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POWER
VT@WATER
HEATER
TROUBLESHOOTING SUGGESTIONS
GAS BURNER
1. BURNER FAILS TO START:
a) Defective on/off switch. Replace switch.
b) Control circuit has open control c:lntact.
Check limits, low water cutoff, and 01l.ers as
applicable.
c) Bad fuse or switch opens on incoming' power
source. Correct as required.
d) Flame safeguard control safety switch tripped
out.
Reset and determine
cause
of
apparent
flame failure.
e) Loose connections or faulty wiring. Tighten all
terminal screws and consult wiring diagram
furnished with the heater.
f)
Flame
safeguard
control
starting .-circuit
blocked due to flame relay being enwglzed.
Possible defective scanner or flame rod - t-aplace.
Possible defective amplifier - replace.
~';~nner
actually sighting flame due to leaking fuel valve -
correct unwanted flame cause. Defective flame
safeguard control - replace.
g) Defective blower motor. Check for free
I
atation
of fan wheel. Repair or replace.
h) Air proving switch is not properly adjusted.
Adjust per instructions; page 12, paragraph 9.
i)
Defective circulation pump. Repair or replace.
j)
Circulation flow switch not properly adllJsted.
Adjust flow switch counter-clockwise until airflow
light comes on.
2. OCCASIONAL LOCKOUTS FOR NO APPARENT
REASON:
a) Gas pilot ignition failure. Check to see that
ignition is instant and flame signal readings are
stable and above minimum values. Use an incline
manometer to make certain pressure is as
recommended.
b) Loose or broken wires. Check all wi,.e
nut
connections
and tighten
all
terminal
screw
connections
in
panel
and
elsewher-3
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 supply voltage. Contact local
utility to correct. Make certain the burner control
circuit transformer (if supplied) is of the correct
voltage and power (AC) being supplied.
e) Occasional low gas supply pressure. Contact
local utility to correct.
f)
Excessive
flue
gas
recirculation,
causing
unreliable or unstable operation. Reduce the
orifice size in the FGR union and readjust the gas
regulators to achieve proper excess air in
combustion.
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 of 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) Airflow switch not making circuit. Check out
electrically. Defective air flow switch. Replace.
Air switch negative pressure sensing tube out
of position. Reposition as necessary.
PV500-19 04·2005
19
Section 19
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