4
Refer to the Roof Curb Installation Instructions for proper
curb installation. Curbing must be installed in compliance
with the National Roofing Contractors Association Manual.
Lower unit carefully onto roof mounting curb. While rigging
unit, center of gravity will cause condenser end to be lower
than supply air end.
If using a fork lift, see Figure 1 for location of fork prongs.
Make certain prongs support unit weight.
Fork Lift From
Back Of Unit
Figure 1
Rigging
IV. Gas Piping
IMPORTANT NOTE: This unit is factory set to operate on
natural gas at the altitudes shown on the rating plate.
WARNING
To prevent death, personal injury or property
damage when either using propane gas
alone or at higher altitudes, obtain and
install the proper conversion kit(s). Failure
to do so can result in unsatisfactory
operation and/or equipment damage. High
altitude kits are for U.S. installations only
and are not approved for use in Canada.
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.
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.
Table 1
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 (US. INSTALLATIONS
ONLY)
IMPORTANT NOTE: The gas/electric units will naturally
derate itself with altitude. Do not attempt to increase the
firing 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 “Specification Sheet” 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 name-
plate.
Refer to the “Specification Sheet” for kits for conversion
from natural gas to propane gas and for altitude adjust-
ments.
PIPING
IMPORTANT NOTE: To avoid possible unsatisfactory op-
eration or equipment damage due to under firing of equip-
ment, do not undersize the natural/propane gas piping from
the meter/tank to the unit. When sizing a trunk line as shown
in Table 2, 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 (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
3/4
1
1 1/4
1 1/2
10
132
278
520
1050
1600
20
92
190
350
730
1100
30
73
152
285
590
980
40
63
130
245
500
760
50
56
115
215
440
670
60
50
105
195
400
610
70
46
96
180
370
560
80
43
90
170
350
530
90
40
84
160
320
490
100
38
79
150
305
460
Pressure = .50 PSIG or less and Pressure Drop of 0.3" W.C. (Based
on 0.60 Specific Gravity Gas)
CFH =
BTUH Furnace Input
Heating Value of Gas (BTU/Cubic Foot)
Table 2