Dibo SBH-G-D Mode D'emploi page 120

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C O M B U S T I O N C H A M B E R G A S H E AT E D I N S T R U C T I O N S - R E G U L AT I O N S
c. Due to the double casing the construction becomes very stable and extremely torsion safe.
Galvanized, powder coated steel sheet and stainless steel 1.4301 are the available materials.
2.4 Ventilator motor and ventilator wheel (Page 15, P. 21 and 25).
2.5 The combustion chamber is formed by an extremely heat resistant tube and diffusor reaching deeply into the flame area.
2.6 The insulation plate (Page 15, P. 9) made from oxide ceramic prevents the combustion chamber from burning out.
It absorbs condensation water. During operation of the burner it will evaporate immediately.
The insulating plate will not be damaged by these procedures. Change if working on the heating coil.
2.7 The safety device consists of:
Switch box with switch elements (P. 19-20),exhaust temperature limiter (S. 19, Pos.10)
firing automat (S. 19, Pos. 18), (digital)thermostat (S. 20 Pos. 20), safety valve (S. 15 Pos. 12),
flow switch (S. 15 Pos. 13) and pressure switch (S. 15 Pos. 11).
The safety device guarantees the safe operation of the burner and regulates the desired water temperature.
2.8 The ignition transformer (S. 15, Pos. 32) with 30 mA/8kV secondary current ensures high ignition capacity and
thus a safe start even under unfavourable conditions. It is being mounted outside the switch box at the switch box support
to achieve a better heat dissipation.
2.9 Gas valve (P. 15, Pos. 43),
The gas valve unit consists of the following parts:
1 solenoid valves, pressure controller – adjustment range 4 – 20 mbars,
1 gas pressure switch – adjustment range 2,5 – 50 mbars, 1 gas filter
The following elements can be exchanged in case of malfunction:
a) The housing of the magnetizing coil after loosening the two screws at the upper covering and pulling off of
the two connector plugs.
b) The gas pressure switch after pulling off the plug and loosening of two screws.
c) The filtering mat after removal of the filter flange.
d) The entire unit after loosening of the flange connection and pulling off of the connector plug.
2.10 Gas pressure control device
The gas pressure switch flanged to the right side of the gas valve registers the gas pressure between the gas filter
and the gas pressure regulator. The correct adjustment is 10 mbar.
Attention! The maximum thermal capacity can only be achieved by a flow pressure of 20 mbar.
Gas meter and pre-pressure reducer should guarantee the flow pressure.
If the gas pressure drops below 10 mbar, the gas valve will be closed or the burner does not start at all.
The pressure measurement should be tapped from No. 1 (page 11, picture 3).
2.11 Air pressure control device
The air pressure switch is situated at the right top inside the switch box and is connected with the cover of the
combustions chamber by means of a blue measuring tube. (Page 15, P. 7).
The correct adjustment is 2 mbar. If the air pressure of the ventilator falls below 2 mbar, the gas valve will be closed.
The firing automat locks and sets off the fault message.
2.12 Flow switch
The flow control device (Page 15, P. 13) cuts off the burner in case of an insufficient water flow.
The cut off point is adjustable between 4 and 10 Litres/ min.
The adjustment may not be under 6 Litres/ min. Otherwise the formation of steam may be the result.
2.13 Gas firing automat (inside the switch box)
After a demand of heat the gas firing automat controls the burner motor, the ignition and the gas valve. The firing automat
regulates the time periods and controls the flame by means of ionization control. If either the ionization current, the air
pressure or the gas pressure is too low, the firing automat initiates the cut-off immediately. For details concerning the firing
automates see page 31-36.
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DiBO 24