23
221966B
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 “Off” position, by hand,
wait at least 30 seconds before turning “On” again.
There may be an initial smell given off from the boiler, this is
quite normal and will disappear after a short period of time.
Refit the electrical controls box, see diagram 7.1.
Note. The neon indicators on the printed circuit board are an aid
to fault finding, for details refer to Section 11.
8.6 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.
8.7 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.
Diagram 8.4
GAS
PRESSURE
ADJUSTMENT
SCREW
MAIN BURNER
PRESSURE TEST SCREW
NOTE:
DO NOT ADJUST ANY
OTHER SETTING SCREWS
MULTI-
FUNCTIONAL
CONTROL
4294
8 Commissioning
Diagram 8.6
Diagram 8.5
CONTROLS
COVER
SLIDERS
SIDE
SEAL
TOP
SEAL
NUT
FRONT
COVER
WASHER
WING
NUT
RETAINING
CLIP
4295
4140
8.8 Sealed Water System ONLY
Adjust system to initial design pressure. The set pointer on the
pressure gauge should be set to coincide with the indicating
pointer.
8.9 Thermostatic Radiator Valves
If thermostatic radiator valves are fitted care must be taken to
ensure that an adequate flow rate through the boiler when they
close, refer to the current issue of BS7478 for guidance.
