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® U.S. Registered Trademark
Copyright © 2001 Honeywell
All Rights Reserved

  

Verify that you have the
right thermostat

Using the compatibility chart 
below, verify that you purchased 
the right CT87 thermostat for 

your heating/cooling system. If 
you are unsure which model is 
right for your system, visit 

www.honeywell.com/
yourhome 

or call Honeywell 

Customer Relations at 

1-800-468-1502.

* CT87A is compatible with 2-wire cooling-only systems.

Heating/Cooling system

Compatible with:

CT87A CT87B

CT87J

Heating only: 

Gas or oil fueled warm air, steam, or hot 

water heat

YES

YES

No

Cooling only: 

Electric air conditioning

YES*

YES

YES

Heating and cooling: 

Gas or oil fueled warm air, 

steam, or hot water heat with electric air conditioning

No

YES

No

Single stage heat pump: 

Outdoor heating/cooling unit 

(compressor) with no auxiliary or backup heat.

No

No

YES

Electric heat furnace with or without cooling:

No

No

YES

Electric baseboard: 

Electric heating strips located just 

above the floor, usually 120–240 volts

No

No

No

Multistage: 

A conventional system with more than one 

stage, or an outdoor heating/cooling unit (compressor) 
with auxiliary or backup heat.

No

No

No

1

CT87A,B,J Round

®

 Thermostat

LOW VOLTAGE (15 TO 30 VAC),

THERMOSTAT AND MOUNTING HARDWARE

Installation Instructions

Summary of Contents for CT87J round

Page 1: ... air steam or hot water heat YES YES No Cooling only Electric air conditioning YES YES YES Heating and cooling Gas or oil fueled warm air steam or hot water heat with electric air conditioning No YES No Single stage heat pump Outdoor heating cooling unit compressor with no auxiliary or backup heat No No YES Electric heat furnace with or without cooling No No YES Electric baseboard Electric heating...

Page 2: ...cuit breaker panel 2 Remove the cover of your old thermostat You may need to unscrew the cover if it is locked on 3 Locate the heat anticipator adjustment scale and lever on the old thermostat Fig 1 In the box below record the number that the adjustment lever points to This is the current amp rating of your heating system Current setting If you cannot find the heat anticipator setting on the old t...

Page 3: ...ng a control that contains mercury in a sealed tube do not place your old control in the trash Contact your local waste management authority for instructions regarding recycling and the proper disposal of this control or of an old control containing mercury in a sealed tube Install the cover ring and wallplate or subbase If installing on the wall Refer to Fig 4 as you work Fig 4 Installing the wal...

Page 4: ...to the wall Position so that the fan and heating cooling switches are on the top 3 Use a pencil to mark the center of the screw holes on the left and right sides of the wallplate or subbase 4 Remove the wallplate subbase and cover ring and drill two 1 16 inch holes at the locations you marked 5 Reposition the cover ring if used and wallplate subbase over the holes pull the wires through the wiring...

Page 5: ...e subbase to the cover ring with two 1 4 inch screws through the screw holes on the left and right sides of the wallplate subbase Level the wallplate or subbase IMPORTANT The wallplate subbase must be level to maintain accu rate thermostat temperature 1 Rotate the wallplate subbase until level as shown in Fig 6 below To level the subbase use the leveling posts directly beneath the HEAT and FAN ind...

Page 6: ... Strip the wire insulation as needed to fit the wires underneath the ter minal screws Fig 7 3 Loosen the terminal screws and slip each wire beneath its matching terminal 4 Securely tighten the terminal screws 5 Push any excess wire back into the wall Wire label Connect to CT87A Connect to CT87B Connect to CT87J R RH 4 V R RH R Rc R Rc W W1 H W W W Y Y1 M Y Y Y G F G G B See Fig 9 B O O See Fig 13 ...

Page 7: ...system Fig 10 CT87B for a 4 wire heating cooling system M20183 CT87A WALLPLATE TO SYSTEM R W Y POWER HEAT M20184 WIRE LABELS LETTERS ON ORIGINAL THERMOSTAT TERMINALS CT87A WALLPLATE 3 WIRE HOT WATER ZONE VALVE R W Y R B W C O O L O F F HEAT FAN ON A U T O M20185 POWER CT87B SUBBASE TO SYSTEM RH G RC W Y FAN HEAT COOL JUMPER RH TO RC ...

Page 8: ... POWER COOL C O O L O F F HEAT FAN ON A U T O M20186 HEAT CT87J SUBBASE TO SYSTEM W G Y P B R O FAN POWER DO NOT ATTACH WIRES TO BOTH B AND O JUMPER W TO Y COOL REVERSING VALVE HEAT REVERSING VALVE C O O L O F F HEAT FAN ON A U T O M20228 CT87J SUBBASE TO SYSTEM W G Y P B O R POWER FAN DO NOT ATTACH WIRES TO BOTH B AND O HEAT PUMP COMPRESSOR COOL REVERSING VALVE HEAT REVERSING VALVE 1 1 IF WIRES A...

Page 9: ...his prevents the thermostat from being damaged 3 Place the thermostat over the wallplate or subbase so that the three captive mounting screws align with the three raised screw holes on the wallplate subbase 4 Tighten the three captive mounting screws as shown in Fig 15 NOTE These screws complete the electrical connections to the thermostat 7 15 12 10 2 6 1 2 5 4 3 HOLE SUITABLE FOR PENCIL POINT TO...

Page 10: ...s off before the set temperature is reached move the anticipator pointer up by 1 amp Never adjust the anticipator below 3 amps Check heating cooling operation Check heating 1 Turn the transparent dial to the left as far as it will go 2 If your CT87 has a subbase set the system switch at HEAT 3 Turn the dial until the temperature on the setting scale Fig 16 exceeds the room temperature that is show...

Page 11: ...the temperature setting below room temperature The cooling system should start 3 Raise the temperature setting above room temperature The cooling system should stop To set the temperature turn the dial until the pointer on the top setting scale lines up with the desired temperature CT87B J switches Switch Setting Result System COOL The thermostat controls your cooling system OFF Both the heating a...

Page 12: ...stallation costs This warranty shall not apply if it is shown by Honeywell that the defect or malfunction was caused by damage which occurred while the product was in the possession of a consumer Honeywell s sole responsibility shall be to repair or replace the product within the terms stated above HONEYWELL SHALL NOT BE LIABLE FOR ANY LOSS OR DAMAGE OF ANY KIND INCLUDING ANY INCIDENTAL OR CONSEQU...

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