Trane ReliaTel - Page 75

RT-SVD03G-EN 75
Operation with a Conventional Thermostat (Constant Volume)
T: (provides heat anticipation signal for those mechanical thermostats that use this feature. If the
thermostat used does not have a “T” terminal, disregard this terminal.
Unoccupied mode: If the thermostat being used is programmable, it will have its own strategy
for unoccupied mode and will control the unit directly. If a mechanical thermostat is being used,
Table 22. Thermostat signals
R 24VAC power to thermostat
Y1 Call for compressor 1 or first stage cooling
Y2 Call for compressor 2 or 2
nd
stage cooling
G Call for supply fan
W1 Call for heat 1 (for modulating gas, see Figure 50, p. 77)
W2 Call for heat 2
Heat pump only:
X2 Call for emergency heat
OSwitchover valve On = cooling, Off = heating
T
Bias for heat anticipation for those mechanical thermostats
that use this function
Table 23. Conventional thermostat – Gas/ Electric, Electric Heat:
Input/connection Function when energized:
G (fan)
Fan runs continuously except during
unoccupied mode (see next page)
Y1 (compressor 1 or economizer)
Compressor #1 runs or economizer
operates
Y2 (compressor 2 or compressor 1 while
economizing)
Compressor #2 also runs, or
#1compressor runs while economizing
W1 (gas / electric heat first stage) 1
st
stage heat
W2 (gas / electric heat 2nd stage) 2
nd
stage heat (if available)
Table 24. Conventional thermostat – Heat Pump
Input/connection Function when energized
Cooling mode:
G (fan)
Fan runs continuously except during
unoccupied mode (see next page)
O (reversing valve during cooling) Reversing valve in cool mode
Y1 + O (first stage cooling)
Compressor #1 runs or economizer
operates
Y1 + Y2 + O (2
nd
stage cool)
Compressor #2 also runs, or #1
compressor runs while economizing.
Heating mode:
G (fan)
Fan runs continuously except during
unoccupied mode (see below)
Y1 (both compressors 1st stage heat)
1.
Both compressors run
Y2 (during heating – nothing happens)
1.
No change
W2 (electric heat 2nd stage) 2nd stage (electric) heat
X2 (electric heat only) Electric heat only – no compressors
1. For units configured with 2-Step Mechanical Heating (Odyssey Independent Circuit
Heat Pump), Y1 will correspond to a request for Compressor 1 operation and Y2 will
correspond to a request for Compressor 2 operation.