Maxi Comet Executive Exec-66-G - Burner Ignition; Burner Starts Normally, then Shuts down; Flame Does Not Travel down the Entire Length of the Burner; Gas Flow: Poor, Irregular, None

Comet Executive Gas Troubleshooting
6-13
WARNING
Only trained personnel with experience
in gas, electrical or mechanical repair
should troubleshoot and repair the unit.
Troubleshooting
WARNING
Read the REPAIR chapter and make
sure that the power is disconnected
before doing any repairs.
BURNER IGNITION
ISSUE POSSIBLE CAUSE SOLUTION
Flame Does Not Travel Down
the Entire Length of the
Burner
1. External and/or internal
manual gas valves are
closed or partially closed.
• Open the manual gas valves.
2. Gas pressure is wrong. • Refer to the Gas Flow: Poor, Irregular,
None issue below.
3. Burner tips are clogged.
• Clean. Refer to Burner Tip Mainte-
nance on page 7-32.
Gas Flow: Poor, Irregular,
None
1. External and/or internal
manual gas valves are
closed.
• Make sure the external and internal
manual gas valves are open before
starting the burner.
2. Incoming gas pressure is
too high or too low due to
an incorrect gas supply or
other gas-burning equip-
ment in the area.
• Check the incoming gas pressure during
periods of peak demand and adjust, if
necessary. Refer to Gas Connection
Checkout on page 2-20.
3. Gas valve coil or ignition
control is bad.
• Check the voltage at the gas valve coil
when the burner system calls for heat.
- If 24 VAC is present but the valve
doesn’t open, the gas valve is bad and
must be replaced.
- If the voltage is well below 24 VAC,
check the line voltage to the unit.
- If there is no voltage at all, the ignition
control may need to be replaced.
4. On-site gas demand is
irregular due to other equip-
ment.
• Check the incoming gas pressure during
periods of peak demand and adjust, if
necessary. Refer to Gas Connection
Checkout on page 2-20.
Burner Starts Normally, Then
Shuts Down
1. Gas flow to the burner is
insu󰀩cient.
• Refer to the Gas Flow: Poor, Irregular,
None issue above.
2. Exhaust system backflow
has caused sail switch to
close.
• Check/clean exhaust system as neces-
sary. For cleaning instructions, refer
to Check and Clean Sail Switch and
Exhaust Blower Wheel on page 4-11.
• Check/replace defective sail switch.
3. If no other problems are
found and the burner will
not stay lit, the ignition
control is bad.
• Check. Replace, if necessary.
TOC
INDEX