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220683B
6.4 Testing - Electrical
Turn the boiler thermostat knob fully clockwise to the
maximum setting, which is about 82
o
C (180
o
F), neon 2
will light.
The lighting sequence is automatic as follows:
The fan operates
The spark ignition operates
Neon 3 will light
The pilot solenoid opens
The pilot burner lights
The ignition spark stops
The main solenoid opens
and after a short period of time the main burner will
light, look through viewing window, see diagram 6.3.
Very cold weather may delay the operating sequence.
1. With the main burner alight, turn the gas service cock
“Off”, see diagram 6.1.
After a short period the main burner and pilot will go
out.
2. The correct working of the flame supervision device
is shown by neon 4 going out within 10 seconds and the
ignition starting up.
Neons 1, 2 and 3 should stay alight.
3. If the above does not happen, refer to fault finding
Section 9.1.
4. To carry on turn gas service cock “On” see
diagram 6.1.
When the boiler switches “Off”, both the pilot and main
burner go out. The automatic lighting sequence will
work again when heat is required.
6.5 Testing - Gas
With the boiler on proceed as follows:
Test for gas soundness around the boiler gas components
using a suitable leak detection fluid, in accordance with
the current issue of BS6891.
Check the main burner gas pressure at least 10 minutes
after the boiler has lit, refer to Data Label.
If necessary adjust the gas pressure to obtain the required
setting turning screw clockwise, to decrease pressure, see
diagram 6.2.
Should any doubt exist about the gas rate, check it using
the gas meter test dial and stop watch, at least 10 minutes
after the burner has lit, making sure that all gas burning
appliances and pilot lights are off.
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Neon 4 will light
Turn the control thermostat knob fully anticlockwise to
“O”. Remove the pressure gauge from the test point and
refit screw, making sure a gas tight seal is made.
When the control thermostat is turned to the “Off”
position, by hand, wait at least 30 seconds before turning
“On” again.
There may be an initial smell given off from the boiler
when new, this is quite normal and it will disappear after
a short period of time.
Refit the electrical controls box, see diagram 5.8.
Note. The neon indicator lights on the printed circuit
board are an aid to fault finding, for details refer to
Section 9.
6.6 Testing - Open Vented
Allow the system to reach maximum working
temperature and examine for water leaks.
There should be no undue noise in the system and no
pumping over of water or entry of air at the open vent
above the feed and expansion cistern.
All systems - The boiler should be turned off and the
system drained off as rapidly as possible, whilst still hot.
6.7 Adjustment - Fully Pumped Open
Vented and Sealed Water Systems
When commissioning the system the boiler should first
be fired with the bypass fully closed on full service, that
is, central heating and domestic hot water. Adjust the
pump to the system design setting then balance the
system. Having achieved a satisfactory condition
operate the boiler with the bypass fully closed on
minimum load, normally this will be central heating only
with one radiator in the main living area operating.
The bypass valve should be gradually opened to achieve
a temperature difference no greater than 20
o
C between
the flow and return.
UNDER NO CIRCUMSTANCES SHOULD THIS
VALVE BE LEFT IN THE FULLY CLOSED
POSITION.
6 C o m m i s s i o n i n g
