Glow-worm Flexicom hx - Manual (Page 12)

12
0 5 10 15 20 25 30
Flow Rate (litres/min)
24kW
30kW
Pressure Loss (metres)
15kW
35kW
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.
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 o C between the flow and
return, with the thermostat set at “MAX”, which is about 80 o 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 in diagram 5.2. 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 is required and should be fitted at least 1.5
metres away from the boiler, refer to the current issue of the
central heating system specifications (CHeSS).
5.6 Unvented DHW System
Where a storage system will not have a vent to atmosphere
the installation must comply with the building regulations and
the Water Supply (water fittings) Regulations 1999 and water
byelaws 2000, Scotland , see also the current issue of BS5546
and BS6700.
If fitting to an existing system the local authority should be
informed.
General - All domestic hot water circuits, connections, fittings
must be in accordance with the relevant standards and water
supply regulations.
For GB: Guidance G17 to G24 and recommendation R17 to
R24 of the Water Regulations Guide.
For IE: The current edition of I.S.813 “Domestic Gas
Installations”.
Diagram 5.1
14401
5.7 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:
2006 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
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.