Monessen Hearth NBST27NV-B Installation & Owner's Manual page 36

Troubleshooting
PROBLEM
ODS/pilot lights, but flame goes out when
control knob is released.
Burner does not light after ODS/pilot is lit.
Burner backfires during combustion.
Slight smoke or odor during initial opera-
tion.
Logs appear to smoke after initial opera-
tion.
Heater produces a whistling noise when
burner is lit.
No gas to pilot.
WARNING
If the gas quality is bad, your pilot may not stay lit, the burners may produce soot and the heater may
backfire when lit. If the gas quality or pressure is low, contact your local gas supplier immediately.
36 Monessen • NBST27-B Gas Log Set Owner's /Installation Manual • 4615-900 Rev. D • 01/2020
POSSIBLE CAUSE
Control knob not fully pressed in.
Control knob not pressed in long enough.
Manual shutoff valve not fully open.
Thermocouple connection loose at con-
trol valve.
Pilot flame not touching thermocouple,
which allows thermocouple to cool, caus-
ing pilot flame to go out. This problem
could be caused by either low gas pres-
sure, or a dirty or partially clogged ODS/
pilot.
Thermocouple damaged.
Control valve damaged.
Burner orifice is clogged.
Burner orifice diameter is too small.
Inlet gas pressure is too low.
Manifold Pressure is too low.
Burner orifice is clogged.
Burner orifice is clogged or damaged.
Burner is damaged.
Gas regulator is defective.
Vapors from paint or curing process of
logs.
Turning control knob to HIGH position
when burner is cold.
Air in gas line.
Dirty or partially clogged burner orifices.
LP regulator shut down due to inlet pres-
sure too high.
SOLUTION
Press in control knob fully.
After ODS/pilot lights, keep control knob
pressed in for 30 seconds.
Fully open manual shutoff valve.
Hand tighten thermocouple connection
until snug, then tighten ⁄ turn more.
1
4
Contact local gas company.
Replace thermocouple.
Replace control valve.
Clean burner or replace burner orifice
Replace orifice.
Contact local gas company.
Contact local gas company.
Clean burner or replace burner orifice.
Clean burner or replace burner orifice.
Replace burner.
Replace gas regulator.
1. Problem will stop after a few hours
of operation. Run the heater with the
damper open if you have one, or open a
window for the first few hours.
OR
2. Log heater is intended to be smoke-
less. Turn OFF heater and call qualified
service person.
Turn control knob to LOW position and
let warm up for a minute.
Operate burner until air is removed from
line. Have gas line checked by local gas
company.
Clean burner or replace burner orifice.
1. Verify LP tank regulator is installed and
set at 11" to 13" w.c.
OR
2. Replace regulator on heater.