Unigas N1300A, Manual Of Installation - Use - Maintenance

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PART II: INSTALLATION
20
Integrated proving system (burners equipped with LME7x, LMV, LDU)
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 .
This paragraph describes the integrated proving system operation sequence:

At the beginning both the valves (EV1 and EV2) must be closed.

Test space evacuating: EV2 valve (burner side) opens and keep this position for a preset
time (td4), in order the bring the test space to ambient pressure.Test atmospheric pressure:
EV2 closes and keep this position for a preset time (test time td1). The pressure switch
PGCP has not to detect a rise of pressure.

Test space filling: EV1 opens and keep this position for a preset time (td3), in order to fill the
test space.

Test gas pressure: EV1 closes and keep this position for a preset time (td2). The pressure
switch PGCP has not to detect a pressure drop down.
If all of the test phases are passed the proving system test is successful, if not a burner lockout
happens.
On LMV5x and LMV2x/3x and LME73 (except LME73.831BC), the valve proving can be
parameterized to take place on startup, shutdown, or both.
On LME73.831BC the valve proving is parameterized to take place on startup only.
PS
EV1 EV2
/
EV2
EV1
PGCP
LC
LB
PA