14
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 |
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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. |
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| B. Defective or misaligned electrode | Using a match, light pilot. If pilot lights, turn off pilot and | |
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| at pilot (spark at electrode). | trigger the ignitor button again. If pilot lights, an improper |
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| gas mixture caused the bad lighting and a longer purge |
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| period is recommended. If pilot will not light – check gap at |
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| electrode and pilot - should be ³⁄₈" to have a strong spark. If |
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| gap measures ³⁄₈", replace pilot (Figure 9 on page 7). |
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| C. Gas supply pressure errant. | Check inlet gas pressure. It should be within the limits as |
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| marked on the rating plate. |
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| D. Pilot orifice plugged. | Clean or replace pilot orifice. |
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2. | Pilot will not stay lit after | A. Defective pilot generator | Check pilot flame, it must impinge on thermogenerator |
| carefully following the | (thermogenerator). | (Figure 9 on page 7). Clean and/or adjust pilot for maxi- |
| lighting instructions. |
| mum flame impingement on thermogenerator. Ensure that |
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| the connection between the valve and thermogenerator are |
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| tight and secure. |
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3. | Pilot burning, no gas to | A. Damper closed or Damper Switch | Ensure damper control lever is locked in the open position, |
| burner, Valve knob “ON,” | defective. | all the way to the right. If the damper control lever is locked |
| Wall Switch “ON.” |
| in the open position troubleshoot through Steps B., C. and |
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| D. below. If the main burner will still not light, determine if |
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| the damper switch is defective and replace if necessary. |
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| B. Wall switch or wires defective. | Check wall switch and wires for proper connections. Jumper |
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| wire across terminals at wall switch, if burner comes on, |
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| replace defective wall switch. If okay, jumper wires across |
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| wall switch wires at valve, if burner comes on, wires are |
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| faulty or connections are bad. |
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| C. Thermopile may not be generating | Check thermopile with millivolt meter. Take reading at ther- |
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| sufficient millivoltage. | mopile terminals of gas valve. Should read 325 millivolts |
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| minimum with optional wall switch “OFF.” Replace faulty |
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| thermopile if reading is below specified minimum. |
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| D. Plugged burner orifice. | Check burner orifice for stoppage and remove. |
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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 9 on page 7). |
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| valve safety to drop out. |
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