PV500-9 04-2000
(9)
Section 9
TROUBLESHOOTING SUGGESTIONS
GAS BURNER
1. BURNERS FAILS TO START
A.
Defective On/Off or fuel transfer switch. Replace switch.
B. Control circuit has an open control contact. Check limits, low water cutoff, proof of closure switch and
others as applicable.
C. Bad fuse or switch open on incoming power source. Correct as required.
D. Motor overloads tripped. Reset and correct cause for trip out.
E.
Flame safeguard control safety switch tripped out. Reset and determine cause for apparent flame
failure.
F.
Loose connections or faulty wiring. Tighten all terminal screws and consult wiring diagram furnished
with the burner.
G. Flame safeguard control starting circuit blocked due to flame relay being energized. Possible defective
scanner or flame rod – replace. Possible defective amplifier – replace. Scanner actually sighting flame
due to leaking fuel valve – correct unwanted flame cause. Defective flame safeguard control – replace.
H. Defective blower motor. Repair or replace.
2. OCCASIONAL LOCKOUTS FOR NO APPARENT REASON
A.
Gas pilot ignition failure. Check to see that ignition is instant and that flame signal readings are stable
and above minimum values. Use a manometer or 0 to 10" W.C. gas pressure gauge to make certain that
pressure is as recommended.
B. Loose or broken wires. Check all wire nut connections and tighten all terminal screw connections in
panel and elsewhere as appropriate.
C. With flame safeguard controls that incorporate the air flow switch in the non-recycling circuit, ensure
that when main flame lights, the air flow switch is not so critically set as to allow occasional momentary
opening of the air switch contacts.
D. Occasional low voltage supply. Have local utility correct. Make certain that the burner control circuit
transformer (if supplied) is correct for the voltage and power (VAC) being supplied.
E.
Occasional low gas supply pressure. Have local utility correct.
3. BURNER MOTOR RUNS, BUT PILOT DOES NOT LIGHT
A.
Gas supply to burner shut off – make sure all manual gas supply valves are open. Automatic high
pressure valve at meter such as "Sentry" type tripped shut due to high gas pressure – reset valve and
correct cause for trip out.
B. Pilot solenoid valve not opening – listen and feel for valve actuation. Solenoid valve not being powered
– check electrical circuitry. Replace coil or entire valve if coil is burned out.
C. Defective gas pilot regulator – replace.
D. Gas pressure too high or too low at pilot orifice (if supplied). Check orifice size in gas pilot assembly.
Replace if incorrect. Readjust pressure as required.
E.
Defective ignition transformer – replace. Incorrect ignition electrode settings – readjust as required.
F.
Defective flame safeguard control or plug in purge timing card. Replace as required.
G. Air flow switch not making circuit – check out electrically. Defective air flow switch – replace. Air switch
negative pressure sensing tube out of position – reposition if necessary.
4. BURNER MOTOR RUNS & PILOT LIGHTS, BUT MAIN GAS FLAME IS NOT ESTABLISHED
A.
Main shut off or test cock closed. Check to make certain fully open.
B. Pilot flame signal reading too low to pull in flame safeguard relay. Readjust as required.
C. Defective automatic main or auxiliary gas shut off valves. Check electrical circuitry to valves. Replace
valves or correct circuitry as required.
D. Main diaphragm shut off valve opening too slowly. Adjust bleed on valve.
E.
Defective flame safeguard control or plug in amplifier. Check and replace as required.
F.
Butterfly valve set incorrectly on modulating burner. Readjust as required.
G. Main gas pressure regulator atmospheric vent line obstructed. Correct.
H. Defective main gas pressure regulator – replace. Misadjusted main gas pressure regulator – readjust to
meet required operational values.
