6 Commissioning

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, byhand, 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 arean aid to fault finding, for details refer to Section 9.

TOPSEALSIDESEAL

40814140a

NOTE: MAKE SUREOF CORRECT ENGAGEMENT

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 pumpingover 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

WINGNUTWASHER NUT

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

Diagram 6.5

o C between the flowand return.UNDER NO CIRCUMSTANCES SHOULD THIS VALVE BELEFT 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 coincidewith 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.

Diagram 6.6CONTROLSCOVERSLIDERS

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 thebalancing is satisfactory, making adjustments as necessary. Fit the front cover by hooking it under at the top and securingwith the wing nut, washer and nut previously removed, see diagram 6.5Fit the controls cover by hooking into the sliders and pushing itback as far as it will go, see diagram 6.6.
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