508145-01
Page 30 of 36
Issue 2128
6. Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Turn the supply
and manifold 3/32” hex screw one revolution back into
the gas valve.
7. Start unit and check for gas leaks. Seal if any found.
Proper Combustion
Furnace should operate a minimum 15 minutes with correct
manifold pressure and gas flow rate before checking
combustion. Table 14 shows acceptable combustion for
all 80G2DFE
models.
The maximum carbon monoxide
reading should not exceed 100 ppm.
Capacity
CO
2
% for Nat
CO
2
% for LP
High Fire
6.8 - 7.4
7.5 - 9.0
Low Fire
4.2 - 5.7
5.0 - 6.0
Table 14.
High Altitude
The manifold pressure may require adjustment and
combustion air pressure switch may need replacing to
ensure proper combustion at higher altitudes. Refer to
Table 15 for manifold pressure and Table 16 for pressure
switch change and gas conversion kits.
For safety, shut unit off and remove manometer as soon
as an accurate reading has been obtained. Take care to
replace pressure tap plug.
IMPORTANT
Capacity
Gas
Manifold Pressure
in. wg. 0 - 4,500 ft.
Manifold Pressure
in. wg. 4,501 - 7,500 ft.
Manifold Pressure
in. wg. 7,501 - 10,000 ft.
2
Supply Line Pressure
in. wg.
Low Fire High Fire
Low Fire
High Fire
Low Fire
High Fire
Min.
Max.
070
Natrual
1.7
3.5
1.5
3.2
1.7
3.5
4.5
13.0
LP/Propane
3
4.5
10.0
4.5
10.0
4.5
10.0
11.0
13.0
090
Natrual
1.7
3.5
1.5
3.0
1.7
3.5
4.5
13.0
LP/Propane
3
4.5
10.0
4.5
10.0
4.5
10.0
11.0
13.0
1.
This is the only permissible derate for these units.
2.
Natural gas high altitude orifice kit required.
3.
A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for
the conversion procedure.
NOTE - Units may be installed at altitudes up to 4500 ft. above sea level without modifications.
Table 15. Manifold Pressure and Line Pressure at Various Altitudes
Capacity
High Altitude Pressure Switch Kit
High Altitude
Natural Gas
Oririce Kit
Natural to LP/Propane Kit
LP/Propane to
Natural Kit
0 - 4,500 ft.
4,501 - 7,500 ft. 7,501 - 10,000 ft. 7,501 - 10,000 ft.
0 - 7,500 ft.
7,501 - 10,000 ft.
0 - 7,500 ft.
All
No Change
91W53
73W35
51W01
11K48
11K47
77W10
NOTE: A natural to LP/Propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the
conversion procedure.
Table 16.
Orifice Kits and Pressure Switch Kits at Various Altitudes
