Expansion Vessel; Cylinder; Method Of Make-Up For Sealed Systems; Mains Connection, Filling Point - Potterton Kingfisher Mf Installation & Service Instructions Manual

Expansion Vessel

A diaphragm type expansion vessel to BS 4814: Pt 1.
shall be fitted close to the inlet side of the pump. The
connecting pipework should not be less than 15mm.
Pipework connecting the expansion vessel should not
incorporate valves of any sort. Methods of supporting the
vessel are supplied by the vessel manufacturer. The
nitrogen or air charge pressure of the expansion vessel
shall not be less than the hydrostatic head, (height of the
top point of the system above the expansion vessel).
To size the expansion vessel it is first necessary to
calculate the volume of water in the system in litres. The
following volumes may be used as a conservative guide
to calculating the system volume.
Boiler Heat Exchanger:
Small Bore Pipework:
Micro Bore Pipework:
Steel Panel Radiators:
Low Water Capacity Radiators: 2 litres per kW of
Hot Water Cylinder:
If the system is extended, the expansion vessel volume
may have to be increased unless provision has been
made for extension.
Where a vessel of the calculated size is not available, the
next available larger size should be used.
The boiler flow temperature
approximately 82°C.
The vessel size can now be determined from the
information in Table 4 where V = System volume in litres.
Vessel Charge Pressure (bar)
Initial System Pressure (bar)
Expansion Vessel Volume (litres)
12 Installation Requirements
6.5 litres
1 litre per kW of system
output
7 litres
8 litres per kW of
system output
system output
2 litres
is controlled
0.5
1.0
V x 0.11 V x 0.087
Table 4.

Cylinder

The hot water cylinder must be an indirect coil type or a
direct cylinder fitted with an immersion calorifier suitable
for operating at a gauge pressure of 0.3 bar (5 lbf/in≈) in
excess of safety valve setting. Single feed indirect
cylinders are not suitable for sealed systems.

Method of Make-up for sealed systems

An alternative method of replacing water lost from the
system could be provided by means of a make up vessel
of not more than 3 litres capacity, mounted above the
highest point of the system.
Mains Connection
There shall be no connection to the mains water supply
or to the water storage tank which supplies domestic hot
water even though a non-return valve, without the
approval of the Local Water Authority.
Filling Point
A filling point connection on the central heating return
pipework must be provided to facilitate initial filling and
pressurising and also any subsequent water loss
replacement/refilling.
The sealed primary circuits may be filled or replenished
by means of a temporary connection between the circuit
and a supply pipe, provided a 'Listed' double check valve
or some other no less effective backflow prevention
device is permanently connected at the inlet to the circuit
and the temporary connection is removed after use.
The filling method adopted must be in accordance with
at all relevant water supply regulations and use approved
equipment.
Your attention is drawn to, for GB: Guidance G24.2 and
recommendation R24.2 of the Water Regulations Guide.
for IE: the current edition of I.S. 813 "Domestic Gas
Installations".
1.0
1.0
Filling Point Requirements
Fig.7
Double
Stop
Stop
Check
Valve Valve
Valve
Temporary
Hose
DHW
Mains Inlet
CH
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Publication No. 5102977