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Features
• Multi stage heating and cooling control
• Zone system compatible as a master thermostat
• Auxiliary heat
• Fahrenheit/Celsius display option
• Adjustable from 45°F (7°C) to 90°F (32°C)
• Accuracy within ± 1 degree
• Adjustable 1st stage temperature differential: 1°-3°,
2nd stage temperature differential: 2°-6° F
• Automatic heating shutdown if temperature exceeds 90°F (32°C)
• Battery free memory storage
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 (Figure 1).
3. Label wires per Table 1.
Table 1
Old Label New Label Description
R, V-VR or VR-R R 24 VAC, Return
Y, Y1 or M Y1 1st Stage Cooling
Circuit
O or R O Reversing Valve,
(Cooling Mode)
B B Reversing Valve
(Heating Mode)
F or G G Fan Control Relay
Y2 Y2 2nd Stage Cooling
Circuit
W2 or W-U W2 2nd Stage Heating
Control
C, X or B C 24 VAC, Transformer
Common Side
W1 or W W1 1st Stage Heating
Circuit
*NOTE: THIS THERMOSTAT REQUIRES A 24V COMMON WIRE FOR PROPER OPERATION.
2