32
ROUTINE YEARLY VERIFICATION OPERATIONS
cOMPOnEnT:
VERIFY:
cOnTROl/InTERVEnTIOn METh
-
Od:
VG
(Gas valve)
( 3 )
Does the valve modulate properly?
The verification is performed on the
“Calibration” requiring 100%, in 50%,
the minimum percentage of modula-
tion.
Make sure that the flame modulate.
SR (heating sensor)
( 11 )
SS (domestic hot water sensor)
( 1 )
Do the sensors maintain the
original characteristics?
12571 ohm at 20° C / 1762 ohm at
70° C.
Measurement to be taken with the
wires disconnected (see table Res/
Temp).
E ACC/RIV. (ignition/detection elec-
trode)
( 4 )
Does the discharge of sparks before
putting the boiler in safe conditions last less
than 10 sec.?
Detach the electrode ionisation wire
and check the securing time.
TL (anti-overheating
limit thermostat)
( 10 )
Does the TL put the boiler in safety conditions
when overheating?
Heat the TL until it intervenes at 102°C
and check that it intervenes at 102°.
DK (safety pressure switch against
water deficiency)
( 13 )
Does the pressure switch block the boiler
if the water pressure is below 0.4 bar?
Without request: close the shut-off valves
of the heating circuit, open the drain
valve to make the water pressure de
-
crease. Before pressurising again, check
the pressure of the expansion vessel.
Condensation drain trap
(27)
Has the trap got deposits on the bottom?
Clean the trap with water.
Heat exchanger body
( 9 )
1) Measure the Thermal Capacity using a me-
ter and compare the value with that contained
in table 3.12. The data measured indicates if
the exchanger needs cleaning.
2) Check that the space between the rungs of
the exchanger are not clogged
It is recommended to use the products
purposely created by Unical (see sys-
tem protection ACCESSORIES sect. in
the domestic price list), being careful
to wash the area with most rungs first
(lowest part visible from above) and
then the upper part if necessary.
Burner
( 5 )
Check the state of cleanliness of the burner
mesh
Remove any deposits using com
-
pressed air, blowing from the mesh
side.
( Num ) =
see key Par. 2.2
