Honeywell CT87A - Manual (Page 7)

CT87A,B,J ROUND® THERMOSTAT
7 69-0274-6
Fig. 8. CT87A for a 2-wire heating only system.
Fig. 9. CT87A for a 3-wire hot water heating only system .
Fig. 10. CT87B for a 4-wire heating/cooling system .
M20183
CT87A WALLPLATE
TO
SYSTEM
R
W
Y
POWER
HEAT
M20184
WIRE LABELS
(LETTERS
ON ORIGINAL
THERMOSTAT
TERMINALS)
CT87A WALLPLATE
3-WIRE
HOT WATER
ZONE VALVE
R
W
Y
R
B
W
C
O
O L
• O
FF
• H
EA
T FAN
ON
•
A U T O
M20185
POWER
CT87B SUBBASE
TO
SYSTEM
R H G
R C
W
Y
FAN
HEAT
COOL
JUMPER R H TO R C