8
User Instructions
7 DISPLAY FUNCTIONS - NORMAL OPERATION MODE
Note:
The temperatures shown below are for illustration purposes only.
The measured temperatures will be shown on the HIU.
HOT WATER
PREHEAT
OFF
00
HOT WATER
PREHEAT
OFF
- -
Summer Mode, DHW enabled and no heat demand:
HIU ‘Off’ Mode:
6 TROUBLESHOOTING
No Hot Water
No Central Heating
No Hot Water or
Central Heating
Check the mains
power is turned
on and if a CCV is
installed the HIU has
credit.
Check the mains
power is turned
on and if a CCV is
installed the HIU has
credit.
Check the mains
power is turned
on and if a CCV is
installed the HIU has
credit.
Is DHW
enabled on the
user interface?
Is CH enabled
on the user
interface?
Does the HIU
have a display
showing on
the front
control panel?
Enable DHW
as described
in section 2.
Enable CH as
described in
section 2.
See HIU ‘Display
Functions’
section.
Is cold water coming
out of the hot tap
when turned on?
Check the
programmer
(internal or external
to the HIU) is in an
‘ON’ position and
the room thermostat
is turned up. Check
the time settings on
the programmer are
correct.
See HIU ‘Display
Functions - Fault
messages’ section.
Is heating
functional?
Contact a registered
engineer or the
person responsible
for managing your
water supply.
Contact a registered
engineer or the
person responsible
for managing your
water supply.
Contact a registered
engineer or the
person responsible
for managing your
water supply.
NO
NO
YES
YES
YES
NO
NO
NO
NO
YES
CCV
= Credit Control Valve
