Section 4: Secondary Circuit Installation Page 13
10. The cylinder must be registered with Grant UK within 30 days
of installation. Refer to Section 13 for further details on the
Cylinder guarantee.
4.4 SECONDARY CIRCUIT EXPANSION
VESSEL
A 19 litre potable hot water expansion vessel with a pre-charge
pressure of 3.0 bar is supplied tted to the secondary circuit of all
Grant QR integrated indirect heat pump cylinders.
This expansion vessel is connected directly to the cold water inlet
manifold tted to the cold water supply pipework (refer to Figures
2-2 and 4-1).
This expansion vessel is located in a compartment above the hot
water cylinder. Refer to Figure 2-2.
No valve should be tted between the expansion vessel and
cylinder.
The air charge pressure in this expansion vessel must be
regularly checked (e.g. at every service) and topped up as
necessary. The correct air charge pressure for this expansion
vessel is 3.0bar. Refer to Sections 7.1 and 7.4 for further details.
4.5 TEMPERATURE AND PRESSURE
RELIEF VALVE
The temperature and pressure relief valve (T&P Valve) is supplied
factory tted to the cylinder. The T&P valve must not be removed
from the cylinder or tampered with in any way. The valve is pre-set
to lift at 7bar or 90°C and any attempt to adjust it will invalidate the
guarantee.
4.6 HOT WATER SUPPLY
Connect the hot water supply pipe to cylinder connection G (refer
to Figure 3-1). To make this connection, remove one of the 22mm
straight compression couplers from the accessories pack supplied
with the cylinder and make the connection to cylinder connection
G (see Figure 3-1).
4.7 PREVENTION OF SCALDING
Building Regulations Approved Document G (Part G3) requires
that the hot water temperature supplied to a bath should be
limited to a maximum of 48°C by using an in-line blending valve
(not supplied with the cylinder) with a maximum temperature stop.
The length of the supply pipe between the blending valve and the
bath hot water outlet should be kept to a minimum to prevent the
colonisation of waterborne pathogens (e.g. legionella). Refer to
Approved Document G for further details.
4.8 SECONDARY RETURN
All Grant QR integrated indirect heat pump cylinders are tted
with a secondary return connection, which is blanked from factory.
If a secondary return circuit is required it should be connected to
the cylinder as shown in Figure 4-2.
! NOTE !
If a secondary circulation circuit is installed then a larger
expansion vessel may be required to handle the increase
in volume.
Figure 4-2: Secondary return circuit
Balanced cold supply for showers
or bidet only (see Section 4.2)
Secondary
return line
Circulation
pump
Non return
valve
Cold inlet
Balanced cold
supply outlet
.
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