20
24.- CHANGING TO A DIFFERENT TYPE OF GAS
Should a different gas be used from the gas for which
the boiler has been equipped, the following parts
must be replaced.
Burner injectors (12).
Burner pressure must be regulated.
These modifications, together with the regulating
process, must only be carried out either by the
Technical Assistance Service or by a qualified expert.
Remove the front panel. As it will be held in place
by means of four fastening bolts, pull it off to remove
it. Remove the front panel of the close chamber.
Unscrew the 8 screws from the front panel of the
combustion chamber and then remove it.
Unscrew the four screws from the electronic box.
There are two screws on the front and another two at
the bottom of the unit. Move down the electronic box.
Remove the flame sensing electrode and the igni-
tion plug conectors.
Unscrew the four screws (A) which hold the manifold onto the burner. Remove the manifold
Unscrew the hexagonal screw (B) which hold the
manifold to the gas valve.
Change 12 burner injectors (see chart 1).
Put the manifold in place. Put the flame sensing
electrode and the ignition plug conectors in place.
Put the front panel of the combustion chamber and
the front panel of the close chamber.
To adjust the pressures of the burner to the new
type of gas, proceed as follows:
Take off the plastic cover (D) of the electronic box.
The bridge S4:
- For LPG must be connected
- For natural gas must be disconnected
Dismantle the protective hood C (see gas valve
details 1) of the gas valve and set the burner in
D.H.W.
Set the maximun Output:
Set the D.H.W. temperature selector at maximum.
Place the variable resistance of the electronic card
P1 (see figure 3) in the maximum position (rotate
clockwise).
Open a D.H.W. tap.
Adjust the burner maximum pressure (see chart 2).
Using a hexagonal spanner rotate the screw E of the
gas valve (see gas valve details 2). Rotating clockwise the pressure increases.
Act on the variable resistance P1 rotating it anticlockwise until the burner pressure gets the same
value as what we got on the mechanical adjustment.
Set the minimal pressure
Open a D.H.W. tap.
Adjust the burner minimal pressure (see chart 2).
Disconnect one of the modulating electrovalve terminals (electrovalve on which you are acting) of the gas
valve.
Adjust burner pressure to the value indicated in
chart 2 rotating the hexagonal screw E. Maintaining
blocked the hexagonal screw E rotate the star screw
T (see figure 2). Rotating clockwise the pressure
increases.
Once concluded the minimal output setting operation,
connect the terminal again.
Adjust the starting pressure acting on the variable
resistance P2 (rotating clockwise the pressure
increases). It is 4 mbar in natural gas, and 8 mbar. in
LPG. To make this operation you have to:
Disconnect the air connection of the ionisation
22.- FROST PROTECTION
23.- ANTI PUMP SEIZURE DEVICE
The boiler has an frost protection security system.
IMPORTANT: the boiler must be electrically
supplied and gas connected for this to operate.
Frost protection
When the heating thermistor detects a temperature of
6ºC, only the pump will switch and will continue to run
until a temperature of 9ºC is obtained.
If the temperature drops to 3ºC, the boiler will start on
minimum power until the temperature of 20ºC is
obtained.
NOTE: If the boiler is not to be used for a long period drain the heating installation using the valve (Z)
beneath the boiler and the D.H.W. installation.
The D.H.W circuit must be drained down as follows:
Turn off the cold water supply.
Open all the hot water outlet taps in the installation
(at least one tap should be found at a level lower than
the boiler).
Release the tap to drain the flow switch to allow air
to come in and for the stored water in the boiler to be
able to leave.(see figure)
When the operation is finished, close the hot water
outlet taps and the draining tap.
To put the boiler back into service, open the cold
water inlet tap.
When the boiler is not being used, the pump will automatically run for one minute every 24 hours to prevent seizure. TO ENSURE OPERATION OF THIS
DEVICE ELECTRICAL SUPPLIES MUST BE ON.
If the pump jammed when the appliance is turned
back on, consult your installer or service engineer.
Z