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Inlet Gas Pressure
Natural
Min. 5.0" W.C., Max. 10.0" W.C.
Propane
Min. 11.0" W.C., Max. 13.0" W.C.
Inlet Gas Pressure Must Not Exceed the Maximum Value Shown in Table
Above.
The minimum supply pressure should not vary from that shown in
the table above because this could prevent the unit from having
dependable ignition. In addition, gas input to the burners must not
exceed the rated input shown on the rating plate. Overfiring of the
unit could result in premature heat exchanger failure.
H
A
D
IGH
LTITUDE
ERATE
IMPORTANT NOTE: The gas/electric units naturally derate with al-
titude. Do not attempt to increase the firing rate by changing ori-
fices or increasing the manifold pressure. This can cause poor com-
bustion and equipment failure. At all altitudes, the manifold pres-
sure must be within 0.3 inches W.C. of that listed on the nameplate
for the fuel used. At all altitudes and with either fuel, the air tempera-
ture rise must be within the range listed on the unit nameplate.
Refer to the Installation Manual provided with the LP kit for conver-
sion from natural gas to propane gas and for altitude adjustments.
NOTE: Up to 2,000 feet, no changes are required; above 2,000 feet,
please refer to the gas/electric package unit specification sheets
for required kit(s).
P
IPING
IMPORTANT NOTE: To avoid possible unsatisfactory operation or
equipment damage due to under firing of equipment, do not un-
dersize the natural/propane gas piping from the meter/tank to the
unit. When sizing a trunk line, include all appliances on that line
that could be operated simultaneously.
The rating plate is stamped with the model number, type of gas
and gas input rating. Make sure the unit is equipped to operate on
the type of gas available. The gas line installation must comply
with local codes, or in the absence of local codes, with the latest
edition of the National Fuel Gas Code NFPA 54/ANSI Z223.1.
Natural Gas Connection
Natural Gas Capacity of Pipe
in Cubic Feet of Gas Per Hour (CFH)
Nominal Black Pipe Size (inches)
Length of
Pipe in Feet
1/2
10
132
20
92
30
73
40
63
50
56
60
50
70
46
80
43
90
40
100
38
Pressure = .50 PSIG or less and Pressure Drop of 0.3" W.C. (Based
on 0.60 Specific Gravity Gas)
B TU H F urn ace Inp ut
CF H =
H eating V alu e of G as (B T U/C ubic Fo ot)
Refer to the Proper Piping Practice drawing for the general layout
at the unit. The following rules apply:
1. Use black iron pipe and fittings for the supply piping. The
use of a flex connector and/or copper piping is permitted
as long as it is in agreement with local codes.
2. Use pipe joint compound on male threads only. Pipe joint
compound must be resistant to the action of the fuel used.
3. Use ground joint unions.
4. Install a drip leg to trap dirt and moisture before it can enter
the gas valve. The drip leg must be a minimum of three
inches long.
(U.S. I
O
NSTALLATIONS
NLY
3/4
1
1 1/4
1 1/2
278
520
1050
1600
190
350
730
1100
152
285
590
980
130
245
500
760
115
215
440
670
105
195
400
610
96
180
370
560
90
170
350
530
84
160
320
490
79
150
305
460
5. Use two pipe wrenches when making connection to the
gas valve to keep it from turning.
6. Install a manual shut-off valve in a convenient location
(within six feet of unit) between the meter and the unit.
7. Tighten all joints securely.
8. The unit must be connected to the building piping by one
of the following methods:
•
Rigid metallic pipe and fittings
•
Semirigid metallic tubing and metallic fittings (Aluminum
alloy tubing must not be used in exterior locations)
•
Listed gas appliance connectors used in accordance with
)
the terms of their listing that are completely in the same
room as the equipment
•
In the prior two methods above the connector or tubing
must be protected from physical and thermal damage.
Aluminum alloy tubing and connectors must be coated to
protect against external corrosion when in contact with
masonry, plaster or insulation or are subject to repeated
wettings by liquids (water - not rain water, detergents or
sewage)
GROMMET
NOTE: The unit gas supply entrance is factory sealed with plugs.
Keep plugs in place until gas supply is ready to be installed. Once
ready, replace the plugs with the supplied grommets and install gas
supply line.
7
GROUND JOINT UNION
(INSTALLED AHEAD OF GAS VALVE)
Proper Piping Practice
MANUAL
SHUT-OFF
VALVE
DRIP LEG
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