Glow-worm Ultrapower sxi Range - Manual (Page 13)

13
4 Heating System
General
The boiler is for use only with sealed central heating systems.
The digital readout on the controls fascia indicates the system
pressure when there is no demand.
The circulation pump is integral with the boiler.
4.1 Safety Valves
The safety valves are factory fitted and are an integral part
of the boiler and 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.
4.2 Expansion Vessel
The boiler has an integral expansion vessel with a capacity of
10 litres (2.2 gallons), with a charge pressure of 0.75bar.
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”.
4.3 Flow Rate
If it is necessary to alter the flow rate, the system can be fitted
with a lockable balancing valve in the main flow or return
pipes shown as valve “A” in diagram 4.1.
The flow rate through the boiler must not be allowed to fall
below that given in section 1 - Specification table.
4.4 Bypass
The boiler is fitted with an automatic adjustable bypass.
Diagram 4.2 shows the pump head remaining for the heating
system depending on the bypass setting and the speed
setting of the pump, see section 12 Commissioning.
4.5 Filling the Sealed System
NOTE: The water pressure at the boiler must be at least
0.7bar to enable filling the boiler to a minimum pressure
through the integral filling device, see diagrams 4.1 and 12.2.
4.6 Water Treatment
In the case of an existing system, it is ESSENTIAL that prior
to installing the new boiler the system is thoroughly flushed.
For optimum performance after installation of a new system,
the boiler and its associated central heating system should
also be flushed. Flushing should be carried out in accordance
with BS7593: 2006 using a cleanser such as Sentinel X300
or X400, Fernox Restorer or Salamander corrosion guard
cleaner.
For long-term corrosion protection, after flushing, an inhibitor
suitable for stainless steel exchangers should be used, refer
to the current issue of BS 5449 and BS 7593 on the use of
inhibitors in central heating systems. Examples are Sentinel
X100 Fernox Protector or Salamander corrosion guard
inhibitor.
Diagram 4.1
13352
4.7 ‘Hard’ Water Areas
The temperatures within the heat exchanger are limited by
the boiler control system to minimise scale formation within
the hot water pipework. However, in areas where the water is
‘hard’ (i.e. more than 200mg/litre), it is recommended that the
hot water setting is reduced and that a scale reducer is fitted,
refer to the manufacturer’s instructions or consult the local
water company for additional advice.