20

TROUBLESHOOTING

TROUBLESHOOTING

Note: For additional help, visit DESA’s technical service web site at www.desatech.com.

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

POSSIBLE CAUSE

REMEDY

Ignitor will not spark or pilot will not light

1.

No gas supply, or shutoff valve is OFF

1.

Check to see if you have gas supply and

 

 

 

 

that equipment shutoff valve is opened

 

2.

Air in gas line

2.

Repeat lighting procedure several times

 

 

 

 

to purge all air out of lines. If after re-

 

 

 

 

peated attempts appliance does not light,

 

 

 

 

call for qualified service and repair.

 

3.

Construction debris clogging pilot orifice

3.

Remove debris and dirt, inspect and

 

 

 

 

clean any other possible obstructions

 

4.

Low gas pressure

4.

Contact your gas supplier to check

 

 

 

 

pressure

 

5.

Kinked pilot line

5.

Have a qualified technician replace pi-

 

 

 

 

lot line

 

6.

Control valve knob is not opening

6.

Replace control valve (Refer to Replace-

 

 

 

 

ment Parts, page 19)

 

7.

No power to unit or the ignition module

7.

Check that main power is on and that all

 

 

or power transformer is bad

 

wire connections are made correctly to

 

 

 

 

the ignition model (see Wiring Diagram,

 

 

 

 

page 19). Check for 24 VAC at the sec-

 

 

 

 

ondary side of the transformer. If 24

 

 

 

 

VAC is present, and the module does not

 

 

 

 

oporate, have the module replaced oth-

 

 

 

 

erwise have the transformer replaced.

 

8.

Vent damper not fully open

8.

Open vent damper until fully locked in

 

 

 

 

OPEN position

 

 

 

 

 

Pilot will not stay lit

1.

Loose wiring on ignitor wire to ignition

1.

Check wiring connection. Refer to wir-

 

 

module and/or poor ground to ignition

 

ing diagram (see Wiring Diagram, page

 

 

module

 

19) and/or check ground wire to igni-

 

 

 

 

tion module

 

2.

Pilot flame too low to sense

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

 

 

 

 

 

No gas to burner, although wall switch and

1.

Wall switch wires defective or too long

1.

Check electrical connections

valve are set to the ON position

2.

Thermopile not generating sufficient

2.

Recheck problems 1 and 2

 

 

voltage

 

 

 

 

 

 

 

Frequent pilot outage

1.

Pilot flame may be too low, causing

1.

Clean and adjust pilot flame for maximum

 

 

safety pilot to “drop out”

 

flame impingement on thermopile

 

2.

Improper venting or excessive blockage

2.

Have the vent system inspected, includ-

 

 

 

 

ing the termination cap. Remove any

 

 

 

 

restriction or obstruction

For more

 

visit www.

 

.com

108796-01E

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Desa VM36E(B, VM42E(B installation manual Troubleshooting, Observed Problem Possible Cause Remedy