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6. Secondary circuit installation.
6.1.
-
Connections
. Secondary circuit
connections
MUST
be made to the cylinder in accordance
with Fig 1.and Fig 5. A drain cock (not supplied) should be fitted in the position shown in Fig 5
to facilitate draining of the cylinder.
6.2
. -
Cold water supply –
Where possible, for best results, the cylinder should be fed by an
uninterrupted 22mm supply pipe into the pressure reducing valve (PRV) with a supply pressure
of between 3 and 12 bar maximum. In the UK supply pressures this high are not always
available. However the system will still work satisfactorily with pressures below this. The
cylinder should not be used on any system with a supply pressure below 1.5 bar and a flow rate
of less than 20 litres per minute.
6.3.
-
Temperature and pressure relief valve
– The temperature and pressure relief valve
(T/PV) is supplied factory fitted to the cylinder. This connection
MUST NOT
serve any other
purpose nor have any other valve or obstruction fitted between it and the cylinder. The valve is
pre calibrated to lift at 7 bar or 90 degrees centigrade and any attempt to adjust it will invalidate
the warranty.
6.4.
-
Expansion vessel –
A 20 litre expansion vessel with a pre-charge pressure of 3 bar is fitted
at the factory to all cylinders with storage volumes up to and including 200 litres. For cylinders
of 250 and 300 litres capacity, a separate 24-litre expansion vessel is supplied which MUST be
connected into the cold water supply side between the expansion relief valve and the cylinder.
The expansion vessel MUST be positioned with the entry point at the bottom.
IMPORTANT:
Regular checks must be carried out to ensure that the expansion vessel is
correctly pressurised to 3 bar at all times.
6.5.
-
Pressure reducing valve
– Taking due account of the directional arrow, fit the pressure
reducing valve (PRV) in accordance with Fig 5. This can be connected to a supply pressure of
between 1.5 and 12 bar maximum.
6.6.
-
Expansion relief valve –
Fit the expansion relief valve (ERV) in accordance with Fig 5.
This valve has been pre-set to lift at 6 bar. No other valve should be fitted between the expansion
relief valve and the cylinder.
6.7.
-
Check valve –
Taking due account
of the directional arrow
,
fit the check valve (CV) in
accordance with Fig 5.
6.8.
-
Secondary circulation –
If the installation requires a secondary circulation circuit, a
15mm return leg, which incorporates a check valve should be connected via the cold feed using a
22 x 22 x 15 swept tee.
IMPORTANT: If a secondary circulation circuit is installed then a larger expansion vessel may
be required to handle the increase in volume.
6.9.- Tundish –
The tundish must not be positioned above or in close proximity of any electrical
current carrying devices or wiring.
