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5 Water Systems - General
5.1 General
This boiler is designed to provide central heating from a fully
pumped open vented or sealed water system and domestic
hot water using a fully indirect cylinder.
An options board accessory is available to link the internal
programmer with a Honeywell S or Y plan system.
5.2 Draining Points
Draining taps must be provided at all low points of the
system, which will allow the entire system to be drained.
Draining taps shall be to the current issue of BS2879.
5.3 Pump
The pump should be fitted on the flow pipe from the boiler
and have isolating valves each side.
A variable duty pump should be set to give a temperature
difference of no greater than 20
0
C between the flow and
return, with the thermostat set at “MAX”, which is about
80
0
C, to give a flow rate as given in the table.
See chart for pressure loss of the boiler, diagram 5.1.
High resistance microbore systems may require a higher duty
pump.
5.4 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 5.3. The flow
rate through the boiler must not be allowed to fall below that
given in diagram 5.1.
5.5 Bypass
A system bypass will be required fitted at least 1.5 metres
away from the boiler, refer to the current issue of the central
heating system specifications (CHeSS).
5.6 Water Treatment
Existing system- It is ESSENTIAL that prior to installing the
new boiler the system is thoroughly flushed.
New system- For optimum performance after installation,
the boiler and its associated central heating system should
also be flushed.
Flushing should be carried out in accordance with BS7593:
1992 using a cleanser such as Sentinel X300 or X400, Fernox
Restorer or Salamander corrosion guard cleaner.
IMPORTANT: Ensure all cleanser is removed from the whole
system before adding an inhibitor.
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.
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