035-17477-002 Rev. D (1202)
12
Unitary Products Group
NOTE:
An accessible manual shutoff valve must be installed
upstream of the furnace gas controls and within 6 feet of the
furnace.
NOTE:
A 1/8” NPT plug is included in the inlet side of the gas
valve for measuring incoming gas pressure.
The furnace must be isolated from the gas supply piping sys-
tem by closing its individual external manual shutoff valve
during any pressure testing of the gas supply piping system
at pressures equal to or less than 1/2 psig (3.48 kPa).
The furnace and its individual shutoff valve must be discon-
nected from the gas supply piping system during any pres-
sure testing of that system at test pressures in excess of 1/2
psig (3.48 kPa)
.
ELECTRICAL POWER CONNECTION
Field wiring to the unit must conform to and be grounded in
accordance with the provisions of the National Electrical
Code ANSI/NFPA No. 70-latest edition, Canadian Electric
Code C22.1 Part 1 - (latest edition) and/or local codes. Elec-
tric wires which are field installed shall conform with the tem-
perature limitation for 63°F/35°C rise wire when installed in
accordance with instructions. Refer the rating plate or Physi-
cal and Rating Data Tables in these instructions for specific
furnace electrical data.
Provide a power supply separate from all other circuits. Install
overcurrent protection and disconnect switch per local/
national electrical codes. The switch should be close to the
unit for convenience in servicing. With the disconnect switch
in the OFF position, check all wiring against the unit wiring
label. Also, see the wiring diagram in this instruction.
NOTE:
The furnace’s control system depends on correct
polarity of the power supply and a proper ground connection.
Refer to the “FURNACE CONTROL DIAGNOSTICS” on
page 36 for symptoms of reversed power supply polarity.
Connect the power supply as shown on the unit wiring label
on the inside of the blower compartment door. The black fur-
nace lead must be connected to the L1 (hot) wire from the
power supply. The white furnace lead must be connected to
neutral. Also, the green equipment ground wire must be con-
nected to the power supply ground.
Remove the screws retaining the wiring box cover. Route the
power wiring through the opening in the unit into the junction
box with a conduit connector or other proper connection.
Make wiring connections and replace the wiring box cover
and screws. Refer to Figures 11or 12.
An alternate wiring method is to use a field provided 2 x 4 box
and cover on the outside of the furnace. Route the furnace
leads into the box using a protective bushing where the wires
pass through the furnace pane.
INLET GAS PRESSURE RANGE
Natural Gas
Propane (LP)
Minimum
4.5 In. W.C.
11 In. W.C.
Maximum
13.9 In. W.C.
13.9 In. W.C.
FIGURE 10 :
Gas Piping
Compounds used on threaded joints of gas piping
must be resistant to the action of liquefied petro-
leum gases. After connections are made, leak-test
all pipe connections.
After all gas piping connections are completed,
leak test all joints, fittings and furnace connections
with rich soap and water solution, commercially
available bubble type leak detection fluid, or other
approved means.
Do not use an open flame or other source of
ignition for leak testing.
EXTERNAL MANUAL
SHUTOFF VALVE
TO GAS
SUPPLY
TO GAS
SUPPLY
DROP
LEG
GROUND JOINT UNION
MAY BE INSTALLED
INSIDE OR OUTSIDE UNIT.
Never apply a pipe wrench to the body of the com-
bination automatic gas valve. A wrench must be
placed on the projection or wrench boss of the
valve when installing piping to it.
Use copper conductors only.
