Honeywell T874 Product Data page 216

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
H1 ANTICIPATOR
H1 FALL
H2
ANTICIPATOR
H2
FALL
RISE
C1
ANTICIPATOR
CHANGEOVER
RISE
C1
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
Fig. 235. Schematic and hookup of T874G and Q674F. Used in heat pump applications.
THERMOSTAT
H1 ANTICIPATOR
FALL
H1
FALL
H2 ANTICIPATOR
H2
C1
RISE
RISE
C2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
Fig. 236. Schematic and hookup of T874A-D with Q674C. Used in standard applications.
60-2485—8
SUBBASE
2
FAN
SWITCH
3
AUTO
ON
4
5
SYSTEM
SWITCH
OFF
8
COOL
9
AUTO
HEAT
EM. HT.
10
FAN
1
SWITCH
AUTO
ON
4
6
8
SYSTEM
SWITCH
9
OFF
AUTO
10
11
AUX. HT.
LED (GRN)
EM. HT.
LED (RED)
SUBBASE
SERVICE
LED (RED)
216
SYSTEM COMPONENTS
R
RTD1 OTD1
EHR1
W2
ODT2
EHR2
RTD1
X
SYSTEM
MONITOR
L
G
RD
COOL
CHANGEOVER VALVE
O
E
COMPRESSOR
CONTACTOR
LACO
Y
SYSTEM COMPONENTS
CONTROL MODULE
W1
HEAT RELAY 2
HEAT RELAY 1
W2
HEAT DAMPER
B
RH
RC
COOL DAMPER
O
G
FAN RELAY
Y2
COMPRESSOR
RELAY 1
COMPRESSOR
RELAY 2
Y1
A
L1
(HOT)
L2 1
RTD2
RTD3
FAN
RELAY
EM. HT.
RELAY
CHP
M7064
1
1
M7570