Gas Pressure Measurement - Lennox ELITE Series Installation Instructions Manual

WHITE RODGERS GAS VALVE
MANIFOLD
PRESSURE TAP
INLET PRESSURE POST
GAS VALVE SHOWN IN ON POSITION
FIGURE 32
10- Turn on all electrical power to to the unit.
11- Set the thermostat to desired setting.
NOTE - When unit is initially started, steps 1 through
11 may need to be repeated to purge air from gas
line.
12- If the appliance will not operate, follow the
instructions "Turning Off Gas to Unit" and call your
service technician or gas supplier.
Turning Off Gas to Unit
1 - Set the thermostat to the lowest setting.
2 - Turn off all electrical power to the unit if service is to
be performed.
3 - Remove the upper access panel.
4 - Move switch on gas valve to OFF. Do not force.
5 - Replace the upper access panel.
Failure To Operate
If the unit fails to operate, check the following:
1 - Is the thermostat calling for heat?
2 - Are access panels securely in place?
3 - Is the main disconnect switch closed?
4 - Is there a blown fuse or tripped circuit breaker?
5 - Is the filter dirty or plugged? Dirty or plugged filters
will cause the limit control to shut the unit off.
6 - Is gas turned on at the meter?
7 - Is the manual main shut-off valve open?
8 - Is the gas valve ON/OFF switch in the ON position?
9 - Is the unit ignition system in lock out? If the unit locks
out again, call the service technician to inspect the
unit for blockages.
10 - Is pressure switch closed? Obstructed flue will
cause unit to shut off at pressure switch. Check flue
and outlet for blockages.
11 - Are flame rollout switches tripped? If flame rollout
switches are tripped, call the service technician for
inspection.
HIGH FIRE
LOW FIRE
ADJUSTMENT
ADJUSTMENT
(under cap)
(under cap)
Gas Pressure Adjustment
Gas Flow (Approximate)
GAS METER CLOCKING CHART
Unit
Input
1 cu ft
Dial
-045 80
-070 55
-090 41
-110 33
Natural-1000 btu/cu ft LP-2500 btu/cu ft
Furnace should operate at least 5 minutes before check-
ing gas flow. Determine time in seconds for two revolu-
tions 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 13
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
An inlet post located on the gas valve provides access
to the supply pressure. See figure 32. Back out the 3/32"
hex screw one turn, connect a piece of 5/16" tubing and
connect to a manometer to measure supply pressure. See
table 13 for supply line pressure.
Manifold Pressure
A manifold pressure tap located on the gas valve provides
access to the manifold pressure. See figure 32. Back out
the 3/32 hex screw one turn, connect a piece of 5/16"
tubing and connect to a manometer to measure manifold
pressure.
NOTE - Pressure test adapter kit (10L34) is available from
Lennox to facilitate manifold pressure measurement.
1 - Connect test gauge to manifold pressure tap (figure
32) gas valve.
2 - Ignite unit on low fire and let run for 5 minutes to
allow for steady state conditions.
3 - After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in
table 13.
4 - If necessary, make adjustments. Figure 32 shows
location of high fire and low fire adjustment screw.
5 - Repeat steps 2, 3 and 4 on high fire.
6 - Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Turn the supply
and manifold 3/32" hex screw one revolution back
into the gas valve.
7 - Start unit and check for gas leaks. Seal if any found.
Page 33
TABLE 11
Seconds for One Revolution
Natural
2 cu ft 1 cu ft
Dial Dial
160 200
110 136
82 102
66 82
LP
2 cu ft
Dial
400
272
204
164