Honeywell T874 Product Data page 160

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
THERMOSTAT
FALL
H1
H1 ANTICIPATOR
FALL
H2
H2
ANTICIPATOR
RISE
C1
C1
RISE
ANTICIPATOR
3
C2
ANTICIPATOR
C2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2
OPTIONAL FIELD WIRE JUMPER TO ALLOW
SINGLE SYSTEM TRANSFORMER.
FOR Q674F1048, DELETE C2 STAGE.
3
Fig. 149. Schematic and hookup of T874C with Q674F. Used in heat pump applications.
60-2485—8
SUBBASE
1
4
6
8
FAN
SWITCH
AUTO
ON
9
10
SYSTEM
SWITCH
11
OFF
EM. HT.
HEAT
AUTO
COOL
160
W1
Y1
G
W2
EMR2
RC
2
EM. HT. LED
X1
Z
EMR1
RH
EM. HT. RELAY
E
SYSTEM COMPONENTS
EMR4 2R
1R
4R2
2R2
5R
EMR4
3R
THERMAL SWITCHES
FOR HEATING
ELEMENTS
HTR 1
HTR 3
EMR3
HTR 2
OUTDOOR
THERMOSTAT
3R1
EMR1
L1
(HOT) L2
1
1
L2
L1
(HOT)
M8380