Rheem RGPH Installation Instructions Manual page 28

Furnaces for use on LP gas, the LP
gas supply pressure must be set
between 11.0 and 14.0 W.C. by
means of the tank or branch supply
regulators. The furnace manifold
pressure should be set at 10 W.C. at
the gas control valve. For elevations
up to 8,000 feet, rating plate input
ratings apply. For high altitudes
(elevations 8,000 and over) and for
any necessary major changes in the
gas flow rate the orifice spud must be
changed.
To change orifice spuds:
1. Shut off the manual main gas valve
and remove the gas manifold.
2. Replace the orifice spuds.
3. Reassemble in reverse order.
4. Turn the gas supply back on and
check for proper operation and
manifold pressure.
Check of input is important to prevent
over firing of the furnace beyond its
design-rated input. NEVER SET
INPUT ABOVE THAT SHOWN ON
THE RATING PLATE.
To check furnace input:
1. Make certain that all other gas
appliances are shut off, with the
exception of pilot burners.
2. Start the furnace
3. Time the meter to measure the time
required to burn one cubic foot of
gas.
4. Use Table 4 to determine input rate.
28
ORIFICE SIZING CHART
RATING PLATE
INPUT
BTU/HR 0 TO 7,999 FT.
HEATING VALUE @ 1,000 BTU/FT
NATURAL GAS
45,000
50,000
67,500
75,000
100,000
125,000
150,000
HEATING VALUE @ 2,475 BTU/FT
L.P. GAS
45,000
50,000
67,500
75,000
100,000
125,000
150,000
ORIFICE SIZING CHART (CANADA)
RATING PLATE
INPUT
BTU/HR 0 TO 1,999 FT.
HEATING VALUE @ 1,000 BTU/FT
NATURAL GAS
45,000
50,000
67,500
75,000
100,000
125,000
150,000
HEATING VALUE @ 2,475 BTU/FT
L.P. GAS
45,000
50,000
67,500
75,000
100,000
125,000
150,000
ELEVATION
8,000 FT. AND ABOVE
3 , SPECIFIC GRAVITY 0.62
MANIFOLD PRESSURE @ 3.5 W.C.
43
42
43
42
42
42
42
3 , SPECIFIC GRAVITY 1.52/
MANIFOLD PRESSURE @ 10 W.C.
54
54
54
54
54
54
54
ELEVATION
2,000 FT. TO 4,500 FT.
3 , SPECIFIC GRAVITY 0.62
MANIFOLD PRESSURE @ 3.5 W.C.
43
42
43
42
42
42
42
3 , SPECIFIC GRAVITY 1.52/
MANIFOLD PRESSURE @ 10 W.C.
54
54
54
54
54
54
54
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43
45
43
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43
43
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