SECTION 7
-
The HIU Controller first power up and set up
Page 16
SECTION 10
-
Fault and Error Codes / Fault finding guide
06/21 E&OE
Diagnostics
-
Fault code definitions.
When a fault occurs the relevant code will be displayed on the controller screen.
Fault codes inform that the controller has diagnosed a fault in one of the HIU
’
s components.
code
Cause
Effect
Remedy
F0
DHW temperature sensor is short circuit or
broken circuit, or disconnected.
The HIU will not operate in DHW demand.
It will still operate in heating demand mode.
Check that the sensor cable plug connection is
good, and if OK then check the connection inside
the controller. If this doesn
’
t clear the F0 code,
then replace the sensor.
The F0 will clear and return to normal operation.
F1
Primary flow temperature sensor is short
circuit or broken circuit, or disconnected.
The HIU will not operate in DHW or heating
demand.
Without information of the primary temperature
in, the controller can not function.
Check that the sensor cable plug connection is
good, and if OK then check the connection inside
the controller. If this doesn
’
t clear the F1 code,
then replace the sensor.
The F1 will clear and return to normal operation.
F2
DHW storage tank temperature sensor is
short circuit or broken circuit, or
disconnected.
The controller disconnects the control of a n
optional hot water cylinder and all its parameters.
Check that the sensor cable plug connection is
good, and if OK then check the connection inside
the controller. If this doesn
’
t clear the F2 code,
then replace the sensor.
The F2 will clear and return to normal operation.
F3
Heating flow temperature sensor is short
circuit or broken circuit, or disconnected.
The HIU will not operate in Heating mode. It will
still operate in hot water demand mode.
Check that the sensor cable plug connection is
good, and if OK then check the connection inside
the controller. If this doesn
’
t clear the F3 code,
then replace the sensor.
The F3 will clear and return to normal operation.
F4
Primary return temperature sensor is short
circuit or broken circuit, or disconnected.
The HIU
‘
keep warm
’
function is disabled as this
sensor controls the DHW PHE temperature during
periods of non
-
use. Also efficiency is reduced as
there is no control of the primary return
temperature
DHW and Heating are both still operational.
Check that the sensor cable plug connection is
good, and if OK then check the connection inside
the controller. If this doesn
’
t clear the F4 code,
then replace the sensor.
The F4 will clear and return to normal operation.
F5
Heating return temperature sensor is short
circuit or broken circuit, or disconnected.
The HIU
‘
heating optimisation
’
function is disabled
as this sensor controls the heating return
temperature . DHW and Heating are both still
operational.
Check that the sensor cable plug connection is
good, and if OK then check the connection inside
the controller. If this doesn
’
t clear the F5 code,
then replace the sensor.
The F5 will clear and return to normal operation.
F6
It is a notification that unexpected
fluctuations in the return temperature have
been monitored during hot water
production. Probable cause is the network
supply to the HIU.
The F6 error code is a notification that this is
unusual. F6 will reset back to normal operation
after 60 seconds.
Check the network supply temperature and flow
and remedy.
If F6 persists, then make a factory reset on the
controller (parameter 00).
This will recalibrate the PICV actuator.
Check DHW sensor is in the correct position.
Check with a manual operation of the PICV.
Set this on parameter 91.
If not working, replace the PICV actuator as a last
resort.
F7
Either the pressure in the heating system is
too low or the pressure switch is faulty.
The HIU will not operate in heating mode. It will
still operate in hot water mode.
Check the system pressure on the gauge on the
HIU. The pressure switch will cut out at 0.15 bar.
Refill system to 1.2 bar.
Resets normal operation after 30 seconds.
If low pressure is not the issue, replace the
pressure switch.
F8
The controller is recognising from the feed-
back from the electrical connection that the
rotation of the pump is not what it is
expected to be.
Depending on the issue, it
’
s most likely that heating
will not be available.
Check wiring connections to the pump. Check
pump for red LED lights signifying a fault.
Check PWM is not set as ON in parameter 24.
Setting must be 00 as factory set.
Only consider replacing the pump head once all
else has been checked
Check water quality which is usually the cause of
a premature pump failure
