Additional Requirements When Installing Boilers For Lpg Operation In Rooms Below Ground Level; Flue Gas Monitoring Device; Low Water Indicator; System Water Quality - Viessmann VITOGAS Technical Manual

Design information
5.8 Additional requirements when installing boilers for LPG operation in rooms below
ground level
According to TRF 1996 Vol. 2 – valid as of 1 September 1997 – an
external safety solenoid valve is no longer required when installing the
boiler below ground level.

5.9 Flue gas monitoring device

The EC Gas Appliances Directive specifies the installation of a flue gas
monitoring device for gas boilers up to 50 kW, if the installation room
is not sealed against other rooms of the accommodation or utility area
and is not provided with adequate ventilation.
This does not apply if the installation room is separated from other
rooms through thick walls and tightly fitting, self-closing doors or if it is
adequately ventilated according to the "ventilation requirements"
specified by the TRGI [Germany or by local ventilation regulations].

5.10 Low water indicator

According to the EN 12828, special low water level protection can be
omitted for boilers up to 300 kW, as long as heating can be reliably
prevented when the water level is too low.

5.11 System water quality

For boilers with a rated output in excess of 50 kW, soften the water in
accordance with VDI 2035-1 under the following circumstances:
■ If the total amount of alkaline earths is in excess of 2.0 mol/m³.
■ If the volume of fill and top-up water exceeds three times the water
content of the heat system during its service life.
■ If the specific system volume is in excess of 20 l/kW.
Control units
6.1 Overview of control unit types

Vitotronic 100, type KC3

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VIESMANN
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(cont.)
However, the high safety standard derived from the use of an external
safety solenoid valve has proved to be valuable. We therefore recom-
mend the continued installation of an external safety solenoid valve
when installing the boiler below ground level.
The flue gas monitoring device can also, e.g. on request of the building
owner, be retrofitted in non-living spaces after the installation of the
boiler.
Viessmann Vitogas are equipped with type-tested thermostats and
high limit safety cut-outs. Tests have verified that the burner will be
automatically switched OFF in the event of water shortage due to a
leak in the heating system and simultaneous burner operation, before
the boiler or the flue system reach unacceptably high temperatures.
For further details regarding the water quality requirements, see the
technical guide Vitogas from 72 kW.
Electro-mechanical boiler control unit:
■ For one heating circuit without mixer
■ For a single stage burner
According to the EnEV [Germany], a weather-compensated or room
temperature-dependent control unit with time program for reduced
mode must be installed downstream.
VITOGAS