Troubleshooting; Millivolt Control System - Monessen Hearth NB24 Installation And Operating Instructions Manual

TROUBLESHOOTING

WARNING
Turn appliance OFF and allow to cool before servicing. Only a qualified service person should service and
repair the heater.

MILLIVOLT CONTROL SYSTEM

NOTE: All troubleshooting items are listed in order of operation.
PROBLEM
When ignitor button is pressed, there is
no spark at ODS/pilot.
Appliance produces unwanted odors.
Appliance shuts off during use.
Gas odor even when control knob is in
OFF position.
When ignitor button is pressed, there is
spark at ODS pilot, but no ignition.
Monessen • NB18/24 Gas Log Set Installation/Owner's Manual • 81D0107 • Rev E • 04/18
42
POSSIBLE CAUSE
Ignitor electrode positioned wrong.
Ignitor electrode is broken.
Ignitor electrode not connected to ignitor
cable.
Ignitor cable pinched or wet. Keep ignitor
cable dry.
Broken ignitor cable.
Bad piezo ignitor.
Appliance burning vapors from paint, hair
spray, glues, etc.
Gas leak.
Initial burn off.
Not enough fresh air is available for
ODS/pilot to operate.
Low line pressure.
ODS/pilot is partially clogged.
Defective thermopile.
Restrictions in incoming air flow.
Gas leak.
Control valve defective.
Gas supply turned off or manual shutoff
valve closed.
Control knob not in PILOT position.
Control knob not pressed in while in
PILOT position.
Air in gas lines when installed.
ODS/pilot is clogged.
Gas regulator setting is not correct.
NB18/NB24 Gas Log Set
SOLUTION
Replace ignitor.
Replace ignitor.
Reconnect ignitor cable.
Free ignitor cable if pinched by any metal
or tubing.
Replace ignitor cable.
Replace piezo ignitor.
Ventilate room. Stop using odor causing
products while heater is running.
Locate and correct all leaks.
Ventilate room and turn unit on high until
odor is gone. Odor should be gone after
six hours of continuous use.
Open window and/or door for ventilation.
Contact local gas company.
Clean ODS/pilot.
Check wire connections. Check output
should be 500 millivolts across TH/TP
and TP Terminals with ON/OFF switches
off.
Check for bottom riser on glass door,
sunken fireplace, excessive lava rock/
cinders densely packed against grate.
Locate and correct all leaks.
Replace control valve.
Turn on gas supply or open manual
shutoff valve.
Turn control knot to PILOT position.
Press in control knob while in PILOT
position.
Continue holding down control knob.
Repeat igniting operation until air is
removed.
Replace ODS/pilot assembly or get it
serviced.
Check incoming pressure. Replace gas
regulator.