Domestic Hot Water - Worcester Combi RSF 240 Installation And Servicing Instructions

9. Domestic Hot Water
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9.1 The following are general requirements and, if necessary,
reference should be made to the local Water Company before
fitting the appliance.
9.2 MAINS COLD WATER INLET. Devices capable of preventing
the flow of expansion water must not be fitted unless separate
arrangements have been made. An expansion vessel connection
point (Rc'/2) is provided adjacent to the flow switch within the
appliance.
A Zilmet 2160 expansion vessel is the preferred type. A thread
sealant compatible with potable water must be used.
9.3
The final 600 mm of the mains cold water connection to the
appliance should be made in copper tube only.
9.4
The appliance is suitable for a mains pressure of up to 10
bar (150 lb/in').
9.5
The appliance is fitted with a mains supply isolating valve.
9.6
The maximum domestic hot water flow rate is 8.5
litres/min. ( ± 15%) (1 .87 gallons/min.).
9.7
In winter (when the mains inlet water temperature is lower)
a reduced flow rate at the taps will be required to achieve the
maximum hot water delivery temperature available in warmer
weather.
9.8 It is a requirement that long pipe runs to the taps or shower
should be insulated to prevent the rapid cooling of domestic hot
water after a tap or shower has been turned off. Refer to
BS5546:1990.
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9.9 Hot and cold taps and mixing valves used with this appli-
ance must be suitable for operating at a pressure of up to 1 0 bar
(150 lb/in').
9.10 No anti-syphonage arrangements are necessary except for
some loose head showers. See also Section 9.11 following.
9.11 Thermostatically controlled or pressure equalising shower
valves will guard against the flow of water at too high a temper-
ature.
9.12
The head of a loose head shower must not fall closer than
25 mm (1 in.) above the top edge of the bath to prevent its
immersion in bath water. Alternatively the shower must be fit-
ted with an anti-syphonage device at the point of the flexible
hose connections.
9.13
The supply of hot and cold mains water direct to a bidet is
permitted, (subject to local Water Company requirements), pro-
vided that the bidet is of the over-rim flushing type. The outlet(s)
should be shrouded and unable to have any temporary hand
held spray attached. No anti-syphonage arrangements are nec-
essary.
9.14
As the maximum temperature of the Water to Water heat
exchanger is limited by the control circuit, there is normally no
need for water treatment to prevent scale accumulation. In
exceptional circumstances a device to prevent scale formation
can be fitted.
Installation of a scale inhibitor assembly should be in accor-
dance with the requirements of the local Water Company. An
isolating valve should be fitted to allow servicing. The water
hardness can be determined using a standard test paper or by
reference to the local Water Company.