TROUBLESHOOTING THE MILLIVOLT GAS CONTROL SYSTEM

Note: Before troubleshooting the gas control system, be sure external gas shut off valve (located at gas supply inlet) is in the “ON” position.

Important: Valve system troubleshooting should only be accomplished by a qualified service technician.

 

SYMPTOM

POSSIBLE CAUSES

CORRECTIVE ACTION

 

 

 

 

 

1.

Spark ignitor will not light

A. Defective ignitor

Check for spark at electrode and pilot; if no spark and

 

pilot after repeated

(no spark at electrode).

electrode wire is properly connected, replace ignitor.

 

triggering of ignitor button.

 

 

 

B. Defective or misaligned electrode

Using a match, light pilot. If pilot lights, turn off pilot and

 

 

 

 

 

 

at pilot (spark at electrode).

trigger the ignitor button again. If pilot lights, an improper

 

 

 

 

gas mixture caused the bad lighting and a longer purge

 

 

 

 

period is recommended. If pilot will not light – check gap at

 

 

 

 

electrode and pilot - should be ¹⁄₈" to have a strong spark. If

 

 

 

 

gap measures ¹⁄₈", replace pilot (Figure 8 on page 6 ).

 

 

 

 

 

 

 

 

C. Gas supply pressure errant.

Check inlet gas pressure. It should be within the limits as

 

 

 

 

marked on the rating plate.

 

 

 

 

 

 

 

 

D. Pilot orifice plugged.

Clean or replace pilot orifice.

 

 

 

 

 

2.

Pilot will not stay lit after

A. Defective pilot generator

Check pilot flame, it must impinge on thermogenerator

 

carefully following the

(thermogenerator).

(Figure 8 on page 6 ). Clean and/or adjust pilot for maxi-

 

lighting instructions.

 

mum flame impingement on thermogenerator. Ensure that

 

 

 

 

the connection between the valve and thermogenerator are

 

 

 

 

tight and secure.

 

 

 

 

 

3.

Pilot burning, no gas to

A. Wall switch or wires defective.

Check wall switch and wires for proper connections. Jumper

 

burner, Valve knob “ON,”

 

wire across terminals at wall switch, if burner comes on,

 

Wall Switch “ON.”

 

replace defective wall switch. If okay, jumper wires across

 

 

 

 

wall switch wires at valve, if burner comes on, wires are

 

 

 

 

faulty or connections are bad.

 

 

 

 

 

 

 

 

B. Thermopile may not be generating

Check thermopile with millivolt meter. Take reading at ther-

 

 

 

sufficient millivoltage.

mopile terminals of gas valve. Should read 325 millivolts

 

 

 

 

minimum with optional wall switch “OFF.” Replace faulty

 

 

 

 

thermopile if reading is below specified minimum.

 

 

 

 

 

 

 

 

C. Plugged burner orifice.

Check burner orifice for stoppage and remove.

 

 

 

 

4.

Frequent pilot/burner outage

A. Pilot flame may be too low or

Clean and/or adjust pilot flame for maximum flame impinge-

 

problem.

blowing (high) causing the pilot/

ment on thermogenerator (Figure 8 on page 6 ).

 

 

 

valve safety to drop out.

 

 

 

 

 

 

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