Armstrong G2D80CT - Gas Pressure and Altitude Adjustments; Manifold Pressure vs. Altitude Adjustments; Temperature Rise and High Altitude

# 45465K005 Page 23
The heating value of the gas can be obtained from the
local utility company.
For Propane Gas: The only check for the furnace rate is
to properly adjust the manifold pressure using a manom-
eter and the information provided in Table 3 on this page
or Table 4 on page 24. Typical manifold set point for
installations at altitudes from 0 to 4500 feet above sea
level is 10.0" W.C.
Temperature Rise
Check the temperature rise and, if necessary, adjust
blower speed to maintain temperature rise within the
range shown on the unit rating plate.
High Altitude
In both the United States and Canada, this furnace is
approved for operation at altitudes from 0 to 4500 feet above
sea level without any required modifications. From 4500 to
7500 feet, the gas manifold pressure needs to be adjusted
according to the information shown in Table 3 on this page
or Table 4 on page 24. To adjust the manifold pressure, refer
to the earlier section entitled Checking and Adjusting Gas
Input. For installations above 7500 feet, call Technical
Service at 1-800-448-5872 ext. 2610 for assistance.
x 3600 x
=
Cubic Feet Per RevolutionBTU/HR
INPUT # Seconds Per Revolution
Heating
Value
Make sure the final high- and low-fire manifold pres-
sures are within the allowable ranges specified above
for the gas being used.
Be sure to replace the inlet and outlet pressure tap plugs
after testing and/or adjusting gas input.
The furnace rate must be within +/- 2% of
the appliance rating input.
CAUTION
For Natural Gas: Check the furnace rate by observing the
gas meter, when available, making sure all other gas
appliances are turned off. The test hand on the meter
should be timed for at least one revolution. Note the
number of seconds for one revolution.
Table 3
Manifold Pressure vs. Altitude
G1D80BR and G1D80BT Models
* Consult local utility for actual heating value.
Furnace Input = Input Factor x Nameplate Input
Above 7500 feet, call Technical Services at 1-800-
448-5872 ext. 2610.
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