joule Thermalstore 1.0, Installation Manual

Page: 10 / 68

Thermalstore
10
FITTING THE INLET CONTROL GROUP
Excess pressure can lead to the DHW coil bursting. Make sure that there is suffi cient
space for future maintenance and also for connection of the discharge pipe for the
expansion relief valve.
It is essential that this connection is not covered or closed.
HOT WATER PIPEWORK
Run the first part of the hot water distribution pipework in 22mm. This can be
reduced to 15mm and 10mm as appropriate for the type of tap etc. Your aim should
be to reduce the volume of the hot draw-off pipework to a practical minimum so
that the time taken for the hot water is as quick as possible.
Do not use monobloc mixer tap or showers if the balanced cold connection is not
provided. Outlets of this type can back pressurise the unit and result in discharge.
EXPANSION VESSEL
The expansion vessel receives the increased water volume when expansion takes
place as the system heats up and it maintains a positive pressure in the system. The
expansion vessel contains a fl exible diaphragm, which is initially charged on one
side with nitrogen, but can be topped up with air when required.
The pipe connecting the expansion vessel to the system should have a diameter of
not less than 15mm and must not contain any restrictions.
Prior to connecting the expansion vessel to the system the pipework should be
fl ushed and tested. When the vessel is connected the system should be pressurised
when cold. If the initial system water pressure is too high, the diaphragm will be
displaced too far into the vessel. This will leave the vessel unable to accommodate
the volume of expansion water. The result of this is an increase in system pressure
and the safety valve will lift.