Honeywell T874 Product Data page 154

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
H1
FALL
H1 ANTICIPATOR
H2 ANTICIPATOR
FALL
H2
RISE
C1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
2
FIELD REMOVABLE JUMPER
Fig. 138. Schematic and hookup of T874L with Q674B. Used in heat pump applications.
THERMOSTAT
H1 ANTICIPATOR
FALL
H1
H2 ANTICIPATOR
H2
FALL
RISE
C1 C1 ANTICIPATOR
C2 ANTICIPATOR
1
C2
RISE
Fig. 139. Schematic and hookup of T874D with Q674F. Used in heat pump applications.
60-2485—8
1
2
FAN SWITCH
AUTO
3
4
5
SYSTEM SWITCH
7
HEAT
8
OFF
COOL
9
C1 ANTICIPATOR
10
1
FAN
2
SWITCH
4
SYSTEM
SWITCH
6
HEAT PUMP
2 STG. HEAT
8
10
11
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
SUBBASE
ON
SUBBASE
AUTO
ON
AUX. HT.
OFF
COOL
154
SYSTEM COMPONENTS
J
R1 NO2
S
SOLIENOID
RELAY
G
R
2
C
AUX. HT. RELAY
H2
COMPRESSOR
R1 NC1
CONTACTOR
H1
R2 NO1
REVERSING
VALVE
O
SYSTEM COMPONENTS
FAN RELAY
G
R
B
W1
COMPRESSOR
RELAY
HEAT PUMP
LED (GREEN)
AUX. HT. RELAY
W2
AUX. HT
LED (RED)
C
COOL CHANGEOVER
VALVE
O
Y1
Y2
COMPRESSOR
CONTACTOR 2
S1 RELAY
S1 NC
FAN RELAY
L1
(HOT)
L2
1
R1 RELAY
M103A
L1
(HOT)
L2
1
COMPRESSOR
CONTACTOR 1
M4730