Honeywell T874 - Page 142

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-2485—8 142
Fig. 122. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
H1
C1
2
3
H2
FALL
5
6
H1/C1
ANTICIPATOR
H2
ANTICIPATOR
AUTO
ON
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
FAN RELAY
G
R
K
L
1
C
Y
W1
SERVICE
LED (RED)
EM. HT. LED
(YELLOW)
SERVICE
COMPRESSOR
CONTACTOR
EM. HT. RELAY
AUX. HT. RELAY
POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
1
CO
L1
(HOT)
L2
CHANGEOVER
VALVE
FALL
4
W2
M8379
THERMOSTAT
SUBBASE SYSTEM COMPONENTS
FAN
SWITCH
Z