beautypg.com

Maxim – PVI Industries MAXIM INTEGRATED WATER HEATING SYSTEM User Manual

Page 11

background image

PV500-17 05-2000

Section 17

11

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. See Section 15, page 11.

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.