Vermont Castings NBST27 Installation Instructions Manual page 24

NBST27 Unvented Gas Log Set
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 dur-
ing initial operation.
Logs appear to smoke
after initial operation.
Heater produces a whis-
tling noise when burner is
lit.
No gas to pilot.
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.
24
Possible Cause
1. Control knob not fully pressed in.
2. Control knob not pressed in long
enough.
3. Manual shutoff valve not fully open.
4. Thermocouple connection loose at
control valve.
5. Pilot flame not touching thermocou-
ple, which allows thermocouple to
cool, causing pilot flame to go out.
This problem could be caused by
either low gas pressure, or a dirty or
partially clogged ODS/pilot.
6. Thermocouple damaged.
7. Control valve damaged.
1. Burner orifice is clogged.
2. Burner orifice diameter is too small.
3. Inlet gas pressure is too low.
1. Manifold Pressure is too low.
2. Burner orifice is clogged.
1. Burner orifice is clogged or dam-
aged.
2. Burner is damaged.
3. Gas regulator is defective.
1. Vapors from paint or curing process
of logs.
1. Turning control knob to HIGH posi-
tion when burner is cold.
2. Air in gas line.
3. Dirty or partially clogged burner
orifices.
1. LP regulator shut down due to inlet
pressure too high.
TROUBLESHOOTING
Solution
1. Press in control knob fully.
2. After ODS/pilot lights, keep control
knob pressed in for 30 seconds.
3. Fully open manual shutoff valve.
4. Hand tighten thermocouple connection
until snug, then tighten 1/4 turn more.
5. Contact local gas company.
6. Replace thermocouple.
7. Replace control valve.
1. Clean burner or replace burner orifice.
2.
3.
1. Contact local gas company.
2. Clean burner or replace burner orifice.
1. Clean burner or replace burner orifice.
2. Replace burner.
3. 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.
2. Log heater is intended to be smoke-
less. Turn OFF heater and call qualified
service person.
1. Turn control knob to LOW position and
let warm up for a minute.
2. Operate burner until air is removed
from line. Have gas line checked by lo-
cal gas company.
3. Clean burner or replace burner orifice.
1. Verify LP tank regulator is installed and
set at 11" to 13" w.c.
2. Replace regulator on heater.
81D3032