8
WARNING
Failure to provide adequate pressure relief
will invalidate any guarantee and lead to a
dangerous installation.
`
Expansion can take place within the cold water
supply provided that both :
•
Backflow in the main is not prevented by any
stop valve with loose jumper, check valve,
pressure reducing valve or similar, and
• Hot water expansion does not enter a branch
to a cold water outlet (see Figure 02 for
expansion pipe lengths).
Both the above conditions must be met.
Additionally expansion within the cold water
supply will not be possible if the static supply
pressure exceeds 0.41 MPa (4.1bar).
`
If any of the conditions in above cannot be met,
expansion must be accommodated using an
Expansion Vessel. To ensure all expansion takes
place in the vessel a Check Valve must also
be fitted together with a Pressure (expansion)
Relief Valve (see Figure 03). Use Accessory
Pack U2 code no. 95 970 351.
`
If the static supply pressure exceeds 0.41 MPa
(4.1 bar) a Pressure Reducing Valve must be
fitted to the cold main supply. If a Pressure
Reducing Valve is used, an Expansion Vessel
must also be used (see Figure 04). Use
Accessory Packs U1 and U2 Code No.’s 95 970
352 and 95 970 351.
Discharge
`
The discharge outlet from the Pressure
(expansion) Relief Valve and the Temperature/
Pressure relief Valve must be connected to
a discharge pipe. It is recommended that the
tundish supplied be installed in the discharge
pipe to give a visible indication that the valves
are operating.
`
The discharge pipe must fall continuously from
the valve outlets and be unobstructed, and in a
frost-free environment.
`
The pipe from the valves to the tundish should
be 15mm o/dia minimum. From the tundish to
the point of discharge the pipe should be 22mm
o/dia minimum and have a resistance to flow
equivalent to 9 metres of straight pipe. Long
discharge pipe runs should have an increased
internal diameter.
`
The water may drip from the discharge pipe of
6. Installation
6.1 General
After reading the previous sections in this booklet
and choosing a good location for the product please
install, paying attention to the following hydraulic,
electrical and commissioning sections.
6.2 Water connections
WARNING
`
Under no circumstances should
the factory fitted temperature/
pressure relief valve be removed
other than a competent person. To
do so will invalidate any guarantee
or claim.
`
No control or safety valve should
be tampered with or used for any
other purpose.
`
The discharge pipe should not
be blocked or used for any other
purpose.
`
The tundish should not be
located adjacent to any electrical
components.
Refer to the Installation schematic (figure 4-6, page
6) to determine which valves and accessories are
required.
Plumb in the valves in the sequence shown in the
relevant figures 4-6, page 6.
`
The water connections are 15mm diameter
copper tubes suitable for compression fittings.
Do not use solder joints as this will damage
the heater and may prevent servicing under
warranty.
`
The INLET is marked BLUE, the OUTLET is
marked RED. The WRAS listed isolating valve
(supplied) must be fitted on the cold water
supply to the product. Several hot outlets can
be served.
`
Plumbers Paste must not be used as it can
impair the operation of the valves.
`
The product MUST be fitted with a Pressure
Relief Valve. The factory fitted Temperature/
Pressure Relief Valve can fulfil this function.
