Nimbus Compact M NET R32 Installation Manual UK

Hydraulic connections
4.2 Installation of the Hydraulic KIT
4.2.1 Safety inlet assembly
It must be installed on the domestic hot water inlet before the
water enters the tank. It consists of a pressure reducing valve,
an expansion relief valve and a check valve, and connects the
system to the expansion vessel.
4.2.4 Safety device connection
T&P relief valve
The factory-fitted temperature and pressure relief valve on top
of the cylinder is a safety device that backs up the thermostatic
control device(s) and non self-resetting energy cut-out(s). It
works by sensing an excess water temperature or pressure and
discharging the hot water.
General structure
1
2
Possible T&P valve connection
Discharge pipes from the temperature & pressure relief valve
(T&P) and expansion relief valve may be joined together. For
connection to the discharge line of the T&P pressure and relief
valve, use the water connection (male, G ½”) located on the
side of the indoor unit.
7
6
5
4
3
Fig. 47
Safety device assembly information
Safety devices should discharge either directly or by way of a
manifold via a short section of metal pipe (D1) to a tundish. The
diameter of discharge pipe (D1) should be not less than the
nominal outlet size of the safety device, e.g. temperature relief
valve. Where a manifold is used, it should be sized to accept
and discharge the total flow from the discharge pipes connected
to it.
The tundish should be arranged vertically in the same space as
the non-vented hot water storage system, and should be fitted
as close as possible to the safety device, in a lower position,
with no more than 600 mm of pipe between the valve outlet
(T&P) and the tundish. Do not install the tundish near electrical
devices (see Fig. 47).
1 Expansion relief valve (set to 6 bar)
2 Service 3/4” pressure reducing cartridge and line strainer
(set to 3.5 bar)
3 Cold mains water inlet (22 mm)
4 Balanced cold water take-off with non-return valve (22
mm)
5 3/4” BSP connection for expansion vessel
6 To cylinder (22 mm)
7 Expansion relief outlet to tundish (15 mm)
If the Cold Water Balanced Takeoff is not used, a cap shall be
installed.
4.2.2 Exspansion vessel
The expansion vessel must be connected to the dedicated inlet
on the safety inlet assembly.
Check with your local water authority on what type of installation
is acceptable in order to conform to the applicable building
regulations and standards.
4.2.3 Tundish
Installed in the discharge pipe after the valves, it provides an air
break allowing the discharged flow to be safely conducted to
the termination point. The tundish also provides a visible indication
of the discharge and functions as backflow prevention
device. To install it correctly, refer to paragraph Safety device
connection.
Discharges
Any discharge should be visible at the tundish. In addition,
where discharges from safety devices may not be evident, e.g.
houses inhabited by people with impaired vision or mobility,
it may be useful to install a suitable safety device to warn people
when the discharge occurs, e.g. an electronically operated
device.
Connection of the discharge pipe (D2) to the tundish
The discharge pipe (D2) arriving from the tundish should:
– have a vertical pipe section at least 300 mm long below
the tundish before any elbows or bends in the pipework
(see Fig. 47);
– be installed with a continuous fall of at least 1 in 200
thereafter.
Examples of discharge arrangements
The discharge pipe (D2) from the tundish should terminate in
a safe place where there is no risk for people in the vicinity of
the discharge.
Below are some examples of acceptable discharge arrangements:
– to a trapped gully with the end of the pipe below a
fixed grating and above the water seal;
– downward discharges at low level, i.e. up to 100 mm
above external surfaces such as car parks, hard standings,
grassed areas, etc. are acceptable, provided that a
wire cage or similar guard is positioned to prevent contact,
whilst maintaining visibility;
EN / 29