Step 6
Connect Wires
1) Match your previous wire configuration to
the new base. One by one, connect each
wire by inserting the metal end into the
corresponding slot and tightening the screw.
For a 5-wire system, use the guide below to help determine
how wires may convert from your current system to your new
THERM-500.
5
WIRE
* O/B is used in heat pump systems.
TIP:
Use pliers to straighten wire before inserting into new base. Be sure
to cut any excess wire where the insulation extends to the terminal block.
when the wire is installed properly to the terminal block, there should be
no copper exposed.
Old Thermostat
Connector
Function
New Thermostat
Connector
G or F
Fan
G
Y1 or Y
Cooling / Compressor
Y1
W1 or W
Heating
W1/O/B
Rh, R, M, Vr, A
Power
R
C
Common
C
O/B
Rev. Valve
W1/O/B*
W2
2nd Stage Heat
W2
Y2
2nd Stage Cooling
Y2
W3
3rd Stage Heat
W3
OUT -
Outdoor Sensor
Sensor
OUT +
Outdoor Sensor
Sensor
8
