Rheem A180CL25E - B. LP CONVERSION; C. ADJUSTING OR CHECKING FURNACE INPUT

17
B. LP CONVERSION
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.
!
WARNING
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)
TABLE 4
LP GAS PIPE CAPACITY TABLE (CU. FT./HR.)
Nominal
Iron Pipe
Size, Inches
10 20 30 40 50 60 70 80 90 100 125 150
275 189 152 129 114 103 96 89 83 78 69 63
567 393 315 267 237 217 196 182 173 162 146 132
1,071 732 590 504 448 409 378 346 322 307 275 252
2,205 1,496 1,212 1,039 913 834 771 724 677 630 567 511
3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976 866 787
6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811 1,606 1,496
1/2
3/4
1
1-1/4
1-1/2
2
Length of Pipe, Feet
Example (LP): Input BTU requirement of unit, 150,000
Equivalent length of pipe, 60 ft. = 3/4” IPS required.
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.
FIGURE 18A. HEAT EXCHANGER COMPONENT IDENTIFICATION
ST-A0886-29
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
2-STAGE
OPERATOR
INLET PRESSURE
TAP-1/8 NPT
GROUND
TERMINAL
LOW STAGE ADJUSTMENT
UNDER VENT CAP
HIGH STAGE ADJUSTMENT
UNDER VENT CAP