69-0268—11
5
T874G,R MULTISTAGE HEAT PUMP THERMOSTATS AND Q674F,J,L SUBBASES
H2
FALL
H1
FALL
C1
L1
(HOT)
L21
2
2
1POWER SUPPLY. PROVIDE DISCONNECT
MEANS AND OVERLOAD PROTECTION
AS REQUIRED.
FACTORY-INSTALLED JUMPER.
THERMOSTAT SUBBASE SYSTEM COMPONENTS
H1/C1
ANTICIPATOR
H2 ANTICIPATOR
SYSTEM
SWITCH
FAN
SWITCH
AUTO
ON
OFF
HEAT
EM. HT.
COOL
FAN RELAY
EM. HT. RELAY
COOL
CHANGEOVER VALVE
COMPRESSOR
CONTACTOR
M1628A
COMPRESSOR
FAILURE
C815A OUTDOOR
THERMISTOR
SYSTEM
LED (GREEN)
CHECK
LED
(RED)
AUX. HT.
LED
(YELLOW)
2
3
4
5
6
11
12
RESET
Y
T
C
X
E
W1
R
G
O
Fig. 5. Internal schematic and typical hookup for T874R/Q674L in heat pump system with outdoor reset. IncludesAUX. HT., CHECK and SYSTEM LEDs.