Allied A80UH1EX - Page 18

508031-02Issue 2135Page 18 of 29
2. After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in Table
18. Make manifold adjustment if necessary.
3. Shut unit o󰀨 and remove manometer as soon as an
accurate reading has been obtained.
4. Restart unit and check for any gas leaks. Seal any
leaks if found.
Altitude
Unit
Natural LP / Propane
Manifold Supply Manifold Supply
0 - 4,500 ft.
040 1.6 - 2.2
4.5 - 13.0
n/a n/a
060
3.0 - 3.8
3.4 - 3.8 11.0 - 13.0
080
100 n/a n/a
4,501 - 7,500 ft.
040 1.4 - 2.0
4.5 - 13.0
n/a n/a
060
2.5 - 3.3
2.5 - 3.3 11.0 - 13.0
080 n/a n/a
100 n/a n/a
Table 10. Supply Line and Manifold Pressure
(inches w.c.)
Proper Combustion
Furnace should operate a minimum 15 minutes with correct
manifold pressure and gas ow rate before checking
combustion. Take combustion sample beyond the ue
outlet and compare to Table 11. The maximum carbon
monoxide reading should not exceed 100 ppm.
Unit CO
2
% for Nat CO
2
% for LP
LP Conversion
Kit
040
6.5 - 7.5
n/a n/a
060
7.5 - 9.0
20P40
080 20P41
100 n/a n/a
Table 11.
High Altitude
Units may be installed at altitudes up to 7,500 ft. above
sea level. See Table 10 for de-rate manifold values. Units
installed at altitude of 4,501 - 7,500 feet require a pressure
switch change which can be ordered separately. Table 12
lists pressure switch requirements at high altitude.
The combustion air pressure switch is factory-set and
requires no adjustment.
Unit
High Altitude Pressure Switch
(4,501 - 7,500 ft)
Natural LP/Propane
040 20K91 N/A
060 No Change No Change
080 No Change N/A
100 20K91 N/A
Table 12.