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WIRE THE SUBBASE
Disconnect power supply before beginning installation
to prevent electrical shock or equipment damage. All wiring
must comply with local electrical codes and ordinances.
Follow equipment manufacturer's wiring instructions when
available. To wire the subbase, proceed as follows:
1. Connect the system wires to the subbase. See Figs. 5
through 11. A letter code is located near each terminal for
identification. The terminal barrier permits straight or con-
ventional wraparound wiring connections. See Fig. 4.
2. Firmly tighten each terminal screw.
3. Fit wires as close as possible to the subbase. Push
excess wire back into the hole.
4. Plug the hole with nonflammable insulation to pre-
vent drafts from affecting the thermostat.
Fig. 5—T874D/Q674A in standard heating/cooling system.
FALL
H1
H1 ANTICIPATOR
H2 ANTICIPATOR
FALL
H2
RISE
C1
C1
ANTICIPATOR
C2 ANTICIPATOR
RISE
C2
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
2
JUMPER RC, RH FOR SINGLE TRANSFORMER.
3
OPTIONAL CHECK-LITE ON SOME MODELS.
Fig. 4—Wiring connections.
FOR STRAIGHT
INSERTION–
STRIP 5/16 in. [8 mm]
FAN
SWITCH
AUTO
ON
SYSTEM
SWITCH
HEAT
AUTO
COOL
3
BARRIER
SUBBASE TERMINAL SCREW
CHECK
3
RH
HEAT RELAY 1
W1
HEAT RELAY 2
W2
X1
2
G
FAN RELAY
Y2
COMPRESSOR
CONTACTOR 2
Y1
COMPRESSOR
CONTACTOR 1
RC
FOR WRAPAROUND–
STRIP 7/16 in. [11 mm]
M928
L1
(HOT)
1
L2
L2
1
L1
(HOT)
M932A
60-1227—1
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