‐
CW
521/531
24
Err23
Boiler
does
not
heat
up
as
expected
The
problem
might
occur
because
water
is
continually
entering
the
tank
(the
causes
are
as
for
Err5
–
see
above)
If
it
persists,
check
in
this
order:
‐
damaged
boiler
heating
element
‐
contactor
failure,
‐
boiler
safety
thermostat
failure,
‐
boiler
temperature
probe
faulty
or
incorrectly
positioned
‐
motherboard
relay
failure,
Important:
if
the
boiler
heating
element
is
damaged,
this
might
be
due
to
operation
with
no
water
in
the
boiler
‐
the
pressure
switch
is
indicating
full
even
with
the
boiler
empty:
check
and
if
necessary
replace
the
boiler
air
trap
and/or
the
relative
pressure
switch:
the
problem
is
generally
preceded
by
“boiler
overheating
E28”
Err24
Boiler
temperature
probe
malfunction
boiler
temperature
probe
disconnected
or
not
working
Err25
Boiler
water
filling
malfunction
The
boiler
does
not
fill
within
the
allowed
time:
check
water
intake
tap,
dynamic
pressure
in
intake
system,
cleaning
of
water
intake
filter,
possible
damage
to
water
intake
hose
Or
check
in
this
order:
‐
boiler
pressure
switch
has
failed
(continuous
empty
reading)
‐
pipe
leaking/disconnected
(water
entering
pipe)
Err26
Boiler
emptying
malfunction
‐
check
that
rinsing
spray
arm
nozzles
are
clean
‐
boiler
pressure
switch
has
failed
(continuous
full
reading)
‐
pipe
leaking/disconnected
(water
entering
pipe)
‐
rinsing
pump
not
working
Err27
Boiler
emptying
malfunction
–
with
tank
full
Boiler
pressure
switch
has
failed
(continuous
full
reading)
Err28
Boiler
heating
malfunction
(overheating)
First
check:
‐
boiler
pressure
switch
has
failed
(continuous
full
reading)
‐
pipe
leaking/disconnected:
water
entering
pipe
connected
to
air
trap,
pressure
switch
continues
to
give
full
reading
even
with
boiler
empty,
heating
element
operating
dry
Or:
‐
circuit
board
relay
failure,
or
‐
contactor
failure
