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Connection from the supply to the heater must
also comply with the relevant regulations (see
section 1.0) and must have been purged and
soundness tested by an authorised engineer.
6.3.3 Ignition sequence
PRE START DRY RUN
In order to test that all controls are in good
working order, the control sequence should first
be tested with the gas supply turned
Off
.
Ensure gas isolating cock is in the
Off
position.
Warning
If during the following sequence of operations the
heater fails to operate correctly the fault should
be traced and rectified before proceeding, if
necessary referring to fault diagnosis section.
a)
Switch off the main electrical supply to the
heater.
b)
Turn off gas supply to the heater.
c)
Remove access panel (where applicable) and
connect manometers to the gas supply test point
and to the main burner test point.
d)
Ensure outlet louvres are correctly set.
e)
Ensure fan rotation is not impaired or
obstructed.
f)
Set room thermostat(s) to its lowest setting
g)
If a time switch is fitted ensure it is set to an
on period.
h)
Switch on electrical supply.
i)
Use leak tester to test for soundness on the
unions and pipework.
j)
Operate the heater through the installed
control system.
On start the signal will activate the flue venter for
a pre purge period and in turn will make the air
proving switch, once made, the air proving switch
will complete the circuit to the control box and
after a 30 second Delay the automatic control
should attempt light the burner, because the gas
is turned off and flame cannot be established,
the control box will go to LOCKOUT.
k)
Reset the control on completion of dry run.
l)
Open gas cock.
m)
Operate heater through installed control.
The flue venter will pre purge the heater and in
turn operate an air proving switch which
completes the electrical circuit to the control box
after a 30 second Delay the control will open the
gas solenoid valve and the main burner will light.
The flame can be observed at the burner
manifold, check that the burner is providing a
good flame i.e. even and stable.
n)
Check pressure readings on the manometers,
and continue to let the heater fire for ten minutes.
o)
When the fan starts ensure that the direction
of rotation is correct , and that the fan start is
within 2 minutes of burner ignition.
Caution
If the fan fails to operate within approximately 2
minutes and the heater goes to overheat it will
shut down through breaking the circuit to the gas
valve, the cause must be ascertained and
rectified before re-ignition.
Once the limit thermostat has tripped out it must
be manually reset to allow re-ignition to take
place.
p)
After ten minutes check burner head pressure
is as specification - adjust as necessary by
removal of the gas pressure adjustment cover,
and using a screwdriver turn the adjustment
screw on the governor as follows: Clockwise to
increase. Anti clockwise to decrease.
For Hi/Low and Modulation adjustment, refer to
the following procedures
IMPORTANT
Adjustments should be made by qualified
persons only.
If the appliance manufacturer supplies checkout
and/or service and maintenance instructions,
carefully follow them. If such instructions are not
provided, then follow the procedure as outlined
below.
Allow time for pressure to stabilize before making
adjustments.
It is recommended that the High-Low regulator is
operated a few times to ensure correct setting. It
should be prevented, that High-Low regulator is
exposed to unnecessary forces because of
wiring.
Remove the protective cap by putting a small
screw driver in one of the slots and lifting
carefully, while at the same time supporting the
cap opposite the screw driver.
Maximum pressure setting must first be
adjusted then minimum pressure setting can
be adjusted.
Any adjustment of maximum pressure setting
influences minimum pressure setting.
Never adjust the maximum setting above the
range specified.
Adjusting maximum pressure setting
6. Commissioning & Testing cont.