Wolf DHW Series Installation Instructions Manual page 7

Expansion vessels
Sizing of the safety devices
Pressure reducer
Disposal
Thermal insulation
Venting
Drain outlet
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3. Technical information
All expansion vessels must be fitted so that they can be isolated from the
heating system.
Shut-off systems must be sufficiently secured against unintentional closing
(e.g. by means of a cap valve with wire and seal).
Diaphragm expansion vessels must comply with EN 13831.
Expansion vessels must be installed in frost-free rooms or protected against
freezing. Expansion vessels must be designed to DIN EN 12828.
Safety valve (SV), heating water side
Only one individually tested SV may be used. The response pressure must be
suitable for all system components and may not exceed 3 bar.
Exceeding the permissible operating pressure may result in
leaks and could destroy the cylinder.
The SV is designed to DIN EN 12828, DIN 4753 and DIN1988. For this, a
heating output of 1.5 kW for each collector is assumed.
Total heating output
(boiler + collector)
50 kW
100 kW
200 kW
350 kW
The discharge pipe must have a diameter at least equal to the outlet cross-
section of the safety valve, it must not have more than 2 elbows and must be
no more than 2 m long. If it is absolutely necessary to have 3 elbows or a pipe
length of up to 4 m, the nominal diameter of the entire discharge pipe must be
implemented one nominal diameter size larger. More than 3 elbows and a pipe
length above 4 m are not permitted. The discharge pipe must be installed with
a fall. The drain pipe downstream of the tundish must have a diameter at least
twice as big as the valve inlet diameter. Place a sign close to the safety valve
discharge pipe with the following inscription:
"For safety reasons, water is discharged from the discharge pipe
Please note
during heating. Do not close off the discharge pipe".
The installation of a pressure reducing valve is recommended. The permissible
operating pressure of the DHW cylinder is 10 bar on the DHW side. If the supply
network is operated at a higher pressure, a pressure reducer must be installed.
Exceeding the permissible operating pressure may result in leaks and
could destroy the cylinder.
To reduce flow noise inside buildings, the line pressure should be set to approx.
3.5 bar.
Ensure that the cylinder's packaging, and that of any accessories used, is
disposed of correctly. Packaging is collected by our certified disposal partners.
Do not bring fire, solder flames or oxy-acetylene torches into the
vicinity of the insulation.
Please note: Risk of fire.
The cylinders are equipped with a 1" or 1¼" socket in the top centre for the
purpose of venting.
The floor-standing DHW cylinder / buffer cylinder must be installed to enable
it to be drained as fully as possible.
Please note: When draining the system, hot water may escape and
cause injury, in particular scalding.
Nominal diameter
DN 15
DN 20
DN 25
DN 32
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