www.desatech.com
116647-01B
30
TROUblEShOOTING
WARNING: Turn off heater and let cool before servicing. Only a
qualified service person should service and repair heater.
CAUTION: Never use a wire, needle or similar object to clean
pilot. This can damage pilot unit.
Note:
Before troubleshooting the system, make sure the gas shutoff valve is ON.
The two most common causes of a malfunctioning gas appliance are:
1. Loose wiring connections
2. Construction debris clogging the pilot and/or gas control valve filter
OBSERVED PROBLEM
Ignitor will not spark or pilot
will not light
Pilot will not stay lit
POSSIBLE CAUSE
1. No gas supply or shutoff
valve is OFF
2. Air in gas line
3. Construction debris clogging
pilot orifice
4. Low gas pressure
5. Kinked pilot line
6. Control valve is not opening
7. No power to unit or the
ignition module or power
transformer is bad
8. Vent damper not fully open
1. Loose wiring on ignitor wire
to ignition module and/or
poor ground to ignition mod-
ule
2. Pilot flame too low to sense
REMEDY
1. Check to see if you have gas
supply and that equipment
shutoff valve is opened
2. Repeat lighting procedure sev-
eral times to purge all air out of
lines. If after repeated attempts
appliance does not light, call for
qualified service and repair.
3. Remove debris and dirt, in-
spect and clean any other
possible obstructions
4. Contact your gas supplier to
check pressure
5. Have a qualified technician
replace pilot line
6. Replace control valve (refer to
Replacement Parts
, page 32)
7. Check that main power is on
and that all wire connections
are made correctly to the
ignition model (see
Wiring
Diagram
, page 26). Check for
24 VAC at the secondary side
of the transformer. If 24 VAC
is present and the module does
not operate, have the module
replaced otherwise have the
transformer replaced
8. Open vent damper until fully
locked in OPEN position
1. Check wiring connection.
Refer to wiring diagram (see
Wiring Diagram
, page 26)
and/or check ground wire to
ignition module
2. Clean and adjust pilot burner
and check gas supply and inlet
pressure to unit
Note:
Have a qualified technician
replace pilot assembly if broken
or corroded
