IS 339 ECN 3607
Page 9 of 11
The control panel displays information that can help with fault diagnosis. Before
calling for service, draw off a litre of water, clear the fault code by pressing the
Fn
button and turn the boiler off and on again at the supply. If the fault persists, call
service for advice.
Message displayed
Possible causes
Corrective action
FILTER DESCALE
CAUTION
SEE MANUAL
STANDBY CLEAR
Scale on level sensors
Boiler overfilling
Descale
Check water inlet valve
FILTER NO WATER
FAULT
SEE MANUAL
STANDBY CLEAR
Water turned off
Inlet hose kinked or
blocked
Water pressure too high or
low
Drain valve open
Check water supply and
drain valve
Call service if fault
persists
FILTER NOT HEATING
FAULT
SEE MANUAL
STANDBY CLEAR
Boil dry/overheat protector
tripped
Temperature sensor fault
Element failed
PCB fault
Faulty or loose connection
Check connections
Call service if fault
persists
FILTER THERMISTOR
FAULT
SEE MANUAL
STANDBY CLEAR
Temperature sensor fault
Call service
FAULT FINDING