Roberts Gorden Blackheat BH15 UT Installation & Servicing Instructions Manual page 27

S S e e c c t t i i o o n n 8 8 . . O O p p e e r r a a t t i i n n g g t t h h e e S S y y s s t t e e m m
8 8 . . 1 1 D D E E T T A A I I L L E E D D S S E E Q Q U U E E N N C C E E
On connection of power supply the fan motor will start
creating a suction in the tube. Power is also supplied,
via a relay safety circuit, to the fan proving switch and
when suction is created, changes contacts to feed
power to the Automatic Control Unit. At this stage one
neon will light up.
8.1.1 Power to the control causes initiation of an approxi-
mate ten (10) seconds purge period following which
the solenoid valves open passing gas at a full rate to
the burner. At the same time a spark is created and
ignition should take place. If ignition of the gas is not
successful the spark will cease and the solenoid will
close after approximately ten (10) seconds. Lockout
will occur. If the gas is ignited, the detection circuit is
energised and switches off the ignition circuit. Both
neons will now light up indicating full running condi-
tion.
8.1.2 The heater will continue to run until the power supply
or gas supply is interrupted. Interruption of the electri-
cal supply results in the shutdown of the heater.
Restoration will restart the whole sequence.
Interruption of the gas supply results in loss of flame
followed by one attempt at reignition followed by lock-
out if unsuccessful.
8 8 . . 2 2 T T E E S S T T I I N N G G
Establish that a satisfactory purged gas supply and an
electrical supply is available to the heater. Ensure that
all time clocks and thermostats are set to call for heat.
8.2.1 With the gas supply cut off at the appliance isolating
cock and the electrical supply isolated by switching off
at the local switch and removing the appliance inlet
plug, open the control chamber secured by the centre
screw. Remove the sealing screw from the pressure
test point and remove the cover cap from the gover-
nor.
8.2.2 Turn on appliance isolating cock and connect appli-
ance electrical plug. Ensure that the timer or thermo-
stat, if fitted, are set to call for full gas rate. Switch on
at the local switch. The sequence as described should
take place. If not, refer to detailed fault finding
sequence. When flame is established, check the gas
pressure reading and adjust if necessary. See data
label.
8.2.3 Check the gas pressure at the outlet of the gas valve
to ensure minimum 8.7 mbar (3.5 in. w.g.) pressure
for G20 natural gas or 27 mbar (10.5 in. w.g.) pressure
for propane. See Section 2 for G25 and Butane set-
tings.
8.2.4 Switch off the electrical supply (shutting down the
heater), remove pressure gauge - refit pressure test-
point screw, ensuring a tight gas seal. Replace gover-
nor cover cap. Close burner side cover.
8 8 . . 3 3 S S Y Y S S T T E E M M C C H H E E C C K K S S
Switch on again at the local switch to ensure smooth
ignition. Carry out the following system checks.
8.3.1 When running turn off the gas supply at the appliance
isolating cock. The heater will immediately shut down
followed by one attempt at restoration followed by
lockout.
8.3.2 When running disconnect the fan plug from the
burner. The unit should shut down within three sec-
onds proving operation of the pressure switch.
8 8 . . 4 4 U U S S E E R R I I N N S S T T R R U U C C T T I I O O N N S S
Having satisfactorily tested these Blackheat units
ensure that the client is fully aware of the operation of
the system. Bring this manual to the attention of the
user or purchaser; instruct them in the safe operation
of the heater(s). Advise the user that if the system is
unflued, any reduction in the natural ventilation of the
building may require a flue to be fitted, or additional
ventilation grills will be required.
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