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31-5000737 Rev. 0
Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas flow rate before checking
combustion. Take combustion sample beyond the flue
outlet and compare to Table 9.
Capacity
CO
2
% for Nat
CO
2
% for L.P.
All
7.2 - 7.8
7.5 - 9.0
The maximum carbon monoxide reading should not exceed
100 ppm.
Table 9.
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 10 for manifold pressure and Table 11 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. w.g.
Supply Line Pressure
in. w.g.
0-2,000 ft.
2,001-4,500 ft.
4,501-7,500 ft.
7,501-10,000 ft.
Min.
Max
045
Natural
3.5
3.2
3.0
3.5
4.5
13.0
LP / Propane
10.5
10.0
10.0
10.0
11.0
070
Natural
3.5
3.2
2.8
3.5
4.5
LP / Propane
10.0
10.0
10.0
10.0
11.0
090
Natural
3.5
3.2
2.7
3.5
4.5
LP / Propane
10.0
10.0
9.6
10.0
11.0
110
Natural
3.5
3.5
3.0
3.5
4.5
LP / Propane
10.0
10.0
9.6
10.0
11.0
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 10. Manifold and Supply Line Pressure 0-10,000 ft.
Capacity
0-4,600 ft
4,601 - 7,600 ft
7,601 - 10,000 ft
Pressure
1
Switch Kit
Natural to
LP/Propane
Orifice Kit
Pressure
1
Switch Kit
Natural to
LP/Propane
Orifice Kit
Pressure
1
Switch Kit
Natural to
LP/Propane
Orifice Kit
045
As Shipped
(-0.65” w.c.)
11K50
2
(0.034”)
80W52
(-0.60” w.c.)
11K50
2
(0.034”)
80W51
(-0.55” w.c.)
11K45
2
(0.032”)
070
As Shipped
(-0.68” w.c.)
090
As Shipped
(-0.65” w.c.)
80W57
(-0.65” w.c.)
80W52
(-0.60” w.c.)
110
As Shipped
(-0.68” w.c.)
80W52
(-0.60” w.c.)
80W51
(-0.55” w.c.)
1 Minimum allowable set points for this altitude range. Application of a Pressure Switch with lower set point (less negative / closer to zero) is not permitted.
2 Kit contains burner orifices and gas valve regulator spring(s).
Table 11.
Burner Orifice Conversion Kits at Varying Altitudes
