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We strongly advise that all installation pipework is run in copper. However, if plastic pipe is
used, it must be recommended by the pipe manufacturer for use with oil fired appliances
and, in any case, the last 1000mm of pipework connected directly to the appliance must be
of copper.
Whenever a pressure reducing valve or other device containing a non-return valve is fitted
to the mains water supply to the boiler, a mini expansion vessel must be fitted after the
device in order to protect the appliance from the expansion due to heating of the water in
the domestic hot water pipework
Note that the flow rate from individual taps is dependent on the number of outlets being
operated together, as well as the length and size of pipework and the mains supply
pressure.
10.3.2 Water Hardness
Although many of the DHW components are designed to resist lime scale formation, in
areas of hard water it may still be necessary to fit an inline chemical water softener. For
further information contact Warmflow and your local water company.
10.3.3 Boreholes
Where the mains water supply to the boiler is fed from a borehole via a pump and
accumulator arrangement the variable pressure can cause the mixer valve to go to its fail
safe settings thus preventing the outlet water temperature from achieving a suitable level. In
order to minimise the pressure variations it is recommended that differential on the borehole
pump pressure switch is kept as low as possible without adversely affecting the pump
motor. The accumulator must be as large as possible in order to reduce the rate of pressure
change and a pressure reducing valve (PRV) must be situated between the pump and
accumulator and the boiler. The PRV must be set slightly below the minimum setting of the
pressure switch on the pump.
10.3.4 Flow Restrictor
An 18L/min flow restrictor has been factory fitted but can be easily removed if required.
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