Allied Air Enterprises 92G1DF - Manual (Page 35)

506503-01 Page 35 of 44
Issue 1031
Gas Pressure Adjustment
Gas Flow (Approximate)
Furnace should operate at least 5 minutes before checking
gas flow. Determine time in seconds for two revolutions of
gas through the meter. (Two revolutions assures a more
accurate time.) Divide by two and compare to time in
Table 10 If manifold pressure matches Table 12 and rate
is incorrect, check gas orifices for proper size and restriction.
Remove temporary gas meter if installed.
NOTE: To obtain accurate reading, shut off all other gas
appliances connected to meter.
Supply Pressure Measurement
A threaded plug on the inlet side of the gas valve provides
access to the supply pressure tap. Remove the threaded
plug, install a field-provided barbed fitting and connect a
manometer to measure supply pressure. Replace the
threaded plug after measurements have been taken.
Manifold Pressure Measurement
1. Remove the threaded plug from the outlet side of the
gas valve and install a field provided barbed fitting.
Connect to a manometer to measure manifold pressure.
2. Start unit and allow 5 minutes for unit to reach steady
state.
3. While waiting for the unit to stabilize, observe the flame.
Flame should be stable and should not lift from burner.
Natural gas should burn blue.
4. After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in Table
12.
NOTE: Shut unit off and remove manometer as soon as
an accurate reading has been obtained. Take care to remove
barbed fitting and replace threaded plug.
Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas flow rate before checking
combustion. Take combustion sample beyond the flue outlet
and compare to the tables below. The maximum carbon
monoxide reading should not exceed 50 ppm.
NOTE: A natural to L.P./propane gas changeover kit is
necessary to convert this unit. Refer to the changeover kit
installation instruction for the conversion procedure.
Table 10
Table 13
Conversion Kit and Pressure Switch Requirements at Varying Altitudes
Pressure switch is factory set. No adjustment necessary. All models use the factory installed pressure switch from 0-4500 feet (0-1370 m).
Table 12
Manifold Pressure (Outlet) Inches w.c.
High Altitude Information
NOTE: In Canada, certification for installations at elevations
over 4500 feet (1372 m) is the jurisdiction of local authorities.
The manifold pressure may require adjustment to ensure
proper operation at higher altitudes. Refer to Table 12 for
proper manifold pressure settings at varying altitudes. Table
13 lists required pressure switch changes and conversion
kits at varying altitudes.
The combustion air pressure switches are factory set and
require no adjustment.
Table 11