Operating Instructions and Installation Instructions

35
Installation - for contractors
13. Troubleshooting
Problem Cause Remedy
The appliance will not
start despite the DHW
valve being fully open.
The aerator in the tap
is scaled up or dirty.
Clean and/or descale
the aerator or replace
the special aerator.
The sieve in the cold
water line is blocked.
Clean the sieve after
shutting off the cold
water inlet line.
The heater is faulty. Check the resistance
of the heating system
and replace the appli-
ance if required.
The safety pressure
limiter has responded.
Remedy the cause of
the fault. Isolate the
appliance from the
power supply and de-
pressurise the water
line. Activate the safe-
ty pressure limiter.
Activating the safety pressure limiter
1
2
D0000039769
1 1-pole safety pressure limiter MTD 440 / MTD 570
2 2-pole safety pressure limiter MTD 350 / MTD 650