Honeywell T874 - Page 169

T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
169 60-2485—8
Fig. 161. Schematic and hookup of T874G with Q674J. Used in heat pump applications.
H2 ANTICIPATOR
1
SUPL. HT.
LED (RED)
M572
4
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
1
SYSTEM COMPONENTSSUBBASETHERMOSTAT
L1
(HOT
)
L2
1
H1
FALL
H2
FALL
2
4
6
O
G
R
W
2
E
L
C
Y
CO
RISE
C1
RISE
8
9
10
H1 ANTICIPATOR
C1 ANTICIPATOR
SYSTEM
SWITCH
SUPL. HT.
ON
OFF
FAN
SWITCH
AUTO
ON
FAN RELAY
COOL CHANGEOVER VALVE
OUTDOOR
THERMOSTAT
EM. HT. RELAY 1
EM. HT. RELAY
CONTACT 1
EM. HT. RELAY 2
EM. HT. RELAY
CONTACT 2
EM.HT.
RELAY 3
2
COMPRESSOR
CONTACTOR 1
N.O. SWITCH — INSTALLER ADDED, TO LIGHT EM. HT. LED
WHEN COMPRESSOR OPERATION IS NOT NORMAL.
2