4
3
2
1
0
General
All domestic hot water circuits, connections, fittings must be
in accordance with the relevant standards and water supply
regulations.
The boilers are suitable for connection to most types of
domestic appliances.
When connecting to suitable showers, ensure that:
a) The cold water inlet to the boiler is fitted with an
approved anti-vacuum or siphon non-return valve.
b) Hot and cold water supplies to the shower are of equal
pressure.
5.1 Water Pressure
This boiler will operate satisfactorily at low water inlet
pressure, however for optimum performance it is
recommended that 22mm feed pipe is used with an inlet
pressure, at the appliance, of 2 bar.
NOTE: Higher pressure can be tolerated as the boiler is
fitted with a pressure reducing valve set at 3.5 bar.
5.2 Expansion Vessel
The boiler has an integral expansion vessel with a capacity of
12 litres (2.6 gallons), with a charge pressure of 3 bar.
NOTE: The expansion vessel volume depends on the total
water system volume and the initial system design pressure.
Guidance on vessel sizing is also given in the current issue of
BS5449 and BS7074 Part 1, for IE refer to the current edition
of I.S.813 "Domestic Gas Installations".
5.3 Draining Point
A draining point is provided at the bottom of the hot water
storage tank located next to the condensate drain, see
diagram 5.1.
4 Heating System
automatic bypass - closed
automatic bypass - factory setting
automatic bypass - open
0
200
400
600
5 Domestic Hot Water
pump speed 1
800
1000
1200
Volumeflow (Litres/hr)
5.4 Safety Valves
The safety valves are factory fitted and are an integral part
of this boiler and they must not be adjusted or used for any
other purpose.
NOTE:
The pipe from the safety discharge valve must not
discharge above an entrance, window or any type of public
access area.
CONDENSE TRAP
AND
SIPHONIC DRAIN
DRAIN
POINT
14
pump speed 2
1400
1600
1800
Diagram 4.2
SCREW
Diagram 5.1
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