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F
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T FINDING F
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T FINDING F
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T FINDING F
AUL
T FINDING F
AUL
T FINDING
Installation and Servicing
SECTION 4 - FAULT FINDING
4.2 ADDITIONAL FAULT FINDING
Is CH enabled
on the user
interface?
Please refer to
Section 2.1
Enable CH
via the user
interface as
described in
Section 2.1
Are the timer
and room
thermostat
switched on?
Switch
the timer
and room
thermostat on
Are the
radiator valves
open?
Open the
radiator valves
Is there
230Vac at
SL1?
There is not voltage
from the timer/room
stat. Ensure voltage
is supplied to the
HIU
Replace PICV
as shown in
Section 3.24
NO
NO
NO
NO
YES
YES
YES
YES
No CH operation but DHW OK
Is the ‘Tap’
symbol shown
on the display
during a DHW
demand?
Ensure the wiring
between the turbine
& PCB is correct.
Remove DCW
manifold and check
for debris in the
turbine and filter.
Replace turbine if
necessary.
Is there an
air gap in
the primary
circuit?
Purge primary
circuit via the
air vents
Is the PICV
opening?
Check wiring to
PICV and replace
PICV if required
Replace DHW
Plate Heat
Exchanger
NO
YES
YES
No DHW operation but CH OK
YES
NO
NO
Is there
230Vac to the
HIU input? As
shown in 2.9
Replace PCB
Supply power to
the HIU via the
terminal block
shown in
figure
2.9 securely
NO
No Display
YES
