Viessmann Vitolig
200 Technical Manual page 57

5 Vitolig 100
5.5 Water connection
Safety equipment acc. to DIN 4751 2
DIN 4751 2 requires the following safety
equipment:
General design notes
H The rated output must not exceed the
heat demand. Solid fuel should burn
with a flame even at a reduced boiler
output. If a minimum heat consumption
of 50 % of the rated output cannot be
guaranteed, provide an adequately
sized heating water buffer storage unit
with 25 litres/kW boiler output.
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H A sealed expansion vessel
H A safety valve at the highest point of
the boiler or a pipe connected with the
boiler.
The pipework between the boiler and
the safety valve must not be able to be
shut off. Pumps, fittings or restrictions
must not be present in this pipework.
The blow−off line should be constructed
so as to prevent the possibility of
increases in pressure.
Any expelled heating water must be
able to be drained off safely. Arrange
the outlet of the blow−off line so that
any water expelled from the safety
valve can be safely observed and
drained off.
H A combustion control unit, a
thermometer and a pressure gauge
H An automatic device for heat disposal,
which prevents the maximum
permissible operating temperature to
be exceeded. To affect this, connect a
thermostatic drain valve (available as
accessory) to the integral heat
exchanger.
H All systems require a return
temperature raising facility and a
weather−compensated control unit with
three−way mixer.
H Connect the integral minimum
temperature regulator to prevent
condensation inside the boiler.
H Seal connections which are not
required with blanking plugs.