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7.3.
System Piping Layout Design
7.3.1.
Design Considerations
The boiler must be installed by a certified plumber or heating engineer and systems. Systems are to be designed to
meet the current building regulations. EHS Limited are not responsible for faulty installations or installations that are
made by unqualified people.
HEATING EXPANSION VESSEL
A 5ltr expansion vessel is fitted internally within the boiler to provide room for
thermal expansion of water under regular operating conditions. If the system contains significant volumes of water,
an additional heating expansion vessel conforming to the current issue of BS4814 should be fitted externally. For any
system an accurate calculation of vessel size is given in the current issue of BS5449 and BS7074 part 1.
AUTOMATIC BYPASS VALVE
An automatic bypass valve
MUST
be installed as part of this installation. The ABV
should be fitted to begin opening immediately the first radiator, valve or actuator shuts in the system. This stops
excess pressure from building in the system on the flow side.
Failure to fit and set the ABV can result in poor
performance and premature boiler failure
ISOLATION VALVES:
EHS recommend that
full bore isolation valves
are fitted on the flow and return pipework from
the boiler. Standard ball valves will restrict flow and impede the flow in and out of the boiler which will result in poor
performance.
AUTOMATIC AIRVENTS:
The EHS Boilers have a built-in automatic air vent. If, however, the boiler is to be used
alongside a hot water cylinder, you should fit an additional air vent in the vicinity of the cylinder coil.
SYSTEM FILLING:
A WRAS approved filling loop must be used in such a way that it never becomes a permanent
connection between the mains water and the heating system. There is a fill point on the boiler called a ‘water
replenishing valve’. A temporary connection can be made to this to fill the system or top up the pressure.
Alternatively, this can be left closed, and a traditional filling loop installed. The heating system should be filled to
1.5bar when cold and topped up accordingly during commissioning. Please refer to BS EN 14336.
MAGNETIC FILTER:
An inline magnetic filter should be fitted on the return side of the heating circuit to protect the
boiler from debris from the heating system. This should be checked at every service interval or before if there is poor
flow in the system. Failing to fit a magnetic filter will affect the warranty.
DRAIN POINT
A drain point should be fitted at the lowest point of the heating system. It is not acceptable to drain
the boiler through a safety valve as debris can prevent the correct operation of the valve
