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Fig. 7—Internal schematic and typical wiring diagram for T874R and Q674L.
H1/C1
ANTICIPATOR
H1
C1
FALL
H2
H2
ANTICIPATOR
FALL
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
4. Turn over thermostat base and note the spring fingers
that engage the subbase contacts. Make sure the spring
fingers are not bent flat. Flat fingers prevent proper electrical
contact with the subbase.
5. Set the second stage heat anticipation indicator to
match the current rating of the controlled equipment. See
Heat Anticipator Setting section. The first stage heat antici-
pator and the cooling anticipator are nonadjustable.
6. Note the two tabs on the top inside edge of the
thermostat base. The tabs fit into corresponding slots on top
of the subbase. Mount the thermostat on the subbase.
7. Align the two captive mounting screws in the thermo-
stat base with the posts on the subbase (Fig. 9). Tighten both
screws. Do not overtighten screws because damage to
subbase posts can result.
FAN SWITCH
AUTO
ON
SYSTEM
SWITCH
EM. HT.
HEAT
OFF
COOL
5
R
EM.HT. RELAY
CONTACT
EM.HT. RELAY
CONTACT
W3
OUTDOOR
THERMOSTAT
DEFROST
RELAY
HEAT
RELAY 1
W2
DEFROST
RELAY
B
L
OPTIONAL COMP
FAILURE DEVICE
AUX. HEAT
LED (GREEN)
X2
X1
EM. HEAT
LED (RED)
E
G
LOW
COMPRESSOR
AMBIENT
CONTACTOR
CUTOFF
Y
COOL RELAY
O
Fig. 8—LED space location and adjustable lever
stops.
LED SPACE
L1
HOT
L2
1
HEAT
CONTACTOR 3
HEAT
CONTACTOR 2
HIGH LIMIT
SWITCH
REVERSING
VALVE
EM. HEAT
RELAY
FAN RELAY
HIGH
PRESSURE
SWITCH
M3685
TIGHTENING SCREW
ADJUSTABLE STOPS
M7557
60-1147-4
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