Trane RT-SVX19A-E4 Installation Operation & Maintenance page 45

Thermostat signals are as follows:
R 24VAC power to thermostat
Y1 Call for compressor 1 or first
stage cooling
Y2 Call for compressor 2 or 2nd
stage cooling
G Call for supply fan
W1 Call for heat 1
W2 Call for heat 2
Heat pump only:
X2 Call for emergency heat
O Switchover valve On = cooling,
Off = heating
T Bias for heat anticipation for those
mechanical thermostats that use
this function
RT-SVX19A-E4
Operation
Conventional thermostat –
Gas/ Electric, Electric Heat:
Function when
Input/connection energized :
G (fan) Fan runs continuously
except during
unoccupied mode
(see next page)
Y1 (compressor 1 Compressor #1 runs
or economizer) or economizer
operates
Y2 (compressor 2 Compressor #2 also
or compressor 1 runs, or #1
while economizing) compressor runs
while economizing
W1 (gas / electric 1st stage heat
heat first stage)
W2 (gas / electric 2nd stage heat (if
heat 2nd stage) available)
Conventional thermostat –
Heat Pump
Function when
Input/connection energized
Cooling mode:
G (fan) Fan runs continuously
except during
unoccupied mode
(see next page)
O (reversing valve Reversing valve in
during cooling) cool mode
Y1 + O Compressor #1 runs
(first stage cooling) or economizer
operates
Y1 + Y2 + O Compressor #2 also
(2nd stage cool) runs, or #1
compressor runs
while economizing.
Heating mode:
G (fan) Fan runs continuously
except during
unoccupied mode
(see below)
Y1 (both Both compressors
compressors 1st run
stage heat)
Y2 (during heating No change
– nothing happens)
W2 (electric heat 2nd stage (electric)
2nd stage) heat
X2 (electric heat Electric heat only –
only) no compressors
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.
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