4.8
CLEANING AND
MAINTENANCE
At the end of each heating season, it is
essential to have the boiler thoroughly
checked and cleaned out.
Proceed as follows:
–Turn the main switch off to stop electric
power reaching the boiler and close the
gas feed cock.
–Remove the outer casing as described in
section 4.7.
–Remove the gas burner manifold unit
(fig. 30).
–To clean the burner, blow in a jet of air, so
as to remove any dust particles that may
have accumulated.
–Clean the heat exchanger, removing any
dust or residue from combustion.
–When cleaning the heat exchanger or
the burners, chemical products or steel
brushes MUST NOT BE USED.
– Make sure that the tops of the burners
with the holes are free from encrusta-
tions.
–Reassemble the items removed from
the boiler, making sure to follow the cor-
rect sequence.
–Check the chimney to make sure that
the flue is clean.
–Check operation of the equipment and
the main burner.
–Af ter assembly of all the gas connec-
tions, these must be tested for sound-
ness, using soapy water or appropriate
products.
DO NOT USE NAKED FLAMES.
–Do not use calcium chloride to treat the
plastic component during generator
maintenance.
Preventive maintenance and checking of
efficient operation of equipment and
safety devices must be carried out exclu-
sively by authorized technical personnel.
4.8.1
Cleaning the C.H.
water filter
(fig. 33)
To clean the filter, close the delivery/return
on/off taps, turn off the power to the con-
trol panel, remove the casing and empty the
boiler using the drain provided (9 fig. 7) until
the hydrometer shows “zero”. Place a con-
tainer for collection underneath the filter,
unscrew the cap and proceed to clean the
filter, removing impurities and limestone
deposits. Check the seal o-ring before reas-
sembling the cap with the filter
4.9
FAULT FINDING
The burner does not ignite and the circu-
lator is working.
–Check that the water pressure reads 1 -
1.2 bar.
–The flowmeter is faulty, replace it.
–The flow switch has been tripped becau-
se the heating circuit filter is obstructed
with impurities; it needs cleaning.
Main burner does not start either to draw
off D.H.W. or for heating.
–Check flowmeter; if necessary, replace it.
–The smoke stat has tripped; reset it.
–Check whether electric power is rea-
ching the gas valve actuator; check its
operation and, if necessary, replace it.
–Check operation of the smoke pressure
switch (
“BF”
vers.).
–The fan is operating but at low rpm, so
failing to activate the smoke pressure
switch (
“BF”
vers.); replace the fan.
–Replace the electronic card.
Boiler turns on, but after 10 seconds
“locks out”.
–Check that during electric wiring the
position of line and neutral have not been
inverted.
–The sensing electrode is faulty; replace it.
–The control box is faulty; replace it.
Gas valve fails to modulate in D.H.W. and
C.H. modes.
–The sensor is interrupted; replace it.
–The modulator has a break in winding;
replace it.
–Check that the current to the modulator
complies with the specifications
–The electronic card is faulty; replace it.
Main burner fails to start in D.H.W. pro-
duction mode.
–Unscrew completely the screw of the
pressure switch valve (5 fig. 7)
–Check that the filter on the pressure
switch valve inlet is clean (3 fig. 7).
–Mains water charge pressure is too low;
install water-lift system.
–The microswitch of the pressure switch
valve is faulty; replace it.
D.H.W. is very hot but at low flow rate.
–Exchanger or D.H.W. outlet pipe obstruc-
ted by lime deposits; remove encrusta-
tions.
D.H.W. potentiometer and heating poten-
tiometer fails to regulate properly.
–Check that the sensor in question is in
contact with the pipe; use silicone paste
to improve sensitivity.
–The sensor in question is faulty; replace.
Boiler is noisy or heat exchanger makes a
sizzling sound.
–Check whether circulation pump P is
obstructed; if necessary clear it out.
–Unclog impeller of circulation pump, clea-
ring away any impurities or sediments.
–Circulation pump is burnt out or has a
lower rpm than required; replace it.
–Check boiler output is adequat e for
actual needs of heating system.
Boiler safety valve keeps tripping.
–Check charge cock is closed. If it doesn’t
close properly, replace it.
– Check system cold charge pressure is not
too high; keep to recommended values.
–Check whether safety valve is out of cali-
bration; if necessary, replace it.
–Check whether the vessel is sufficiently
capacious to contain the water for the
system.
–Check preloading pressure of expansion
vessel.
–Replace expansion vessel if faulty.
Radiators fail to heat up in winter.
–The rotary switch is on “Summer”; swit-
ch to “Winter”.
–The room stat is set too low or needs
replacing because faulty.
–The electrical connections of the room
stat are wrong.
–The microswitch of diver tor valve is
faulty; replace it.
Main burner burns badly: flames too high,
deep yellow.
–Check that pressure of burner gas is
regular.
–Check burners are clean.
–Check coaxial assembly has been instal-
led correctly (
“BF”
vers.).
Smell of unburnt gases.
–Check boiler is properly clean.
–Check draught is sufficient.
–Check gas consumption is not too high.
Boiler operates but does not increase
temperature.
–Check gas consumption is not lower
than it should be.
–Check boiler is clean.
–Check boiler is sized in proportion to
system.
In the “FORMAT” boilers, upon demand for
D.H.W. or heating, fan fails to turn at max
speed.
–Make sure that the smoke pressure
switch is working and that the relative
contact is in the rest position.
–Check whet her connection tubes of
smoke pressure switch are obstructed
and, if necessary, clean away impurities
or condensate.
–The smoke pressure switch needs repla-
cing.
–Replace electronic board.
91
Fig. 33
