Heating System Service Checks; Csa Certification; Testing Gas Supply Pressur; Check Manifold Pressure - Lennox EL296UH045XE36B Unit Information

IV-HEATING SYSTEM SERVICE CHECKS
A-CSA Certification
All units are CSA design certified without modifications.
Refer to the EL296UHE Installation Instruction.
B-Gas Piping
CAUTION
If a flexible gas connector is required or allowed by
the authority that has jurisdiction, black iron pipe
shall be installed at the gas valve and extend outside
the furnace cabinet.
WARNING
Do not exceed 600 in-lbs (50 ft-lbs) torque 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 liquefied petroleum gases.
C-Testing Gas Piping
IMPORTANT
In case emergency shutdown is required, turn off
the main shut‐off 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 dis­
connected and isolated. Gas valves can be damaged if
subjected to more than 0.5 psig (14" W.C.). See figure 51. If
the pressure is greater than 0.5psig (14"W.C.), use the
manual shut-off valve before pressure testing to isolate fur­
nace from gas supply.
GAS PIPING TEST PROCEDURE
MANUAL MAIN SHUT-OFF VALVE
WILL NOT HOLD TEST PRESSURE
IN EXCESS OF 0.5 PSIG (14"W.C.)
GAS VALVE
FIGURE 51
1/8 NPT PLUG
CAP
Page 45
When checking piping connections for gas leaks, use pre­
ferred means. Kitchen detergents can cause harmful cor­
rosion on various metals used in gas piping. Use of a spe­
cialty 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, flame or any other
source of ignition to check for gas leaks.
D-Testing Gas Supply Pressure
An inlet post located on the gas valve provides access to
the supply pressure. See figure 50. 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 23
for supply line pressure.
E-Check Manifold Pressure
A manifold pressure post located on the gas valve provides
access to the manifold pressure. See figure 50. Back out
the 3/32 hex screw one turn. Follow the steps below and
use figure 52 as a reference. Gas manifold Kit 10L34 pro­
vides additional components if needed
1 - Connect the 5/16" round tubing to the manifold post.
Secure with the clamp.
2 - Connect the reducer fitting to the 5/16" round tubing
followed by a piece of 10" length square tubing.
3 - Connect the other end of the square tubing to the "+"
positive side of the measuring device.
4 - Take the 2" length square tubing, tee, 10" length of
square tubing and tee into the gas valve regulator vent
hose. Connect to the measuring device negative "-"
side.
5 - Ignite unit on low fire and let run for 5 minutes to allow
for steady state conditions.
6 - After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in table
23.
7 - If necessary, make adjustments. Figure 50 shows
location of high fire and low fire adjustment screws.
6 - Repeat steps 5, 6 and 7 on high fire. See values in
table 23.
IMPORTANT
For safety, connect a shut‐off valve between the ma­
nometer and the gas tap to permit shut off of gas
pressure to the manometer.
NOTE - Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Re-start unit and
check gas valve for gas leaks.