Viessmann Vitomax HS M73 Operating And Service Instructions page 11

Description of selected components in a steam...
Lowest water level (NW electrode/low water level LWL
Level electrode to safeguard against water shortage
Function Operating condition
Self-monitoring low Standard
water indicator com- water level
prising:
2 level electrodes
■
Evaluation devices
■
Too low
water level
Min. boiler water capaci-
ty reached
Tab. 3
Safety valve wP
Function
■ Physical protection of the steam boiler against pres-
sures in excess of the max. permissible operating
pressure PS
Valve response pressure = permissible steam boiler
■
operating pressure
Testing/checks
Operating checks at regular intervals or in accordance with country-
specific regulations
Regular checking by an authorised contractor or test body
Tab. 4
Air vent shut-off valve
Function
Venting the steam boiler during filling
or after a new system start at atmos-
pheric pressure
Tab. 5
Danger
Hot air/steam can cause severe burns.
Discharge hot air/steam safely. Observe safety
regulations.
Steam shut-off valve
wW
Function
Main steam boiler shut-off to the
steam supply
Tab. 6
Operating information
Burner operation enabled.
Safety chain closed.
Electrode is immersed in conducting boiler water. Registers
low resistance.
Electrode is not immersed in conducting boiler water. Regis-
ters a high resistance.
Safety chain and burner operation constantly interrupted.
Re-enable safety chain.
Burner block lifted.
(optional)
wQ
Operation
Open the valve during the
heating process. As soon as
you see steam emerging,
close the valve again.
Operation
Releasing steam or isolating
the steam boiler
(cont.)
qW )
■ Valve discharge rating
≥
boiler)
■ Maximum pressure increase until the SIV opens
completely (at maximum discharge) = PS + 10
Closing pressure is PS - 10
■
Operating information
Vent the lever briefly - do not release the
lever (see manufacturer's operating in-
structions).
Never remove the lead seal.
Operating information
Discharge hot air/steam safely.
Operating information
Open slowly to avoid steam hammer.
Functions
max. steam output (steam
%
%
11