www.desatech.com
116237-01H
31
VENTING SYSTEM
Conduct annual inspection of the venting
system following these guidelines:
1. Check areas of venting system that are
exposed to the weather for corrosion (rust
spots or streaks and, in extreme cases,
holes). Have these items replaced im-
mediately by a qualified service person.
2. Remove the vent cap and shine a flashlight
into the vent. Remove any foreign material.
CLEANING AND MAINTENANCE
Continued
3. Check for evidence of excessive condensa-
tion. Continuous condensation can cause
corrosion of caps, pipes and fittings and can
be caused by having excessive lateral runs,
too many elbows or exterior portions of the
system being exposed to cold weather.
4. Inspect joints to verify that no pipe section
or fitting has been disturbed and loos-
ened. Check mechanical supports such
as wall straps for rigidity.
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: All troubleshooting items are listed in order of operation.
pOSSIBLE CAUSE
1. No gas supply or shutoff
valve is OFF
2. Air in gas line
3. Construction debris clog-
ging pilot orifice
4. Low gas pressure
5. Kinked pilot line
6. Control valve is not opening
7. No power to unit or ignition
module or power trans-
former is bad
REMEDY
1. Check to see if you have gas
supply and that equipment
shutoff valve is opened
2. Repeat lighting procedure
several 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,
inspect 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 34)
7. Check that main power is on
and that all wire connections
are made correctly to ignition
model (see
Wiring Diagram
,
page 27). Check for 24 VAC
at secondary side of trans-
former. If 24 VAC is present
and module does not oper-
ate, have module replaced
otherwise have transformer
replaced
OBSERVED PROBLEM
Ignitor will not spark or pilot
will not light
