Vaillant 0010044426, Operating Instructions Manual, Page: 46 / 168

46
Installation and maintenance instructions 0020323586_00
Appendix
A
Troubleshooting
Diagnostics in accordance
with the LED display Fault Possible cause Troubleshooting
No LED lights up No domestic hot water
generation The fuse has tripped. Check the circuit breaker (fuse) and,
if required, switch it on.
The PCB is defective Replace the product
The green LED flashes Product does not start The shower head and/or aerator for
the water tap are calcified Descale the shower head and/or
aerator for the water tap, or replace
it
The domestic hot water
flow rate quantity is too
low The product's filter is dirty Clean the filter
No domestic hot water,
while the flow rate quant-
ity is greater than the ini-
tial flow rate The volume flow sensor is defective Replace the product
The green and yellow LEDs
flash (not in every case) The set temperature is
not reached The product has reached its power
limit Reduce the flow rate quantity, install
a flow rate limiter, check the flow
rate limiter
One of the product's phases is de-
fective Check the circuit breaker (fuse) and,
if required, switch it on.
The green LED flashes and
the yellow LED lights up
permanently The set temperature is
not reached The target valuator or the connection
cable is defective. The connection
cable is not connected. Connect the connection cable; if
required, replace the valuator.
The scald protection is activated Deactivate the scald protection
The outlet sensor is defective Ensure that the outlet sensor is con-
nected; if required, replace the outlet
sensor.
No domestic hot water,
while the flow rate quant-
ity is greater than the ini-
tial flow rate The heating system is defective Check the resistance of the heating
system and, if required, replace the
product.
The PCB is defective Replace the product
The green LED flashes and
the red LED flashes quickly No domestic hot water
generation The product is calcified Replace the product
The green LED flashes and
the red LED lights up per-
manently No domestic hot water
generation The safety pressure switch has been
triggered. Open a draw-off valve downstream
of the product for one minute in or-
der to allow the heating system to
cool. Activate the safety pressure
switch by pressing the safety switch
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Electronics safety fault Replace the product
The inlet sensor or the connection
cable is defective. Check the cable connection and, if
required, replace the inlet sensor
Short circuit in the outlet sensor or
connection cable. Check the connection and, if re-
quired, replace the outlet sensor
The PCB is defective Replace the product
The desired temperature
of > 55 °C is not main-
tained The cold water input temperature is
above 55 °C Reduce the product's inlet temperat-
ure
The product switches
itself off The air detection registers air
The domestic hot water generation is
temporarily switched off The product restarts after one minute