Honeywell T874 Product Data page 196

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
H1 ANTICIPATOR
H1
FALL
CO
RISE
C1 ANTICIPATOR
1
C1
RISE
2
Fig. 205. Schematic and hookup of T874H with Q674C. Used in heat pump applications.
THERMOSTAT
H1
H1 ANTICIPATOR
FALL
H2
ANTICIPATOR
H2
FALL
CO
RISE
C1 ANTICIPATOR
RISE
CO
C1
Fig. 206. Schematic and hookup of T874J with Q674J. Used in heat pump applications.
60-2485—8
2
3
4
6
8
SYSTEM
SWITCH
9
10
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
LEDS ON SOME MODELS.
2
3
4
5
6
8
SUPL. HT.
9
10
11
12
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
SUBBASE
FAN SWITCH
AUTO
ON
LED
(RED)
OFF
AUTO
LED
(RED)
SUBBASE
FAN SWITCH
AUTO
ON
SYSTEM
SWITCH
ON
OFF
196
SYSTEM COMPONENTS
COOL CHANGEOVER
VALVE
Y1
COMPRESSOR
CONTACTOR
Y2
FAN RELAY
G
R
L
X1
C
2
X2
SYSTEM COMPONENTS
R
COMPRESSOR
CONTACTOR
Y
FAN RELAY
G
H.C.R.1
W2
SUPL. HT.
LED (RED)
O.D.T.
L
H.C.R.1
C
E
H.C.R.2
O
COOL
CHANGEOVER
VALVE
L1
(HOT)
L2
1
M2983
L1
(HOT)
L2
1
H.C.R.2
H.C.R.3
M2984