Honeywell Q674 Installation Instructions Manual page 3

2. Carefully remove and discard the polystyrene packing
insert that protects the mercury switches during shipment.
3. If LED indication (EM.HT., CHECK, etc.) is to be used
with the Q674 Subbase, install the preprinted insert under the
thermostat set point scale (Fig. 8). To install, push both
thermostat set point levers to the far ends of the thermostat. Use
index finger to gently pull out the plastic set point scale about
1/4 in. [6 mm]. Drop insert into recessed area behind set point
scale so that selected LEDs show. Make sure insert is com-
pletely seated in recessed area. Let set point scale pop back, and
set levers to desired positions.
Fig. 5—Internal schematic and typical wiring diagram for T874N and Q674C.
H1
ANTICIPATOR
FALL
H1
FALL
H2
H2 ANTICIPATOR
C1
ANTICIPATOR
C1
CO
RISE
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS
REQUIRED.
Fig. 4—Wiring connections.
FOR STRAIGHT
INSERTION–
STRIP 5/16 in. [8 mm]
FAN
SWITCH
AUTO
ON
SYSTEM
SWITCH
OFF
AUTO
3
BARRIER
SUBBASE TERMINAL SCREW
DEFROST RELAY
CONTACT
W1
OUTDOOR
THERMOSTAT
EM. HT. RELAY
CONTACT
W3
EM. HT. RELAY
CONTACT
G
FAN RELAY
R
W2
HEAT
RELAY 1
X
CHECK
LED
(GRN)
OPTIONAL
COMPRESSOR
L
FAILURE
DEVICE
Y
FOR WRAPAROUND–
STRIP 7/16 in. [11 mm]
M928
L1
(HOT)
L2
1
REVERSING
RELAY
HEAT
RELAY 2
HEAT
RELAY 3
COMPRESSOR
CONTACTOR
M1860
60-1147-4