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Inlet Gas Pressure
Natural
Min. 5.0" W.C., Max. 10.0" W.C.
Min. 11.0" W.C., Max. 13.0" W.C.
Propane
Inlet Gas Pressure
Must be within the minimum and
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.
High Altitude Derate (U.S. Installations Only)
IMPORTANT NOTE: The gas/electric units naturally derate with al-
titude. Do not attempt to increase the fir ing rate by changing orifices
or increasing the manifold pressure. This can cause poor combustion
and equipment failure. At all altitudes, the manifold pressure 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: For altitudes above 2,000 feet, please refer to the gas/electric
package unit specification sheet for required kit(s).
Piping
IMPORTANT NOTE: To avoid possible unsatisfactory operation or
equipment damage due to under firing of equipment, do not undersize
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)
Length of
Nominal Black Pipe Size (inches)
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)
BTUH Furnace Input
CFH =
Heating Value of Gas (BTU/Cubic Foot)
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.
Maximum Value
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
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.
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)
Proper Piping Practice
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.
8
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