Useful Information; Gas Type Change; Switching From Gas In The Second Group To Gas In The Third Group - Accorroni MEC25-85 Technical Information

WARNING! When the burner turns off, the
fan(s) will continue to operate for a few
minutes, to properly cool the exchanger.
Therefore, it is important not to turn off the air
heater using the mains switch, that also cuts
off the power supply to the fan(s), since this
might lead to overheating and trip the safety
thermostat.
Then repeat the start-up operation to observe and
check that the burner has ignited correctly and
that the flame is stable. It is also necessary to
check the ignition of the second burner (model 85
only), which ignites at the same time as the first
one. The discharge of the ignition electrode in the
second burner will continue for about 30 seconds;
check that it operates correctly.
If the remote-control panel is installed, perform the
following test: while the air heater is not operating,
set the switch (A) to the bottom "ventilation"
position and check that causes the fan(s) to start
operating (summer ventilation).
If the MEC C series air heaters are installed with
warm air distribution ducts, operate the appliance
for at least 30 minutes. In the meantime, check that
warm air flows freely from the duct grilles or
outlets, under the foreseen design conditions.
Any obstructions, improper adjustments of the
outlets or incorrect dimensioning of the ducts
might cause the appliance to overheat, and trip
the safety thermostat. If this occurs, try to identify
and eliminate the possible causes of such
overheating.
Once the tests have been completed, close the air
heater service door(s) correctly.

5.3 USEFUL INFORMATION

It is recommended to inform the user about
all the operations necessary to use the air
heater correctly, with particular reference to
the ignition and shutdown phases and about
the importance of periodic tests, which must
be performed at least once every year by
skilled personnel.

6. GAS TYPE CHANGE

WARNING! The operations described below
must be carried out by skilled technical
personnel.
6.1 SWITCHING FROM GAS IN THE SECOND
GROUP (G20) TO GAS IN THE THIRD
GROUP (G30 - G31)
a) check that the envelope supplied with the air
heater contains the replacement injectors, with
the relative seal washers and the adhesive
label, on which to indicate the new type of gas
being used, to replace the original one, inside
the air heater service door.
- For the models 50 - 57 and 85 there is also
an aluminium diaphragm with calibrated
hole. The use of this diaphragm is
described in point f) below
b) check that the diameter of the injectors indicated
for the type of gas to be used (see technical
data table on page 18) corresponds to what is
stamped on the injectors
c) close the gas on-off valve and disconnect the
electric power supply
d) disassemble the injectors from the burner using
a 12 mm hex wrench (figures 24-25-26)
- Model 85 is equipped with two burners,
mounted in an opposing positions (see exploded
diagrams). To access the second burner it is
necessary to open the service door on the left
of the appliance. The operations to replace the
injectors of the aforementioned burner are
similar to those for the other models (fig. 27).
e) screw the new injectors into place, inserting
GAS INJECTOR REPLACEMENT (models 25-30-35)
Unscrew using a 12
mm hex wrench
Injectors
page 28
Gas unit
Burner
Pressure inlet
Fig. 24