Rheem A180CL25E Installation Instructions Manual page 17

B. LP CONVERSION
! WARNING
THIS UNIT IS EQUIPPED AT THE
FACTORY FOR USE ON NATURAL GAS
ONLY. CONVERSION TO LP GAS
REQUIRES A SPECIAL KIT SUPPLIED
BY THE DISTRIBUTOR OR
MANUFACTURER. MAILING
ADDRESSES ARE LISTED ON THE
FURNACE RATING PLATE, PARTS LIST
AND WARRANTY. FAILURE TO USE
THE PROPER CONVERSION KIT CAN
CAUSE FIRE, CARBON MONOXIDE
POISONING, EXPLOSION, PERSONAL
INJURY, PROPERTY DAMAGE OR
DEATH.
Convert the unit to use liquefied petroleum
(LP) gas by replacing with the stem/spring
assembly supplied in the conversion kit.
The LP gas valve maintains the proper
manifold pressure for LP gas. The correct
burner LP orifices are included in the kit.
See Figure 18A for component locations.
NOTE: Order the correct LP conversion kit
from the furnace manufacturer. See
Conversion Kit Index shipped with unit
for proper LP kit number. Furnace
conversion to LP gas must be
performed by a qualified technician.
C. ADJUSTING OR CHECKING
FURNACE INPUT
– Natural Gas Line Pressure 5" - 10.5"
W.C.
– LP Gas Line Pressure 11" - 13" W.C.
– Natural Gas Manifold Pressure 3.5"
W.C
– LP Gas Manifold Pressure - 10" W.C.
FIGURE 18A. HEAT EXCHANGER COMPONENT IDENTIFICATION
LP GAS PIPE CAPACITY TABLE (CU. FT./HR.)
Maximum capacity of pipe in thousands of BTU per hour of undiluted liquefied petroleum gases
(at 11 inches water column inlet pressure).
(Based on a Pressure Drop of 0.5 Inch Water Column)
Nominal
Iron Pipe
10
Size, Inches
1/2 275
3/4 567
1 1,071
1-1/4 2,205 1,496 1,212 1,039
1-1/2 3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023
2 6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496
Example (LP): Input BTU requirement of unit, 150,000
Equivalent length of pipe, 60 ft. = 3/4" IPS required.
Supply and manifold pressure taps are
located on the gas valve body 1/8" N.P.T.
and on the manifold. See Figure 18B.
Use a properly calibrated manometer gauge
for accurate gas pressure readings.
FIGURE 18B. HONEYWELL VR8305Q4120 TWO STAGE GAS VALVE
OUTLET PRESSURE
TAP-1/8 NPT
GROUND
TERMINAL
LOW STAGE ADJUSTMENT
UNDER VENT CAP
TABLE 4
Length of Pipe, Feet
20 30 40 50 60 70 80
189 152 129 114 103 96 89
393 315 267 237 217 196 182
732 590 504 448 409 378 346
913 834 771 724
Only small variations in the gas flow should
be made by means of the pressure
regulator adjustment. Furnaces functioning
on LP gas must be set 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.
ST-A0886-29
90 100 125 150
83 78 69 63
173 162 146 132
322 307 275 252
677 630 567 511
976 866 787
2-STAGE
OPERATOR
INLET PRESSURE
TAP-1/8 NPT
HIGH STAGE ADJUSTMENT
UNDER VENT CAP
17