9 69-1676—1
Table 2. Terminal Designations on Old and New Thermostats.
NOTES:
1. If wires were connected to both Rh and R terminals on the old thermostat, remove jumper between R and Rc on
the new thermostat and connect Rh to R and R to Rc.
2. If wires will be connected to both R and Rc on the new thermostat, remove jumper between R and Rc.
3. Do not connect both O and B when wiring to a single stage heat pump. Connect O to O. Tape off B with electri-
cal tape and do not use.
4. Tape off wire with electrical tape and do not use.
Terminal on
Old
Thermostat
Connect to Terminals
on CT8775A
Connect To Terminals
on CT8775C Description
R
Rh (see Note 1)
4
V
RR
(see Note 2) Power
Rc
R (see Note 1)
—Rc
(see Note 2) Power for cooling
W, W1, H W W Heat
Y, Y1, M — Y Cooling
G, F — G F an
O — O Changeover in cool. (Single stage heat pump
only).
B (see Note 3) —B (see Note 3) Changeover in heat. (Single stage heat pump
only).
C (see Note 4)
X (see Note 4)
B (see Note 3)
Do not connect. Do not connect. Transformer common
W2, H2Do not continue
installation. Call 1-800-
468-1502.
Do not continue
installation. Call 1-800-
468-1502.
Second stage heat.
Y2Second stage cool.