Lennox Allied Air A95UH1D User Manual

507270-03 Page 47 of 60Issue 1917
Gas Pressure Adjustment
Gas Flow (Approximate)
Table 10. Gas Meter Clocking Chart
Capacity
Seconds for One Revolution
Natural LP
1 cu ft
Dial
2 cu ft
Dial
1 cu ft
Dial
2 cu ft
Dial
-045 80 160 200 400
-070 55 110 136 272
-090 41 82 102 204
-110 33 66 82 164
-135 27 54 68 136
Natural - 1000 btu/cu ft LP - 2500 btu/cu ft
Furnace should operate at least 5 minutes before checking
gas ow. 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 orices 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
When testing supply gas pressure, use the 1/8” N.P.T.
plugged tap or pressure post located on the gas valve to
facilitate test gauge connection. See Figure 69. Check
gas line pressure with unit ring at maximum rate. Low
pressure may result in erratic operation or underre. High
pressure can result in permanent damage to gas valve or
overre.
On multiple unit installations, each unit should be checked
separately, with and without other units operating. Supply
pressure must fall within range listed in Table 12.
Manifold Pressure Measurement
1. Remove the threaded plug from the outlet side of
the gas valve and install a eld provided barbed
tting. 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
ame. 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 tting and replace threaded plug.
Proper Combustion
Furnace should operate minimum 15 minutes with correct
manifold pressure and gas ow rate before checking
combustion. Take combustion sample beyond the ue
outlet and compare to the tables below.
Table 11.
Capacity CO
2
% for Nat CO
2
% for L.P.
All 7.2 - 7.9 8.6 - 9.3
The maximum carbon monoxide reading should not exceed
100 ppm.
High Altitude Information
NOTE: In Canada, certication for installations at
elevations over 4500 feet (1371 m) is the jurisdiction of
local authorities.
Units may be installed at altitudes up to 10,000 ft. above
sea level. See Table 11 for derate manifold values. Units
installed at altitude of 7501 - 10,000 feet require an orice
change. Units installed at altitudes of 4,501 - 10,000 feet
(1371 -3048 m) may require a pressure switch change
which can be ordered separately.
Table 13 lists required pressure switch changes and orice
conversion kits at varying altitudes.
The combustion air pressure switches are factory set and
require no adjustment.
Table 12.
Manifold and Supply Line Pressure 0 - 10,000 ft.
Capacity Gas
Manifold Pressure in. w.g.
Supply Line Pressure
in. w.g.
0 - 10,000 ft.
0 - 4,500 ft.
4,501 - 5,500
ft.
5,501 - 6,500
ft.
6,501 - 7,500
ft.
7,501 -
10,000 ft.
All
Natural 3.5 3.3 3.2 3.1 3.5 4.5 13.0
LP / Propane 10. 9.4 9.1 8.9 10.0 11.0 13.0
NOTE: A natural to LP propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation
instruction for the conversion procedure.

Lennox Allied Air A95UH1D Specifications

General

Brand	Lennox
Model	Allied Air A95UH1D
Category	Furnace
Language	English