Switching From Gas In The Third Group To Gas In The Second Group; Gas Injector Replacement .................................................. - Models 50 - 57 - Accorroni MEC25-85 Technical Information

the new seal washers and completely tighten
to guarantee a proper gas seal (fig. 27)
f) (only for models 50 - 57) unscrew the gas
fitting on the burner, remove the gasket and
replace it with the calibrated diaphragm. The
diameter of the hole corresponds to: 7.1 mm for
model 50 and 7.6 mm for model 57. Make sure
that the diaphragm is in the exact position and
tighten the fitting nut (fig. 25).
(only for model 85) unscrew the fitting after
the gas unit, corresponding to the position of
the "T" fitting. Remove the gasket and replace
it with the calibrated diaphragm. The diameter
of the hole corresponds to: 9.6 mm. Make sure
that the diaphragm is in the exact position and
tighten the fitting nut (fig. 26).
g) use the pressure regulator screw, after having
removed the protection plug, tightening it
(clockwise) carefully at the limit switch. Replace
the protection plug
h) start the air heater according to what is indicated
in point 5.2
i) Insert the manometer into the upstream
pressure inlet on the burner (figures 15-16)
after having removed the closing screw. Check
that the supply pressure corresponds to what
is indicated in the technical data table. If the
gas supply pressure does not correspond to
the value indicated, use the pressure reducer
(second stage) installed externally to obtain
the correct value
l) remove the manometer and tighten the pressure
inlet screw
m)use a special spray or electronic leak detector
to identify any leaks in the gas circuit, with
GAS INJECTOR REPLACEMENT (models 50 - 57)
Unscrew using a 12
mm hex wrench
Injectors
Gas unit
Burner
Al gasket
Pressure inlet
Fig. 25
particular attention on the burner and gas unit
pressure inlets.
6.2 SWITCHING FROM GAS IN THE THIRD
GROUP (G30 - G31) TO GAS IN THE
SECOND GROUP (G20)
WARNING! For this gas type change operation
a new adapter kit is required and should be
requested from the authorised dealer. In fact,
it is recommended not to use the injectors
and the gaskets from the original supply,
since the seals might have deteriorated.
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 - 85 there is also an gasket with a diameter
of 24 x 18 mm
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)
GAS INJECTOR REPLACEMENT (model 85)
Unscrew using a 12
mm hex wrench
Injectors
page 29
Gas unit
Al gasket
Burner
Pressure inlet
Fig. 26