Fig. 4.8 - External soakaway
Alpha E-Tec Plus 28 and 33 - General Boiler Information
Ground level (either/or)
22mm termination from boiler, increase to 32 mm if external
2½ fall
O
25mm
300mm
Two rows of 3 x 12mm
holes at 25mm centres,
50mm from the bottom
of the tube. Holes to face
away from house.
Cement mortar sealing
100mm plastic tube
Bottom of tube sealed
Soakaway depth 400mm
filled with limestone chippings
500 mm min.
4.11 DOMESTIC HOT WATER SYSTEM
The minimum flow rate needed for the flow switch and burner to operate is 1.5 litres/min.
If the incoming mains water pressure is above 5 bar a pressure reducing valve must be fitted.
If the mains supply is fitted with a water meter, check valves or loose jumper stop cock, then a DHW expansion
device must be fitted.
Following Part L Building Regulations, where the mains water hardness exceeds 200 parts per million, provision should
be made to treat the feed water to the hot water circuit of combination boilers to reduce the rate of accumulation of limescale.
To ensure economic use, the pipe runs between the boiler and taps should be in 15 mm copper pipe and be as short as
possible. Where possible the pipework should be insulated to reduce heat loss.
All taps and mixing valves used with the hot water system must be suitable for operating at a mains pressure of up to 8 bar.
Showers - A shower may be used with the boiler if required.
If a loose or flexible head type shower is used it may require the fitting of a double check valve, to comply with Water Bye Law 17.
Bidets - No anti-syphonage arrangements are necessary, provided the outlets are shrouded and it is not possible to attach
a temporary hand held spray. A supply of direct mains fed hot and cold water is permitted provided the appliance is of the
over-rim flushing type.
Before the mains water supply pipe is connected to the boiler, it should be thoroughly flushed out to avoid the
danger of dirt or foreign matter entering the boiler.
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