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WARNING
Do not over torque (800 in-lbs) or under torque (350 in-
lbs) when attaching the gas piping to the gas valve.
Gas supply piping should not allow more than 0.5”W.C.
drop in pressure between gas meter and unit. Supply gas
pipe must not be smaller than unit gas connection.
Compounds used on gas piping threaded joints should be
resistant to action of liqueed petroleum gases.
C-Testing Gas Piping
IMPORTANT
In case emergency shutdown is required, turn o
the main shut-o valve and disconnect the main
power to unit. These controls should be properly
labeled by the installer.
When pressure testing gas lines, the gas valve must be
disconnected and isolated. Gas valves can be damaged if
subjected to more than 0.5 psig (14” W.C.). See Figure 18.
If the pressure is greater than 0.5psig (14”W.C.), use the
manual shut-o valve before pressure testing to isolate
furnace from gas supply.
MANUAL MAIN
VALVE
WILL NOT HOLD
NORMAL TEST
PRESSURE
CAP
ISOLATE
GAS VALVE
1/8 NPT PLUG
FIGURE 19
When checking piping connections for gas leaks, use
preferred means. Kitchen detergents can cause harmful
corrosion on various metals used in gas piping. Use of a
specialty Gas Leak Detector is strongly recommended. It
is available through Lennox under part number 31B2001.
See Corp. 8411-L10, for further details.
Do not use matches, candles, ame or any other
source of ignition to check for gas leaks.
D-Testing Gas Supply Pressure
IMPORTANT
For safety, connect a shut-o valve between the
manometer and the gas tap to permit shut o of gas
pressure to the manometer.
A port on the inlet side of the gas valve provides access to
the supply pressure tap. See Figure 17. Loosen the screw
and connect a manometer to measure supply pressure.
The minimum supply line pressure is 4.5” - 10.5”w.c. For
natural and 11.0 - 13.0” wc for LP/Propane. Tighten after
measurements have been taken.
E- Proper Gas Flow (Approximate)
Furnace should operate at least 5 minutes before check-
ing gas ow. 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 17 below.
NOTE- To obtain accurate reading, shut o all other gas
appliances connected to meter.
TABLE 17
GAS METER CLOCKING CHART
Unit
Seconds for One Revolution
Natural LP/Propane
1 cu ft Dial 2 cu ft Dial 1 cu ft Dial 2 cu ft Dial
-060 60 120 150 300
-080 45 90 112 224
-100 36 72 N/A N/A
Natural - 1000btu/cu ft Propane-2500 btu/cu ft
F-Manifold Pressure, Signal Pressure, Combustion
and High Altitude -01 through -04 Models
IMPORTANT
For safety, connect a shut-o valve between the
manometer and the gas tap to permit shut o of gas
pressure to the manometer.
1 - Turn o the electrical power and gas supply to the
furnace.
2 - Remove the threaded plug from the outlet side of the
gas valve and install a eld-provided barbed tting.
Connect measuring device positive “+” to barbed
tting to measure manifold pressure. See Figure 18
Honeywell gas valve for manifold location.
3 - Install hoses and meter as shown in Figure 21 for
signal pressure measurement.
4 - After allowing unit to stabilize for 8 minutes, record
manifold pressure and compare to value in Table
18 or Table 19. If manifold pressure is within
range, rate check is complete move to step 6. If
manifold pressure is not within range continue.
Valve is not adjustable. Do not adjust manifold
pressure.
5 - Record signal pressure and compare to value in
Table 18 or Table 19. If signal pressure is within
range continue. If the signal is not within range go
to “Troubleshooting”.
6 - Shut o unit and remove manometer and signal
meter after accurate readings has been obtained.
7 - Restart unit and check for gas leaks. Seal any leaks
found.
If the unit has diculty igniting or ignites with loud
resonance the air orice must be checked and re-
placed if necessary.
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