PART III: OPERATION
44
Adjusting the combustion head
Only if necessary, change the combusiton head position: to let the burner operate at a lower output, loose the
VB
screw and move pro-
gressively back the combustion head towards the MIN position, by turning clockwise the
VRT
ring nut. Fasten
VB
screw when the
adjustment is accomplished.
Gas Proving System VPS504 (Option)
The VPS504 check the operation of the seal of the gas shut off valves. This check, carried out
as soon as the boiler thermostat gives a start signal to the burner, creates, by means of the
diaphragm pump inside it, a pressure in the test space of 20 mbar higher than the supply
pressure.
When wishing to monitor the test, install a pressure gauge ranged to that of the pressure sup-
ply point
PA
. If the test cycle is satisfactory, after a few seconds the consent light
LC
(yellow)
comes on. In the opposite case the lockout light
LB
(red) comes on. To restart it is necessary
to reset the appliance by pressing the illuminated pushbutton
LB
.
Attention! if it is necessary to change the head position, repeat the air and fuel adjustments described above.
VB
VRT
LC
LB
PA
Summary of Contents for KP91
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