User manual

8
Fault Possible cause Remedy
tion phase is acceptable)
• Pump switches on after
prolonged standstill without
any noticeable cause
• Legionella protection
feature has become
activated, or self-
calibration feature has
tripped
• System operates properly
- no changes required
• Pump does not start although
hot water is withdrawn from
system
• There is already hot water
in the circuit
• Water in hot-water
storage tank is not or only
slightly heated
• Controller operates
properly. In this situation,
no cause for starting the
pump exists
• Pump switches on only after
greater quantities have been
withdrawn or does not switch
on at all
• Pump switches on frequently
without any noticeable cause
• Flow sensor not properly
attached on flow pipe
• Insufficient heat contact
between flow sensor and
pipe
• Draught on sensor
• Sensor has not been fitted
to pipe but to large fittings
which heat up only slowly
• Sensor located too far
away from hot-water
• Properly and very
carefully position and
fasten flow sensor (see
installation instructions)
• Provide sensor together
with pipe with heat
insulation
• Select small wall
diameters for fastening