Specifications

035-17377-000 REV A (0201)
Unitary Products Group 43
GAS FURNACE OPERATION
BURNERS/ORIFICES INSPECTION/SERVICING
Before checking or changing burners, pilot or orifices,
CLOSE MAIN MANUAL SHUT-OFF VALVE AND SHUT OFF
ALL POWER TO THE UNIT.
1. Open the union fitting just upstream of the unit gas valve
and downstream from the main manual shut-off valve in
the gas supply line.
2. Remove the screws holding each end of the manifold to
the manifold supports.
3. Disconnect wiring to the gas valves and spark igniter(s).
Remove the manifold & gas valve assembly. Orifices
can now be inspected and/or replaced.
To service burners, complete step 4.
4. Remove the heat shield on top of the manifold supports.
Burners are now accessible for inspection and/or
replacement.
NOTE:
Reverse the above procedure to replace the assem-
blies.
Make sure that burners are level and seat at the rear of the
gas orifice.
LIGHTING THE MAIN BURNERS
1. Turn “OFF” electric power to unit.
2. Turn room thermostat to lowest setting.
3. Turn gas valve counter-clockwise to “ON” position (See
Figure 19).
4. Turn “ON” electric power to unit.
This furnace is equipped with an automatic ignition
system. Do not attempt to manually light the burn-
ers.
TABLE 49: GAS APPLICATION
Unit
Input (MBH)
Output
(MBH)
Temp Rise
(
°
F)
Size Opt.
078
10
120 96 20-50
15
180 144 35-65
090
10
120 96 15-45
15
180 144 30-60
102
10
120 96 10-40
15
180 144 25-55
120
15
180 144 20-50
20
240 192 30-60
150
15
180 144 10-40
20
240 192 20-50
FIGURE 21 : TYPICAL FLAME
FIGURE 22 : TYPICAL GAS VALVE