Unigas HTP90A, Installation, User'S, And Maintenance Manual, Page: 26 / 60

C.I.B. UNIGAS - M039219CA
26
ADJUSTING AIR AND GAS FLOW RATES
Gas Filter
The gas filters remove the dust particles that are present in the gas, and prevent the elements at risk (e.g.: burners, counters and regu-
lators) from becoming rapidly blocked. The filter is normally installed upstream from all the control and on-off devices.
Actuators
Two actuator models can be provided:
z
Berger STM30.. (see page 28) or
z
Siemens SQL33.. (see page 29).
Fig. 27
Keys
1 Gas filter
2 Gas proving system
3 Gas valves
4 Adjusting cam
5 Actuator
VPS504 Gas proving system
The VPS504 check the operation of the seal of the gas shut
off valves. This check is carried out as soon as the boiler
thermostat gives a start signal to the burner, creating, 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 supply point PA.
If the test cycle is satisfactory, after a few seconds the con-
sent 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.
Fig. 28
3
4
5
1
2
LC
LB
PA