T874 MULTISTAGE THERMOSTATS AND Q674 SUBBASES
60-24858104
Fig. 59. Schematic and hookup of T874A with Q674Q. Used in fan coil applications. Fig. 60. Schematic and hookup of T874C with Q674N. Used in evaporative cooler applications.
L1
(HOT)
L2
1
K2 RELAY
SYSTEM
SWITCH
ON
HIGH
H1
ANTICIPATOR
H1 FALL
1POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
M3729
HEAT
COOL
FAN
SWITCH
R
COMPRESSOR
CONTACTOR
Y1
B
O
G1
MED G2
K1 RELAY
W1
C1
ANTICIPATOR
C1 RISE
HEAT
RELAY 1
OFF
K2
K1
K2
K1
K2
HI LOMED
3 SPEED FAN
SCHEMATIC
LO L2 L1
THERMOSTAT SUBBASE SYSTEM COMPONENTS
1
4
8
9
10
L1
(HOT)L2 1
H2 ANTICIPATOR
M2863
H1 ANTICIPATOR
C1 ANTICIPATOR
FALL
H1
R
W2
W1
G
ELEC. HT. RELAY
FAN RELAY
COOL RELAY
CONTACT
1POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
AUTO
ON
FAN
SWITCH
SYSTEM
SWITCH
EVAP
HEAT
OFF
COOL
CHANGEOVER
VALVE
COMPRESSOR
CONTACTOR
EVAPORATOR
RELAY
RISE
C1
FALL
H2
Y1
B
Y2
THERMOSTAT SUBBASE SYSTEM COMPONENTS
1
4
6
8
9
10