Honeywell T874 Product Data page 177

THERMOSTAT
2
H1
FALL
H1 ANTICIPATOR
3
4
5
6
H2
ANTICIPATOR
H2
8
FALL
9
CO
C1 ANTICIPATOR
RISE
10
RISE
C1
POWER SUPPLY. PROVIDE DISCONNECT
1
MEANS AND OVERLOAD PROTECTION AS REQUIRED.
ON SOME MODELS, Y TERMINAL MAY BE LABELED Y1.
2
EMERGENCY HEAT RUNS CONTINUOUSLY WHEN SWITCH IN IN EM. HT. POSITION.
3
Fig. 170. Schematic and hookup of T874G with Q674F. Used in heat pump applications.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
SUBBASE
FAN SWITCH
AUTO
ON
SYSTEM
SWITCH
OFF
EM. HT.
3
HEAT
AUTO
COOL
177
SYSTEM COMPONENTS
W3
W1 RELAY
W3 RELAY
W1
B RELAY
B
FAN RELAY
G
R
AUX. HT. RELAY
W2
AUX. HT.
LED (GREEN)
X
EM. HT.
LED (RED)
COMPRESSOR
L
FAULT
E
COOL
CHANGEOVER
EM. HT.
VALVE
RELAY
O
COMPRESSOR
CONTACTOR
2
Y
M5987A
L1
(HOT)
L2
1
60-2485—8