Alpha Alpha CB24, Installation And Servicing Instructions, Page: 15 / 36

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When commissioning the boiler, ensure the Benchmark Log Book is completed.
5.1 FILL THE SYSTEM
1. The boiler is fitted with an automatic air vent positioned on the pump (see Fig. 2). The vent is always open and has no
sealing cap.
2. Open the central heating flow and return valves (slot in-line with valve) (see Fig. 11).
3. Open the fill point valve on the filling loop until water is heard to flow. To aid venting, the boiler drain point (see Fig. 2) may
be opened until water flows out. Close the drain point as soon as water appears.
4. To remove the air - Vent each radiator in turn, starting with the lowest in the system.
5. It is important that the pump is properly vented to avoid it running dry and damaging its bearings. Unscrew and remove the cap
from the centre of the pump. Using a suitable screwdriver rotate the exposed spindle about half a turn, then replace the cap.
6. Check the operation of the pressure relief valve (see Fig. 2) by turning the head anti-clockwise until it clicks. The click is
the valve lifting off its seat allowing water to escape from the system - check that this is actually happening.
7. Continue to fill the system until the pressure gauge indicates 1.0 bar. Close the fill point valve and check the system for
water soundness, rectifying where necessary. Disconnect the filling loop from the mains supply.
Water may be released from the system by manually operating the drain point (see Fig. 2) until the system design
pressure is obtained. The system design pressure (cold) should be between 0.75 and 1.25 bar.
Refer to sections 3.7 and 3.8. System volume and Filling the system.
8. Open the mains water inlet valve (see Fig. 11). Turn on all hot water taps and allow water to flow until no air is present.
Turn off taps.
5.2 BOILER CONTROLS - Fig. 16
Alpha CB24/28 - Commissioning
Fig. 15
5 COMMISSIONING
Fig. 16