8
Is gas orifice the proper size for the gas in use?
Check manifold gas pressure at low fire (14 seconds
nominal) before it steps to normal high fire.
The compression fitting on the pilot tube must be tight.
Is the burner aligned perpendicular to the burner mounting
plate?
APPLICATION OF ALL WEATHER CAPS
In most cases, when a pilot is blown out during windy condi-
tions, an all weather cap will take care of this problem.
Extension(s) will also help (see Pilot Outage). See Accessory
Chart for part numbers.
All weather caps are used in areas of extreme cold (10° or
lower) for long periods of time. This causes ice to form and
block combustion air. Replace the standard crown with the
optional all weather cap. Follow instructions with the new all
weather cap. See Accessories section for part number.
a.
If the roof jack crown is covered or blocked with snow, the
furnace will not operate properly. If the home is located in
regions where snow accumulation exceeds 7” (HUD
snowload zones) use an external roof jack extension p/n
901937.
b.
M1 furnaces may be used with roof jacks as tall as 170”
(except M1M 056 models, which are limited to 120”).
Internal roof jack extensions (p/n 901935 - 10”, p/n 903107
- 18”) can be used to increase roof jack height. All connec-
tions inside the home must be made below the ceiling.
ELECTRICAL WIRING
Line Voltage Wiring (See Figure 15)
The line voltage (115 volt) to the furnace must be supplied
from a dedicated circuit containing the correct fuse or circuit
breaker for the furnace. See Table 5. An electrical switch
should be readily accessible from and within sight of the
furnace. All line voltage connections must be made within the
junction box located within the furnace.
The furnace cabinet must have an uninterrupted, unbroken
ground to minimize injury should an electrical fault condition
occur. The controls used in this furnace also require an earth
ground to cooperate properly. Acceptable methods for ground-
ing are electrical wire or conduit approved for electrical ground
service. Do not use gas piping as an electrical ground.
NOTE: Proper line voltage polarity must be maintained in
order for the control system to operate correctly. Verify
that the incoming neutral line is connected to the white
wire and the incoming "hot" line is connected to the black
wire in the furnace junction box. This furnace will not
operate unless polarity and ground are properly con-
nected. (See Figure 16).
Never use gas lines as ground.
To determine polarity, the incoming power supply should be
checked. The "Hot" lead will read 115V to ground. The
"neutral" should read 0V to ground.
Figure 2.
Figure 3.
Figure 1. Roof Jack Assemblies
Roof Jack
Flat Roof
Ceiling Cavity
Ceiling
Flue Pipe
Combustion
Air Pipe
Flashing
This joint
may be
above ceiling
"A"
"B"
56" or 76"
Furnace
5/12 ROOF SLOPE
2
SLANT DECK
/12
1 2
ROOF JACK WITH
2
FLASHING
/12 SLANT
1 2
ROOF JACK
SLANT DECK
FLASHING
PITCHED
ROOF
CEILING
CEILING CAVITY
ROOF OPENING
CEILING OPENING
"X" (SEE TABLE 1)
6
