Viessmann VITOPLEX 100?LS Installation And Service Instructions Manual page 20

Troubleshooting
Diagnostics
(cont.)
Fault/
system characteristics
Water level limiter
switches OFF
20
Cause
The shut−off valve in the
feed water line is closed
No feed water in the
condensate container
The feed water pump or
water level control is
faulty
Severe water level
fluctuations through
excessive alkalinity
Remedy
Open the shut−off valve
Check the mains water
connection
Determine the cause for
the fault on the water
level control in
accordance with the
controller installation
instructions
Drain water from the
boiler and the
condensate container.
If a desalination valve is
fitted, increase the
desalination rate.
Refill with treated water.
Blow−down more
frequently. Check the
water treatment system.