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Section 4: Secondary Circuit Installation
4.1 GENERAL
Grant MonoWave indirect HP cylinders are supplied with the
safety devices and components loose in a kit, with the exception
of the Temperature & Pressure (T&P) relief valve which is factory-
fitted. These safety devices and components MUST be fitted to
the cylinder as detailed in the following Sections 4.2 to 4.13. For
a list of these safety devices and components refer to either Table
2-3 or 2-4, as appropriate.
For commissioning and maintenance purposes, it is essential to
fit a service valve (not supplied) in the cold water supply pipe,
immediately before the inlet manifold.
The ½ʺ drain cock (supplied in the kit) must be fitted in the cold
feed to the cylinder to provide a means of draining the unit. Refer
to Figures 2-6 to 2-10 (as appropriate) for a suitable drain cock
position that will enable most of the cylinder to be drained off
when required.
4.2
COLD WATER INLET MANIFOLD
This manifold contains a pressure reducing valve, double check
valve and expansion relief valve with a stainless steel seat.
The pressure reducing valve is factory set to 3 bar. The set
pressure is shown on top of the valve. The maximum inlet
pressure to this valve is 12 bar.
A balanced cold water connection is provided on the inlet
manifold. Refer to Figure 4-1. This should only be used to provide
balanced cold supplies to shower valves and mixer taps. If the
balanced cold water outlet is not required, blank off this port.
4.3 INSTALLATION
1.
Cold water supply pipe to be 22mm nominal size.
2.
Flush supply pipework before connection to remove all flux
and debris prior to fitting the inlet controls.
Failure to do this may result in irreparable damage to the
controls and will invalidate the warranty.
3.
Once the pipework is flushed connect the cold supply to the
Inlet manifold.
The manifold can be installed in any position as long as it is
installed in the correct flow direction. Refer to the arrows on
the side of the body.
Make sure that the head of the expansion relief valve is offset
from the cylinder for ease of access.
4. The expansion relief valve should be either horizontal or
upright - if fitted inverted, debris may be deposited on the
seat and cause fouling of the seat when the valve operates.
Check direction of flow arrows.
5. If the installation requires one, a pressure gauge should be
sourced and fitted on the cold water supply to the cylinder,
between the inlet manifold and the cold water inlet tapping on
the cylinder.
6.
Connect the expansion vessel directly to the ¾” BSPF
connection in the inlet valve manifold body, after removing
the black plastic plug. See Figure 4-1 and Section 4.4.
7. The expansion relief drain pipework must be connected to a
safe visible discharge point via the tundish (supplied in the
unvented hot water safety kit) and the pipework must have a
continuous fall.
8.
Connect the expansion relief valve outlet into the discharge
pipe from the temperature and pressure Relief valve using
a 15mm copper pipe and tee piece (not supplied). Fit the
tundish below this tee piece using a short length of copper
pipe. Refer to Sections 4.9 to 4.13 for further information on
the Tundish and Discharge pipe.
9. The pressure reducing valve has two outlets, the second one
is for a balanced cold water supply, to a shower or a bidet
(over rim type only, ascending spray type requires type AA,
AB or AD air gap).
Major shower manufacturers advise fitting a mini expansion
vessel in the balanced cold supply to accommodate thermal
expansion and prevent tightening of shower controls.
If the dwelling has a shower mixing valve (manual or
thermostatic) or a Bidet (over rim type) use the cold water
supply from the balanced cold water connection on the inlet
manifold for these outlets.
Do not use the balanced cold connection to supply bath taps
as this can reduce the flow of water available to the cylinder.
If the balanced cold water outlet is not required, blank off the
connection.
10. The Benchmark book enclosed with the cylinder should be
completed after commissioning of the system.
11. 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 SECONDARY CIRCUIT INSTALLATION
Figure 4-1:
Cold water inlet manifold
Cold water
supply
Balanced cold
outlet
Cold inlet
to cylinder
Expansion
relief
Expansion
relief valve
Pressure
reducing valve
¾” BSPF expansion
vessel connection.
(Remove black plug
prior to connection)
Circlip
Summary of Contents for HPMONO/IND125
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