Mounting The Burner; Pressure Switch; Fuels - Viessmann Vitocrossal 300 Installation Instructions For Contractors

Making the safety connections
!
Please note
Unsuitable water quality can damage the boiler
shell.
Only fill the boiler with water that complies with
the "Water quality requirements" (see service
instructions).

Mounting the burner

For burner mounting, see separate burner docu-
mentation.
■ Fit the burner plate (in the pack supplied).
■ The circle of burner fixing holes and the blast tube
aperture match the dimensions of many well-known
burner makes.
Rated heating out- from kW
put to kW
Hole circle
7
Blast tube aperture
7
Fixing screws
: The circle of burner fixing holes and the blast
c
tube aperture match the dimensions recommended
by the KRW/VSO.
■ If the actual dimensions do not match, drill the burner
plate to suit.

Pressure switch

Pressure switch
The pressure switch is a safety accessory and is
required for every boiler to EN 303 with pressure-jet
burners to EN 676 (third party burners) for shutting
down the burner in case of flue gas back pressure/
condensate banked up in the boiler/flue system.
The adjustable, interlocking pressure switch is connec-
ted to the control unit safety chain, and to an additional
pressure measuring connector for "combustion cham-
ber pressure". The control unit safety chain is connec-
ted in series to the maximum pressure switch, the min-
imum pressure switch and the high limit safety cut-out.
A setting of approx. 2 mbar above the actual combus-
tion room pressure in full load operation ensures the
burner will shut down used in the event of a fault. The
pressure is measured in full load operation upstream
of the pressure switch.

Fuels

Natural gas and LPG in accordance with DVGW Code
of Practice G 260/I and II or local regulations.
Observe SVGW regulations.
(cont.)
187
314
mm 270
mm 240
M 10
:
c
■ In the case of different dimensions, adjust the cut-out
in the thermal insulation of the boiler door according
to the blast tube diameter.
■ After mounting the burner, seal the annular gap
between the blast tube and the thermal insulation
block with the heat-resistant insulation material sup-
plied.
408
Danger
635
Leaks can result in a risk of poisoning through
330
escaping gas.
290
Prior to commissioning, check the boiler door
M 12
gasket for correct seating and realign, if
required. Otherwise there could be an ingress of
secondary ventilation and condensate might
form on the boiler door; gas could also escape.
Note
The hose for measuring the pressure is also connec-
ted to the combustion chamber sight glass.
"Pressure switch set" installation instructions
31