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Start the heater and using a suitable
screwdriver adjust the pressure regulator,
turning the screw clockwise to increase the
pressure or counter-clockwise to decrease the
pressure.
Set the pressure to appropriate inches w.c.
from the table of gas pressures and orifice plate
dimensions for correct heater description.
Switch off the power supply to the heating
system. Disconnect ‘U’ tube manometer, then
secure screw in pressure test nipple.
Check the operation of the flame safeguard
equipment as follows:
With the heater running normally, switch off the
gas supply at the shut off valve. The heater
should attempt to relight. If the gas valve has
been left off, ‘lock-out’ should occur. This is
indicated by the ‘power on’ lamp being
illuminated and fan running, but the ‘burner on’
lamp being off.
Check the operation of the pressure proving
switch as follows:
With the heater running normally, pull off the
silicone rubber tube connecting the vacuum
switch to the combustion chamber. Within 4
seconds the burner should shut off.
Then replace the tube securely and observe
that the heater proceeds to ignite in the normal
way.
Close the controls door securing it with the
screw.
