Troubleshooting guide

PV500-17 07/13 Section 17
13
MAXIM
TROUBLESHOOTING SUGGESTIONS
AXIAL FLOW GAS BURNER
1. BURNER FAILS TO START
Defective On/Off switch. Replace switch.
A. Control circuit has an open control contact.
Check limits, low water cutoff, proof of closure
switch and others as applicable.
B. Bad fuse or switch open on incoming power
source. Correct as required.
C. Flame safeguard control safety switch
tripped out. Reset and determine cause for
apparent flame failure.
D. Loose connections or faulty wiring. Tighten all
terminals screws and consult wiring diagram
furnished with the burner.
E. 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.
F. Defective blower motor. Check for free rotation
of fan wheel. Repair or replace.
G. Air proving switch is not properly adjusted.
Adjust per instructions; page 11 of this manual.
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 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 as 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.