Replacing Existing Thermostat - Aprilaire 8336 User Manual

Features
• 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
R, V-VR or VR-R
Y, Y1 or M
O or R
B
F or G
Y2
W1 or W2 or W-U
L or X
E
C, X or B
*NOTE: This thermostat requires a 24V common wire for proper operation.
New Label
R
Y
O
B
G
Y2
W2
L
E
C
2
Description
24 VAC, Return
Stage 1 Cooling/Heating
Circuit
Reversing Valve,
(Cooling Mode)
Reversing Valve
(Heating Mode)
Fan control relay
2nd Stage Cooling
Circuit
2nd Stage Heating
Control
System Monitor LED
Emergency Heating
Circuit
24 VAC, Transformer
Common Side