Model G3B Gas burner — Instruction manual
MNG3B Gas 041015
12
4. Check System • Start-up Burner/Appliance
Inspect/check system
Before starting the burner and appliance, verify the system has been installed
as directed by this manual and the appliance instructions.
Check gas piping for leaks
Disconnect the burner from the gas supply line if gas line
test pressure will exceed 14 inches w.c. Exposing the burner
combination gas valve to pressure higher than 14 inches w.c.
can damage the valve seat, resulting in potentially unsafe
operation.
You can usually test the gas piping by allowing the line to fill with gas to
main regulator outlet pressure.
1. Shut off gas flow to all appliances connected to the meter.
2. If test pressure will be less than 14 inches w.c., turn the burner combi-
nation gas valve knob to OFF.
If test pressure will be higher than 14
inches, disconnect the burner from the gas line
by shutting off the
main manual gas valve installed near the burner (per Figure 5, page 9)
and disconnecting the ground joint union. See warning above.
3. Watch the gas meter dial. For a one half cubic foot per revolution dial,
there should be no movement of the dial for at least 5 minutes. For
larger volumes per revolution, increase this time proportionately.
4. If you detect a gas leak, locate the leak with a soap suds mixture and
repair it. Then test the system for leaks again.
Do not test for leaks with an open flame. And do not use
oxygen as a test gas. Either of these could cause an
explosion, resulting in severe personal injury, death or
substantial property damage.
Bleed gas line
Purge all air from the gas line. Purge to outside of the building, NEVER into
the appliance or burner.
Leak test near-burner gas piping
If piping near burner has not already been pressure tested, open main
manual gas valve on supply to burner and smell around area for any signs of
gas. Apply a soap suds mixture to all gas piping joints near burner and check
for any leaks. If any leaks appear, repair before proceeding and retest.
Set air throttle
1. See Figure 8. Loosen air throttle locking nut.
2. Rotate the air throttle plate clockwise to the closed position.
3. Check the air throttle indicator. The “0” position of the indicator should
be even with the end of the air inlet tube. If not, bend the arm slightly
until the indicator reads zero.
4. Rotate air throttle until indicator points to setting given in Figure 4,
page 8.
5. Tighten air throttle locking nut.
Figure 8
Air throttle adjustment
Do not start the burner if you smell gas or if there may be gas
present in the appliance combustion chamber, heat exchanger
or the vent system. An explosion could occur, causing severe
personal injury, death or substantial property damage.
During initial start-up, you must be constantly alert for
emergency conditions such as fuel leaks, electrical malfunc-
tions, etc. Familiarize yourself with the location of manual
shutoff valves and switches so you can quickly use them if
needed.
If the burner fails to ignite, NEVER attempt to manually bypass
the normal sequence of the control, which provides purging
of the combustion chamber.
6. The Figure 4 setting will probably be satisfactory without change. If the
combustion test indicates a need for more or less air, however, you will
have to adjust the throttle accordingly.
Check burner and Honeywell S89C control
Inspect burner thoroughly. Verify all components are secure and burner
is in good condition. Verify all wiring is in place and all components are
secure and in position.
Verify flame failure lockout of Honeywell control
1. Install a hose barb fitting in the combination gas valve outlet pressure tap
and connect with a hose to a U-tube manometer.
2. Close the main manual gas valve and turn the combination gas valve knob
to ON.
3. Turn on power to appliance and set appliance limit(s) to call for heat.
4. Burner motor will start. The Honeywell S89C control will run the blower for
34 seconds (pre-purge and ignitor warm-up). Then the combination gas
valve will open and the “Valve on” light will light. (The manometer should
show almost no pressure, because the main manual gas valve is closed.)
5. After 6 seconds, the S89C will lockout. The ignitor will shut off and the gas
valve will close. Turn off power or interrupt thermostat circuit for 45 seconds.
The control should reset. Turn off power and set controls to stop call for
heat.
6. If lockout does not occur, replace the S89C control.