24
221657C
6 Commissioning
Diagram 6.5
Diagram 6.6
CONTROLS
COVER
SLIDERS
WING
NUT
WASHER
TOP
SEAL
SIDE
SEAL
NOTE: MAKE SURE
OF CORRECT
ENGAGEMENT
NUT
4081
4140
burner has lit, making sure that all other gas burning appliances
and pilot lights are off.
Turn the control thermostat knob fully anticlockwise to “Off”.
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 System
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 then 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.
6.8 Sealed Water Systems ONLY
Adjust the system to initial design pressure.
The set pointer on the pressure gauge should be set to coincide
with the indicating pointer.
6.9 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.
6.10 Protection Against Freezing
If the boiler is to be out of use for a period of time during severe
weather conditions we recommend that the whole of the system,
including the boiler, be drained off to avoid the risk of freezing
up.
6.11 Operational Checks and Completion
Adjust the boiler thermostat and any system controls to their
required settings.
Do not attempt to adjust the thermostat calibration screw.
Operate the boiler again on full service and check that the
balancing is satisfactory, making adjustments as necessary.
Fit the front cover by hooking it under at the top and securing
with the wing nut, washer and nut previously removed, see
diagram 6.5
Fit the controls cover by hooking into the sliders and pushing it
back as far as it will go, see diagram 6.6.
