60-24858 J.H. Rev. 3-01 www.hone

y

well.com

Home and Building Control Home and Building Control

Honeywell Honeywell Limited-Honeywell Limitée

1985 Douglas Drive North 35 Dynamic Drive

Golden Valley, MN 55422 Scarborough, Ontario

M1V 4Z9

Printed in U.S.A. on recycled
paper containing at least 10%
post-consumer paper fibers.
T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
Fig. 249. Schematic and hookup of T874C with Q674B. Used in heat pump applications.
C2
RISE
L1
(HOT)
L2 1
C1
RISE
H2
FALL
H1
FALL
M18622
H1 ANTICIPATOR
H2 ANTICIPATOR
C1 ANTICIPATOR
C2 ANTICIPATOR
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
FIELD WIRE JUMPER TO ALLOW SINGLE SYSTEM TRANSFORMER.
1
2
1
3
4
6
8
9
10
11 Y2
Y1
O
RH
B
W2
RC
G
W1
2
SYSTEM
SWITCH
HEAT
OFF
COOL
ON
AUTO
FAN
SWITCH
HEAT RELAY 1
FAN RELAY
HEAT RELAY 2
HEAT DAMPER
COOL DAMPER
COMPRESSOR CONTACTOR 1
COMPRESSOR CONTACTOR 2
THERMOSTAT SUBBASE SYSTEM COMPONENTS
SERVICE
LED (RED)
C
X