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IMPORTANT SAFETY INFORMATION
WARNING:
• Always turn off power at main fuse or circuit breaker panel before
installing, removing, cleaning, or servicing thermostat.
• Read all the information in this manual before installing this
thermostat.
• This is a 24 VAC low-voltage thermostat. Do not install on voltages
higher than 30 VAC.
• 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.
• Do not connect ground to any terminal in this unit.
Step 1: Replacing Existing Thermostat
1. Turn off power to heating system.
2. Remove cover from old thermostat to expose wires (Figure 1).
3. Disconnect wires one at a time from existing terminals. Use enclosed labels
to mark existing wires. Refer to cross references in Table 1 if existing wiring
does not directly match the labels.
4. Remove existing thermostat base from wall.
Old Terminal New Label Description
M,R,Rh,R5 or 5 R Heat transformer, hot side
H,W, or 4 W Heating control
F or G G Fan control relay
NOTE: ON SOME OLDER MODELS, THE C TERMINAL CAN BE EITHER THE COOLING CONTROL
OR THE COMMON SIDE OF THE TRANSFORMER. CHECK FURNACE WIRING DIAGRAM
TO VERIFY C TERMINAL. IF IT IS THE COMMON SIDE OF THE TRANSFORMER, CAP
THE WIRE AND TUCK INTO THE WALL.
Table 1
2
Figure 1
!