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4
USE AND MAINTENANCE
4.1
GAS VALVE (fig. 19)
Boilers are normally produced with a
KROMSCHROEDER CG340Z gas valve.
4.2
GAS VALVE
ADJUSTMENT
The gas valve reduces power correspon-
ding to approximately 40% the rated power
before the burner shuts down completely
by means of the double contact adjustment
thermostat.
The maximum pressure and reduced pres-
sure are calibrated in the factory. It is the-
refore recommended not to change them.
Only when passing to another type of gas
(propane), in which case they may be chan-
ged complying with the values shown in
Ta ble 3.
This operation must be performed exclusi-
vely by authorised service technicians, or
the guarantee will be nullified.
Operations involved in adjustment of pressu-
re settings must be carried out in a certain
order, adjusting the maximum pressure first
and then the reduced pressure.
4.2.1
Adjusting maximum
and minimum pressure
Proceed as follows to calibrate the maxi-
mum pressure (fig. 19):
- Connect the column or a pressure gauge
to the pressure socket on the burner col-
lector.
– Turn on the boiler and after a short period
of operation at nominal power, slowly rota-
te the boiler thermostat knob towards the
minimum position until you hear the click of
the first thermostat contact; or remove the
connector 11 fig. 19 of the 2nd stage to bring
the boiler to a lower pressure value. At this
point, by turning the screw (8), find the mini-
mum pressure value shown in Table 3 for the
gas in question, using a 2.5 mm Allen key.
- Repeatedly activate the main switch, che-
cking the pressure corresponds to the set
value.
Calibrate the minimum pressure (fig. 19)
once the maximum pressure has been cali-
brated:
- Again use the column or a pressure gauge
to check the pressure.
- Turn on the boiler. After a short period
of time of its running at nominal power,
slowly turn the boiler thermostat knob to
minimum until a click is heard indicating
first thermostat contact.
- Leave the knob in that position and turn
the screw (8) to find the minimum pres-
sure value stated in Table 3 for the gas in
question.
- Repeatedly activate the main switch, che-
cking the pressure corresponds to the
established value.
56
2
10
1
KEY
1 Pressure inlet
2 EVG1 solenoid valve
3 Maximum pressure
adjustment screw
4 EVG2 solenoid valve
5 Pressure outlet
TABLE 3
Type of gas
Reduced burner pressure
Methane - G20
Propane - G31
4.2.2
Slow ignition adjustment
The gas valve opening speed can be adjusted
by turning the screw (6) to a value between
2.5 and 6.
4.3
SECOND GAS SOLENOID VALVE
The gas valve is manufactured as per stan-
dard complete with a second normally clo-
sed solenoid valve.
4.5
TRANSFORMATION TO
ANOTHER TYPE OF GAS
A kit is supplied containing everything requi-
red for transformation to propane gas (G31) .
To switch from one type of gas to another,
the main nozzles must be replaced and the
minimum gas pressure switch (9) calibrated:
17 mbar (G20) or 25 mbar (G31).
Proceed as specified in point 4.2.1 to adjust
operating pressures.
When finished, apply the plate provided in
the kit for identification of the gas for which
the boiler is set up to the skirt.
4
5
3
6
7
9
11
8
6 Slow ignition screw
7 Minimum pressure valve EVM
8 Minimum pressure adjustment screw
9 Minimum gas pressure switch
10 EVG1/EVG2 power plug
11 2nd stage control plug
mbar
6
15
NOTE: All gas connections must be tested for
seal using soapy water or products intended
for the pur pose after assembly. DO NOT USE
OPEN FLAME.
4.6
CLEANING AND
MAINTENANCE
At the end of the heating season, perform
boiler cleaning and maintenance as follows
(fig. 23):
– Turn off the power supply to the electrical
panel.
– Remove the skirt door (2) and baseboard
(1).
– Unhook the upper front panel (3)
hook it to the pins below it.
– Remove the cover (6).
– Remove the screw holding each burner (7)
in place and remove the burner from the
combustion chamber.
– Remove the screws holding the upper in-
side panel (4) in place.
– Remove the screws holding the cleaning
panel in place (5).
– Clean the flue gas passageways with a
brush.
Max. burner pressure
mbar
9,7
35
Fig. 19
and
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