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NB18/NB24 Gas Log Set
Monessen • NB18/24 Gas Log Set Installation/Owner's Manual • 81D0107 • Rev E • 04/18
TROUBLESHOOTING
MILLIVOLT CONTROL SYSTEM
NOTE: All troubleshooting items are listed in order of operation.
Turn appliance OFF and allow to cool before servicing. Only a qualified service person should service and
repair the heater.
WARNING
PROBLEM
POSSIBLE CAUSE
SOLUTION
When ignitor button is pressed, there is
no spark at ODS/pilot.
Ignitor electrode positioned wrong.
Replace ignitor.
Ignitor electrode is broken.
Replace ignitor.
Ignitor electrode not connected to ignitor
cable.
Reconnect ignitor cable.
Ignitor cable pinched or wet. Keep ignitor
cable dry.
Free ignitor cable if pinched by any metal
or tubing.
Broken ignitor cable.
Replace ignitor cable.
Bad piezo ignitor.
Replace piezo ignitor.
Appliance produces unwanted odors.
Appliance burning vapors from paint, hair
spray, glues, etc.
Ventilate room. Stop using odor causing
products while heater is running.
Gas leak.
Locate and correct all leaks.
Initial burn off.
Ventilate room and turn unit on high until
odor is gone. Odor should be gone after
six hours of continuous use.
Appliance shuts off during use.
Not enough fresh air is available for
ODS/pilot to operate.
Open window and/or door for ventilation.
Low line pressure.
Contact local gas company.
ODS/pilot is partially clogged.
Clean ODS/pilot.
Defective thermopile.
Check wire connections. Check output
should be 500 millivolts across TH/TP
and TP Terminals with ON/OFF switches
off.
Restrictions in incoming air flow.
Check for bottom riser on glass door,
sunken fireplace, excessive lava rock/
cinders densely packed against grate.
Gas odor even when control knob is in
OFF position.
Gas leak.
Locate and correct all leaks.
Control valve defective.
Replace control valve.
When ignitor button is pressed, there is
spark at ODS pilot, but no ignition.
Gas supply turned off or manual shutoff
valve closed.
Turn on gas supply or open manual
shutoff valve.
Control knob not in PILOT position.
Turn control knot to PILOT position.
Control knob not pressed in while in
PILOT position.
Press in control knob while in PILOT
position.
Air in gas lines when installed.
Continue holding down control knob.
Repeat igniting operation until air is
removed.
ODS/pilot is clogged.
Replace ODS/pilot assembly or get it
serviced.
Gas regulator setting is not correct.
Check incoming pressure. Replace gas
regulator.
Summary of Contents for BC18-R
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