2  
X
OUTDOOR THERMOSTAT [CAPPED]  
DEFROST SENSOR [CAPPED]  
2
4 VAC, COMMON  
C
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO HEIL-QUAKER  
67.814 SERIES AND PH50 SERIES HEAT PUMP SYSTEMS  
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NOTE 1: E AND W2 TERMINALS  
JUMPERED AT THERMOSTAT  
NOTE 2: W2 TERMINAL ON  
HEIL-QUAKER PCB CAPPED  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
Y1  
W2  
Y2  
R
O
B
G
E
L
C
2
4 VAC, RETURN  
R
Y
O
G
COMPRESSOR CONTACTOR  
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
2
3
2
ND. STAGE HEATING CIRCUIT [SEQUENCER 1]  
RD. STAGE HEATING CIRCUIT [SEQUENCER 2]  
4 VAC, COMMON  
W1  
W2  
C
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
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APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO PAYNE  
RELIANT AND ENDURA MODEL HEAT PUMP SYSTEMS  
NOTE 1: W3 TERMINAL ON  
PAYNE PCB CAPPED  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
Y1  
W2  
Y2  
R
O
B
G
E
L
C
2
4 VAC, RETURN  
R
Y
COMPRESSOR CONTACTOR  
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
O
G
EMERGENCY HEATING CIRCUIT  
E
2
ND. STAGE HEATING CIRCUIT  
W2  
L
SYSTEM MONITOR LED  
2
3
4 VAC, COMMON  
RD. STAGE HEATING CIRCUIT [CAPPED]  
C
W3  
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO RHEEM/RUUD  
HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
R
Y1  
O
B
G
E
W2  
L
C
Y2  
2
4 VAC, RETURN  
R
Y
COMPRESSOR CONTACTOR  
REVERSING VALVE [HEATING MODE]  
FAN CONTACTOR CIRCUIT  
B
G
EMERGENCY HEATING CIRCUIT  
E
2
ND. STAGE HEATING CIRCUIT  
SYSTEM MONITOR LED  
4 VAC, COMMON  
W2  
L
2
X
B
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
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APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION  
TO WEATHERTRON HEAT PUMPS  
NOTE 1: E AND W2 TERMINALS  
JUMPERED AT THERMOSTAT  
NOTE 2: X2 TERMINAL CAPPED AT  
WEATHERTRON PCB  
NOTE 3: T TERMINAL CAPPED AT  
WEATHERTRON PCB  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
Y1  
W2  
Y2  
R
O
B
G
E
L
C
2
4 VAC, RETURN  
R
Y
O
G
COMPRESSOR CONTACTOR  
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
X2  
2
2
ND. STAGE HEATING CIRCUIT  
4 VAC, COMMON  
W-U  
B
T
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO YORK  
-
E1CS, -E1FB, -E1FH HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
Y1  
W2  
Y2  
NOTE 1: E AND W2 TERMINALS  
JUMPERED AT THERMOSTAT  
R
O
B
G
E
L
C
2
4 VAC, RETURN  
R
Y
O
G
COMPRESSOR CONTACTOR  
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
2
ND. STAGE HEATING CIRCUIT  
SYSTEM MONITOR LED  
4 VAC, COMMON  
W
X
2
B
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
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APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO LENNOX  
CB19 HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
R
Y1  
O
B
G
E
W2  
L
C
Y2  
2
4 VAC, RETURN  
R
Y
COMPRESSOR CONTACTOR  
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
O
G
EMERGENCY HEATING CIRCUIT  
E
2
ND. STAGE HEATING CIRCUIT  
SYSTEM MONITOR LED  
4 VAC, COMMON  
W1  
L
2
C
T
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO LENNOX  
HP19 AND HP20 HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
R
Y1  
O
B
G
E
W2  
L
C
Y2  
2
4 VAC, RETURN  
V-VR  
COMPRESSOR CONTACTOR  
M
R
F
