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WATER SYSTEMS
1.1 The appliance is suitable for fully pumped open vent & sealed
systems only and the installation must comply with the
requirements of BS 6798 and BS 5449. Fit a drain off cock in
the lowest part of the system. Where the boiler is also to be
used for providing domestic hot water, a double feed indirect
cylinder to BS 1566 Part must be used.
1.2 An adjustable bypass valve must be fitted between the flow
and return and it must be adjusted so that the return
temperature to the boiler is always above 60°C. After setting
this, the bypass should then be fixed. This will increase the
life of the heat exchanger and failure to fit a correctly
adjusted bypass will invalidate the warranty.
1.3 Flush out the system to remove any swarf or residues before
fitting the circulating pump.
2.1 Operation of the system under control of the boiler
thermostat alone does not produce the optimum efficiency.
The heating system should include a control system. This
should comprise of at least a single channel programmer or
thermostatic radiator valves (TRV). In the case of the boiler
being used for central heating and domestic hot water, a 2
channel programmer should be used.
3.1 The appliance is suitable for connection to a sealed system
and the installer needs to fit an expansion vessel of the correct
size, pressure relief valve, pressure gauge, pump and automatic
air vents and provide provision for filling. See diagram 1 for
schematic piping diagram.
1. GENERAL
2. SYSTEM CONTROLS
3. SEALED SYSTEMS
4. EXPANSION VESSEL REQUIREMENTS
5. SYSTEM FILLING
TOP UP
BOTTLE
AIR VENT
PRESSURE GAUGE
SAFETY VALVE
FILL POINT
EXPANSION
VESSEL
PUMP
BYPASS
VALVE
HEATING
CIRCUIT
SEALED SYSTEM PIPING DIAGRAM
1
Vessel Charge & Initial System Pressure
Bar 0.5 1 1.5
psi 7.31 4.5 21.8
To calculate the expansion vessel
required multiply the total system
volume (including 38L for boiler) 0.08 0.11 0.16
by the following factor
Note if the system pressure gauge indicates 2.6 bar or higher
with the appliance at maximum temperature and all radiators
in circulation an additional vessel is required.
Total water content of boiler is 38 litres.
5.1 A sealed system must only be filled by a competent person
using one of the approved methods shown in diagram 2.
The system should incorporate the connections appropriate
to one of these methods. It is recommended that a suitable
inhibitor is added to the system after the final hot flushing.
METHOD OF MAKEUP:
5.2 Water loss from the system should be replaced from a
makeup vessel connected to the system through a non return
valve on the return side of the heating circuit. This vessel
should be higher than the top of the system.
5.3 Alternatively provision can be made by pre-pressurisation of
the system via a temporary hose connection and through a
double check valve (non-return) and stop valve.
2