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3
Installation
B Always turn off the gas cock before car-
rying out any work on components
which carry gas.
Fixing of the appliance, gas and flue con-
i
nections, commissioning of the system
and electrical connections may only be
carried out by competent persons author-
ised by CORGI.
3.1
Important remarks
B Appliance is prepared to be installed in fully pumped
sealed and open vent central heating systems.
B To avoid gas formation in the system, galvanised
radiators or pipes must not be used.
B If a room thermostat is used: do not fit a thermostatic
radiator valve on the radiator in the primary room.
B Add a suitable anti-freeze fluid compatible with alu-
minium to the water in the central heating system.
Suitable products are available from Betz-Dearborn
Tel.: 0151 4209563 and Fernox Tel.: 01799
550811. All system cleaners must be removed
before adding any inhibitor.
B In our experience, the addition of sealing agents to
the water in the central heating system can cause
problems (deposits in the heat exchanger). For that
reason we advise against their use.
3.2
System
The system must comply with the requirements of
BS 6798 and BS 5449.
General
The appliance is only suitable for connection to indirect
fully pumped sealed and open-vent systems. The mini-
mum static head is 1.0 m and the maximum is 30m.
The controls must be wired to ensure that the boiler
does not cycle when the electronically controlled zone
valves are closed.
Note 1: An automatic by-pass is required if the controls
i.e. 2-port valves, can result in the closure of the CH and
DHW circuits when the boiler is hot. If mechanically
operated thermostatically controlled valves are fitted on
all radiators then an automatic by-pass located at least
2m from the boiler is required.
Note 2: A by-pass is generally unnecessary on a sys-
tem using a 3-way diverter valve as one port will be
open to flow at all times. However if TRV's are used
throughout then an automatic by-pass may be neces-
sary. Refer to the current Building Regulations or the
Good Practise Guide 302 which lists all the above
requirements.
Plastic pipes must not be directly connected to the
appliance. A copper to plastic transition piece should
be positioned a minimum of 600mm from the appliance.
6 720 611 137 GB (03.02)
Some plastice pipes are permeable to oxygen and must
be avoided. a pipe with a polymer barrier should be
used.
Sealed System
A sealed system must include an expansion vessel,
pressure gauge and pressure relief valve set operate at
3bar - these are available as proprietary kits. The expan-
sion vessel and fittings must be connected at the neu-
tral point of the system on the entry to the pump. A
pump and diverter valves are also required as appropri-
ate to the system. Refer to Fig. 5, 6, 7. The sealed sys-
tem must be filled through a WRAS approved filling kit.
Refer to Fig. 8. For system wiring please refer to Fig. 12
and the controls manufacturers details.
The appliance must not be operated without the system
being full of water and correcetly pressurised.
All connections in the system must withstand a pres-
sure of up to 3 bar. The system and appliance must be
properly vented. Repeated venting loses water from the
system and usually indicates that there is a leak. A drain
cock to BS 2879 must be fitted to the lowest point of
the system.
No galvanised radiators or pipes must be used.
If any system water treatment is required then only
products suitable for use with aluminium shall be used
i.e. Fernox Super Concentrate or Sentinel X100, in
accordance with the manufacturers instructions. The
use of any other substances will invalidate the guaran-
tee. The pH value of the system water must be less than
8 or the appliance guarantee will be invalidated.
Important: Check that no dirt is left in the water pipe-
work as this could damage the appliance. Thoroughly
flush the heating system and the mains water supply
before fitting the appliance to the wall in accordance
with the recommendations of BS 7593.
Domestic Hot Water
The appliance is NOT suitable for direct water
supply.
Do not connect to a direct cylinder.
The appliance can be connected to any indirect cylin-
der i.e unvented or thermal store, and all the benefits of
a "dry loft" can be realised. For more information con-
tact Worcester Heat Systems Helpline 08705 266241.
Note: Indirect coil type or a direct cylinders with an
immersion calorifier that is suitable for a pressure of
0.35 bar above the setting of the pressure relief valve
may be used. Single feed indirect cylinders are
NOT suitable for sealed systems. Any connection to
the mains water supply must conform to the relevant
Building and Water Regulations and be approved by
the local water company.
Installation
11
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