Desa WMN20A - Manual (Page 20)

www.desatech.com 124002-01C 20
OBSERvED PROBLEM
ODS/pilot lights but flame
goes out when control knob
is released
Burner does not light after
ODS/pilot is lit
Delayed ignition of burner
Burner backfiring during com-
bustion
REMEDY
1. Press in control knob fully
2. After ODS/pilot lights, keep
control knob pressed in 30
seconds
3. Fully open equipment shut-
off valve
4. Hand tighten until snug,
then tighten 1/4 turn more
5. A) Contact local natural or
propane/LP gas company
B) Clean ODS/pilot (see
Cleaning and Maintenance,
page 18) or replace ODS/
pilot assembly
6. Replace pilot assembly
7. Replace control valve
1. Clean burner (see Cleaning
and Maintenance, page 18)
or replace burner orifice
2. Contact local natural or
propane/LP gas company
1. Contact local natural or
propane/LP gas company
2. Clean burner (see Cleaning
and Maintenance, page 18)
or replace burner orifice
1. Clean burner (see Cleaning
and Maintenance, page 18)
or replace burner orifice
2. Replace burner
3. Replace gas regulator
POSSIBLE CAUSE
1. Control knob not fully
pressed in
2. Control knob not pressed in
long enough
3. Equipment shutoff valve not
fully open
4. Thermocouple connection
loose at control valve
5. Pilot flame not touching
thermocouple, which al-
lows thermocouple to cool,
causing pilot flame to go
out. This problem could be
caused by one or both of
the following:
A) Low gas pressure
B) Dirty or partially clogged
ODS/pilot
6. Thermocouple damaged
7. Control valve damaged
1. Burner orifice is clogged
2. Inlet gas pressure is too
low
1. Manifold pressure is too
low
2. Burner orifice is clogged
1. Burner orifice is clogged or
damaged
2. Burner damaged
3. Gas regulator defective
TRoUBlesHooTING
Continued