Honeywell T874 Product Data page 147

THERMOSTAT
H1/C1
ANTICIPATOR
2
FALL
H1
C1
3
4
FALL
H2 ANTICIPATOR
5
H2
6
POWER SUPPLY. PROVIDE
1
DISCONNECT MEANS AND
OVERLOAD PROTECTION
AS REQUIRED.
Fig. 128. Schematic and hookup of T874R with Q674L. Used in heat pump applications.
THERMOSTAT
H1 ANTICIPATOR
H1
FALL
H2 ANTICIPATOR
FALL
H2
RISE
CO
C1
ANTICIPATOR
RISE
C1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
1
Fig. 129. Schematic and hookup of T874G with Q674L. Used in heat pump applications.
SUBBASE
FAN
SWITCH
AUTO
ON
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
SUBBASE
2
AUTO
FAN
SWITCH
ON
3
4
SYSTEM
6
SWITCH
EM. HT.
HEAT
OFF
COOL
8
9
10
147
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
SYSTEM COMPONENTS
R
RD
A
SERVICE
RTD1
LED (RED)
W3
RTD1
W2
AUX. HT.
LED
(GREEN)
X
EM. HT.
LED
SYSTEM
(YELLOW)
MONITOR
L
G
O
COOL CHANGEOVER
VALVE
E
LACO
Y
B
G
R
W
EM. HT. RELAY
X
B
EM. HT.
LED (RED)
O
Y
COMPRESSOR
CONTACTOR
L1
(HOT)
ODT1
L2
1
EHR1
ODT2
RTD2
EHR2 RTD3
RD
FAN RELAY
EM. HT. RELAY
COMPRESSOR
CONTACTOR
CHP
M5653A
SYSTEM COMPONENTS
FAN RELAY
L1
(HOT)
1
L2
AUX. HT. RELAY
COOL CHANGEOVER VALVE
M102A
60-2485—8