Thermal Expansion Tank (Not Supplied With The Appliance); Temperature Mixing Device (Not Supplied With The Appliance); Pressure Limiting Valve (Not Supplied With The Appliance); Expansion Control Valve (Not Supplied With The Appliance) - Bosch Compress 3000 DW FOO Installation Instructions Manual

18 | Installation instructions
water heater when operating with both electrical heater and
heat pump and air at 40 °C. The supplied PTR valve complies
with this by having a power capacity of 10kW.
WARNING:
Never block or seal the outlet of the PTR
valve or it's drain for any reason.
The warranty will be void if the relief valve or
other safety devices are tampered with or if
the installation is not in accordance with this
manual.
Connect the outlet of the relief valve to a suitable open drain so
that the discharge water cannot contact any electrical parts,
persons or animals and to eliminate any other possible risks.
A drain line from a relief valve must comply with the
requirements of AS/NZS 3500.4.
WARNING:
To reduce the risk of excessive pressures
and temperatures in this water heater, install
temperature and pressure protective
equipment required by local codes and no
less than a combination temperature and
pressure relief valve certified by a nationally
recognized testing laboratory that maintains
periodic inspection of production of listed
equipment or materials, as meeting the
requirements of AS/NZS 3500.4, AS/NZS
3000 and all local codes and regulatory
authority requirements.
Always use a valve of the same rated pressure and temperature
as the PTR Valve supplied with the unit.
4.4.5 Thermal expansion tank (not supplied with the
appliance)
Thermal expansion is a natural process where heated water
increases its volume. When this water is stored in a tank, this
volume increase will in fact mean a pressure increase. This
pressure increase can result in a dangerous situation. If the
safety settings on the relief valve are reached, then the relief
valve will operate during the heating cycle. Thermal expansion,
if normally reaching the relief valve nominal values, can cause
premature valve failure and contribute to increased
components stress.
Bosch recommends therefore the installation of an expansion
tank in order to relieve this over-pressure, avoiding repeated
relief valve operation.
Please contact a licensed professional, water supplier or
plumbing inspector for more information about this subject.
6 720 808 869 (2014/06)
Table 3 can be used as guideline to help choosing the capacity
of a thermal expansion tank according to the installations mains
pressure and the PTR valve supplied.
Mains water Capacity of the thermal expansion
pressure (bar)
2
3
4
Table 3
4.4.6 Temperature mixing device (not supplied with the
appliance)
WARNING:
This water heater can heat water to
temperatures which can cause scalding.
Bosch recommends the installation of a temperature limiting
device between the water heater and the hot water outlets in a
bathroom or similar usage point, in order to reduce the risk of
scalding.
Additionally, a certified plumber may have the legal obligation
to ensure the water heater installation meets the hot water
delivery requirements listed in AS/NZS 3500.4.
4.4.7 Pressure limiting valve (not supplied with the
appliance)
In installations where the mains water supply pressure exceeds
that specified for this product (listed in chapter 3), an
approved pressure limiting valve is required and must be fitted.
If the water heater is supplied with low pressure water, below
the minimum working pressure specified for this product
(listed in chapter 3), then a pressure pump should be installed
in order to minimize the forming of air traps in the hydraulic
circuit.
4.4.8 Expansion control valve (not supplied with the
appliance)
Local regulations, a saturation index greater than +0.4 or in
corrosive water areas where there are sufficient quantities of
silica dissolved in the water may require the installation of an
expansion control valve (ECV) in the cold water line, being the
last valve installed prior to the water heater.
tank (l)
12
14
18
Compress 3000 DW FOO