Honeywell MULTISTAGETHERMOSTATSAND T874H - Manual (Page 5)

69-0087—6 5
T874H,Q,W MULTISTAGE THERMOSTATS AND Q674B,C,G,L SUBBASES
1
L1
(HOT)
L2
T
W3
U
G
R
E
L
X
B
O
Y1
Y2
C815A OD THERMISTOR
AUX. HEAT RELAY
FAN RELAY
EM. HEAT RELAY COMPRESSOR
MONITOR
CHANGEOVER
RELAY (HEAT)
CHANGEOVER
RELAY (COOL)
COMPRESSOR
CONTACTOR 1
COMPRESSOR
CONTACTOR 2
EM.HEAT
AUTO
ON
FAN SWITCH
H1 ANTICIPATOR
H2 ANTICIPATOR
H3 ANTICIPATOR
RESET
FALL
FALL
FALL
H1
H3
H2
AUXILIARY
HEAT LED
(GREEN)
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
CONNECT CHANGEOVER RELAY TO 'O' TERMINAL FOR CHANGEOVER IN COOLING OR TO 'B' TERMINAL FOR CHANGEOVER IN HEATING.
M156A
C1 ANTICIPATOR
RISE
RISE
C2 ANTICIPATOR
C1
C2
EMERGENCY
HEAT LED
(RED)
CHECK LED
(RED)
HEAT
OFF
COOL
SYSTEM
SWITCH
2
1
2
THERMOSTAT SUBBASE SYSTEM COMPONENTS
1
2
3
4
5
6
8
9
10
11
12
Fig. 8. T874W/Q674L for three-stage heat and two-stage cool with outdoor reset and compressor monitor.