28
FAULTS
Pilot fails to light, no discharge spark
noted on electrode.
Pilot burner goes out when ignition
button is released.
Main burner does not start either to
draw off D.H.W. or for heating.
Boiler turns on, but after 10 seconds
“locks out” (“IONO” version).
Gas valve fails to modulate in D.H.W. phase.
Gas valve works only at minimum
heat output in heating phase.
Main burner fails to start in
D.H.W. generation phase.
LIKELY CAUSES AND SOLUTIONS
– Check that gas inflow is regular and that all air has
been purged from pipes.
– Check the 1.6 Amp fuse is sound.
– Check the micro PVG contact is not faulty; if neces-
sary, replace it (
“BF”
version).
– Check the ignition wire is not faulty and that the con-
tact is good on the connection terminals.
– The electrode may be ill-positioned or require replace-
ment because it is broken.
– Electrical ignition A does not work; replace (
“BF”
ver-
sion).
– Piezo-ignition does not work; replace.
– Check the pilot flame hits the thermocouple adequa-
tely.
– Adjust gas flow to pilot.
– Safety thermostat may be faulty; replace.
– Replace interrupted thermocouple.
– Replace gas valve.
– Check water pressure switch PA; if necessary, repla-
ce it.
– The smoke thermostat has tripped; reset it.
– Check whether electric power is reaching the gas
valve actuator; check its operation and, if necessary,
replace it.
– Check operation of limit thermostat TL and smoke
pressure switch PF (
“BF”
version).
– The fan V is operating but at low rpm, so failing to acti-
vate the fume pressure switch PF (
“BF”
version);
replace fan.
– If, notwithstanding the checks listed above, the main
burner stills fails to start, replace the electronic card.
– Check that during electric wiring the position of line
and neutral have not been inverted.
– Check whether the equipment has a burnt fuse.
– Sensing electrode is faulty; replace.
– Equipment is faulty; replace.
– SS sensor is interrupted; replace.
– Modulator M has a break in winding; replace
– Electronic card is faulty; replace.
– SM sensor is interrupted; replace.
– Check that the pressure switch valve piston moves
properly activating microswitch at end of stroke. If this
does not happen, check that the water pressure corre-
sponds to the minimum specified; if necessary, repla-
ce pressure switch valve.
– The microswitch of the pressure switch valve is faulty;
replace it.
3.10
FAULT FINDING
