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WD51/2/1997 Chapter 2 - Boiler Connections
Water treatment must be carried out to BS 7593 : Treatment of Water in Hot Water
Central Heating Systems.
Pump isolating valves must be positioned as close to the pump as possible.
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2.7.1
Installation & Servicing Instructions
The Keston 170 is suitable for use on open vented water systems with combined
feed and vent.
It is preferable for use on sealed water systems, provided the appropriate
components required (see Section 2.7.2 Sealed Systems) are included in the
system.
Any system must be thoroughly flushed clean of grease, dirt and debris, prior to
connection with the boiler. A trap should be installed in the flow line to collect any
solder, or other debris, from the installation.
All water systems must be constructed to comply with requirements of the Local
Water Authority.
Only fully pumped systems can be used - gravity systems are strictly not suitable.
Always use a system complying with the requirements of BS 5449 and BS 6798.
The system must be so arranged that there shall always be a minimum flow of
13.2 gpm (60 litres/min) when the boiler is firing.
installed by-pass arrangement.
Copper tubing to BS 2871 Part 1 is recommended.
Jointing should be either with capillary, threaded or compression fittings. Pipes
should have a gradient to ensure air is passed easily to vent points and water
flows readily to drain points.
Draining taps must be located in accessible positions which permit the draining of
the boiler and hot water storage vessel. Draining taps should be at least 22 mm in
nominal size and be in accordance with BS 2879.
AIR VENT POINTS
These must be fitted at all high points where air will naturally collect and must be
sited to allow complete draining of the system.
Open Vented Systems
A typical system is shown in Figure 2.7.1 which includes a combined feed and
vent. Note there must be no valve between the boiler flow and the open vent.
Note that the minimum static head required is 9 ft at the boiler flow pipe. If the
cold feed/vent is not brought to the flow pipe as shown, then the pressure loss
across the heat exchanger may have to be taken into account when estimating
the static pressure.
Although suitable for open vented systems with combined feed and vent
arrangements, the Keston is a low water content boiler. As such, any air
entrainement within the system water will produce boiler "kettling". It is
therefore recommended, if in any doubt, to consider the use of sealed
systems where possible.
The Keston 170 Condensing Boiler
This can be via a specially
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