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.
A mini expansion vessel kit is available which contains the
necessary parts for fitting an internal expansion vessel to the
appliance.
Refer to Section 19.
A thread sealant compatible with potable water must be used.
An external expansion vessel may be fitted on the mains cold
water connection to the appliance.
9.3
The final 600mm 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
2
) and is fitted with a mains supply isolating valve.
9.5
The maximum domestic hot water flow rate is 11.4
litres/min (±15%).
9.6
In winter (when the mains inlet water temperature is lower) a
reduced flow rate at the taps may be required to achieve the
type of hot water delivery temperature available in warmer
weather.
9.7
It is suggested 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.
9.8
Hot and cold taps and mixing valves used with this
appliance must be suitable for operating at mains pressure and
temperatures of 55°C.
Note:
The maximum domestic hot water outlet temperature is
fixed at 55°C and it is not adjustable.
9.9
No anti-syphonage arrangements are necessary except for
some loose head showers. See also Section 9.11 following.
9.10
Thermostatically controlled or pressure equalising shower
valves will guard against the flow of water at too high a
temperature.
9.11
The head of a loose head shower must not fall closer than
25mm (1in.) above the top edge of the bath to prevent its
immersion in bath water. Alternatively the shower must be fitted
with an anti-syphonage device at the point of the flexible hose
connections.
9.12
The supply of hot and cold mains water direct to a bidet is
permitted, (subject to local water company requirements),
provided 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
necessary.
9.13 LIME SCALE. In temporary hard water areas (more than
350mg/litre or 200ppm calcium bicarbonate) it is
recommended that a proprietary scale reducer is fitted in the
mains cold water connection to the appliance. Consult the
local water company for additional advice.
Installation of a scale inhibitor assembly should be in
accordance with the requirements of the local water
company. An isolating valve should be fitted to allow
servicing. The water hardness can be determined by
reference to the local water company.
9.14 NOTE: HOT WATER ONLY.
If required the appliance may be used for Hot Water only
before the Central Heating is connected. A 22mm copper by-
pass pipe at least 4 metres long must be connected between
the Central Heating Flow and Return, but it is advisable to
connect a small radiator instead.
IT IS NOT RECOMMENDED TO USE THE BOILER IN THIS
CONDITION FOR EXTENDED PERIODS.
The boiler requires 3.17m
3
/h (112ft
3
/hr) of natural gas with a
calorific valueof 37.78MJ/m
3
. The meter govenor should deliver
a dynamic pressure of 20 mbar (8in w.g.) at the appliance,
equivalent to a pressure of 19-19.5 mbar at the gas valve on
natural gas.
The gas meter and supply pipes must be capable of supplying
this quantity of gas in addition to the demand from any other
appliances being served. The table below gives an indication of
limiting gas pipe lengths and the allowance to be made for
fittings. Refer to BS6891 for further information.
The complete installation, including the gas meter, must be
tested for soundness and purged. Refer to BS6891.
9. Domestic Hot Water
9
10. Gas Supply
