Gas Pressure Measurement; Proper Combustion; High Altitude - Lennox ELITE EL195UHE Installation Instructions Manual

Gas Pressure Adjustment
Gas Flow (Approximate)
TABLE 11
GAS METER CLOCKING CHART
Seconds for One Revolution
Natural
EL195
Unit 1 cu ft
Dial
-045 80
-070 55
-090 41
-110 33
-135 27
Natural-1000 btu/cu ft
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
11 below. 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
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 59. Check gas
line pressure with unit firing at maximum rate. Low pres­
sure may result in erratic operation or underfire. High pres­
sure can result in permanent damage to gas valve or over­
fire.
On multiple unit installations, each unit should be checked
separately, with and without units operating. Supply pres­
sure must fall within range listed in table 12.
Check Manifold Pressure
After supply pressure has been checked and adjusted,
check manifold pressure. Move pressure gauge to outlet
pressure tap located on unit gas valve (GV1).
Checks of manifold pressure are made as verification of
proper regulator adjustment.
IMPORTANT
For safety, connect a shut‐off valve between the
manometer and the gas tap to permit shut off of
gas pressure to the manometer.
Follow the steps below. Gas manifold Kit 10L34 provides
additional components if needed.
LP
2 cu ft 1 cu ft 2 cu ft
Dial Dial DIAL
160 200 400
110 136 272
82 102 204
66 82 164
54 68 136
LP-2500 btu/cu ft
1 - Connect the test gauge positive side "+" to manifold
pressure tap on gas valve.
2 - Tee into the gas valve regulator vent hose and con­
nect to test gauge negative "-".
3 - Start unit and let run for 5 minutes to allow for steady
state conditions.
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.
Supply Line and Manifold Pressure (inches w.c.)
Unit Fuel
All Nat
All LP/Propane

Proper Combustion

Furnace should operate minimum 15 minutes with correct
manifold pressure and gas flow rate before checking com­
bustion. Take combustion sample beyond the flue outlet
and compare to the tables below.
EL195
Unit
-045
-070
-090
-110
-135
The maximum carbon monoxide reading should not exceed 50 ppm.
High Altitude Information
NOTE - In Canada, certification for installations at eleva­
tions over 4500 feet (1372 m) is the jurisdiction of local au­
thorities.
Units may be installed at altitudes up to 10,000 ft. above
sea level. See table 15 for de-rate manifold values. Units
installed at altitude of 7501 - 10,000 feet require an orifice
change. Units installed at altitude of 4501 - 10,000 feet re­
quire a pressure switch change which can be ordered sep­
arately. Table 15 lists conversion kit and pressure switch
requirements at varying altitudes.
The combustion air pressure switch is factory-set and re­
quires no adjustment.
Page 44
TABLE 12
Manifold
Line Pressure
Pressure
3.5 4.5 - 10.5
10.0 11.0 - 13.0
TABLE 13
CO % CO %
2 For Nat 2
7.2 - 8.2 8.6 - 9.6
For LP