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
EMERGENCY HEATING CIRCUIT  
E
2
2
ND. STAGE HEATING CIRCUIT  
Y
4 VAC, COMMON  
X
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
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APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO LENNOX  
HP21 WITH CB21 PCB HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
R
Y1  
O
B
G
E
W2  
L
C
Y2  
2
4 VAC, RETURN  
R-VR  
COMPRESSOR CONTACTOR  
Y1  
O
REVERSING VALVE [COOLING MODE]  
FAN CONTACTOR CIRCUIT  
F
EMERGENCY HEATING CIRCUIT  
E
2
2
ND. STAGE HEATING CIRCUIT  
W1  
L
4 VAC, COMMON  
X
Y2  
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT CONVERSION TO LENNOX  
HP22 WITH CB19 PCB HEAT PUMP SYSTEMS  
APRILAIRE MODEL 8336 HEAT PUMP THERMOSTAT  
R
Y1  
O
B
G
E
W2  
L
C
Y2  
2
4 VAC, RETURN  
R-VR  
COMPRESSOR CONTACTOR  
M
R
F
REVERSING VALVE [HEATING MODE]  
FAN CONTACTOR CIRCUIT  
EMERGENCY HEATING CIRCUIT  
E
2
ND. STAGE HEATING CIRCUIT  
Y
SYSTEM MONITOR LED  
L
2
2
4 VAC, COMMON  
X
ND. STAGE COOLING CIRCUIT  
Y2  
THE LOW VOLTAGE TERMINAL DESIGNATIONS AND THEIR DESCRIPTION AND/OR  
FUNCTION ARE USED ON ALL SPLIT SYSTEM CONDENSORS AND HEAT PUMPS  
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Limited Warranty  
®
Your Research Products Corporation Aprilaire Thermostat unit is expressly  
warranted for two (2) years from date of installation to be free from defects in  
materials and workmanship.  
Research Products Corporation’s exclusive obligation under this warranty shall  
be to supply, without charge, a replacement for any thermostat which is found  
to be defective within a two (2) year period and which is returned, together with  
the date of installation, no later than thirty (30) days after said two (2) year  
period by you to either your original supplier or to Research Products  
Corporation, Madison, Wisconsin 53701.  
THIS WARRANTY SHALL NOT OBLIGATE RESEARCH PRODUCTS CORPO-  
RATION FOR ANY LABOR COSTS AND SHALL NOT APPLY TO DEFECTS IN  
WORKMANSHIP OR MATERIALS FURNISHED BY YOUR INSTALLER AS  
CONTRASTED TO DEFECTS IN THE THERMOSTAT ITSELF.  
IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PAR-  
TICULAR PURPOSE SHALL BE LIMITED IN DURATION TO THE AFORESAID  
TWO YEAR PERIOD. RESEARCH PRODUCTS CORPORATION’S LIABILITY  
FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES, OTHER THAN DAMAGES  
FOR PERSONAL INJURIES, RESULTING FROM ANY BREACH OF THE AFORE-  
SAID IMPLIED WARRANTIES OR THE ABOVE LIMITED WARRANTY IS  
EXPRESSLY EXCLUDED. THIS LIMITED WARRANTY IS VOID IF DEFECT(S)  
RESULT FROM FAILURE TO HAVE THIS THERMOSTAT INSTALLED BY A  
QUALIFIED HEATING AND AIR CONDITIONING CONTRACTOR. IF THE  
LIMITED WARRANTY IS VOID DUE TO FAILURE TO USE A QUALIFIED  
CONTRACTOR, ALL DISCLAIMERS OF IMPLIED WARRANTIES SHALL BE  
EFFECTIVE UPON INSTALLATION.  
Some states do not allow limitations on how long an implied warranty lasts or  
the exclusion or limitation of incidental or consequential damages, so the  
above exclusion or limitations may not apply to you.  
This warranty gives you specific legal rights and you may also have other rights  
which vary from state to state.  
P.O. BOX 1467 • MADISON, WI 53701-1467  
™
Products For Better Indoor Air Quality  
B2202516 REV. 12/00  
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