VMP IOM
41
Troubleshooting Gas-Fired Boilers
PROBLEM CAUSE REMEDY
Ignition Failure 1. Power Supply Check fuse or circuit breaker. Reset or replace, as necessary.
2. Ignition Electrodes Check electrodes for carbon buildup and clean if necessary.
Check for proper adjustment. Readjust if necessary.
Check for cracks in porcelain. If found,replace.
3. Transformer Check voltage between transformer leads at terminal block to be sure
transformer is being powered.
4. Flame Safeguard Control Check voltage between ignition terminal and neutral.
Check must be made before control locks out on safety.
If no power, replace control.
5. Faulty Air Switch Check for bad air switch by jumpering the two air switch leads at the
terminal block. If the boiler starts and runs with these terminals
jumpered, the air switch should be replaced.
6. Gas Valve Sticking (Pilot) Check for dirt in valve or orifice and clean if necessary.
Check for faulty actuator or valve and replace if necessary.
7. Gas Supply Check for gas pressure and for intermittent supply problems.
Gas pressure for natural gas should be 3-1/2" W.C. plus fan pressure
at the elbow to the burner and 7" to 11" W.C. at the head of the train.
8. Loose wire connection Check connections to all components.
Flame Failure 1. Power Supply Check fuse or circuit breaker. Reset or replace, as necessary.
2. Gas Supply Check for gas pressure and for intermittent supply problems.
Gas pressure for natural gas should be 3-1/2" W.C. plus fan pressure
at the elbow to the burner and 7" to 11" W.C. at the head of the train.
3. Ignition Electrodes Check electrodes for carbon buildup and clean if necessary.
Check for proper adjustment. Readjust if necessary.
Check for cracks in porcelain; if found, replace.
4. Primary Air Adjustment Check air adjustment.
5. UV Scanner Adjustment Check for dirt on flame scanner and clean.
Check for proper location of detector.
6. Flame Safeguard Control Check voltage at terminal leading to main gas valve. If no power,
replace the control.
7. Loose wire at fuel valve circuit Tighten wiring connections.
8. Contact open on air Adjust to proper setting.
safety switch
9. Scanner wiring reversed Change to correct terminals.
at panel box.
Burner Cut-Off 1. Power Supply Check fuse or circuit; reset or replace, as necessary.
2. Gas Supply Check to be sure main gas cock is not closed.
Check coil in gas valve with OHM meter. Replace if faulty.
Check gas regulator setting and readjust as necessary.
Check inlet gas pressure and increase or decrease as necessary.
3. Ignition Electrodes Check electrodes for carbon buildup and clean if necessary.
Check for proper adjustment Readjust if necessary.
Check for cracks in porcelain; if found replace.
4. Air Switch Check for bad air switch by jumpering the two air switch leads at the
terminal block. If the boiler starts and runs with these terminals
jumpered, the air switch should be replaced.
5. Gas Valve Sticking (Pilot) Check for dirt in valve or orifice and clean if necessary.
Check for faulty actuator or valve and replace if necessary.
6. Weak Amplifier Replace.
7. Weak Pilot Adjust to larger pilot by adjusting pilot gas pressure regulator.
8. Faulty Liquid Level Control Check to see if there is power to terminal number 10 when the sight
glass shows the proper water level. If there is no power at this terminal,
the control is bad and must be replaced.
9. Dirty or defective UV Scanner Clean or replace.
Maintenance
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