SECTION 7
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The HIU Controller first power up and set up
Page 18
SECTION 10
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Fault and Error Codes / Fault finding Guide
Performance issues where no fault code is displayed
Ref
REPORTED ISSUES
Trouble Shooting Checklist
1
The water from the hot taps is COLD.
•
Is there power to the HIU?
•
Is the unit going into hot water mode?
•
Possible blockages –
if there is heat coming into the HIU from the communal
heating system, follow the path through the Strainer, PICV, Diverter ?
•
Plate Heat Exchanger blockage, possibly scale. If suspected take the necessary
steps to remove and clean (Fig 8B in the Section Maintenance).
•
No flow or insufficient flow through the flow sensor or flow sensor not
working?
Once blockages are cleared, then reconnect the unit, and follow the
commissioning instructions.
2
There is NO WATER at the Hot Taps.
•
Is there water at the cold taps? If not, check the mains stop tap. If it is found
to be closed, open it and check the fault is resolved. Check piping.
•
Are the HIU isolation valves open or closed?
If not check for blockages on the cold water supply pipe. Check all filters and clean
if blocked.
3
Insufficient Hot Water at the taps, but no
error codes on the HIU Controller screen.
Is it a flow or temperature problem?
Is the primary flow sufficient?
Low primary flow caused poor or no DHW
performance!
If all checks prove the HIU is working correctly,
•
Is there a bypass fitted on the primary before the HIU, and it has been left
open? CLOSE the valve, the HIU will now work as designed.
•
Is the TMV set at the correct temperature? Has it been tampered with or
reset in error? Set to 57C.
•
Is there enough FLOW at the HIU? If the supply pumps have not been de-
signed to the required flow of the HIU, then DHWS will not be sufficient.
•
Similar for pipework, if not sized correctly, the HIU will not be able to deliver
to its designed output.
4
•
No Room Heating
•
Radiators are COLD.
•
Under Floor Heating is installed Floor is
COLD.
•
No Room Heating or Hot Water.
•
Check the ambient temperature. Is the reason that the room thermostat
setting is too low to switch on the heating?
•
System low pressure. Has the safety valve discharged? Check system pressure
and top up if necessary.
•
Air blockage in the radiators.
•
Check the Circulating Pump (see LED lights on the pump which can warn of a
problem or a fault). Is the pump fully operational?
•
Is the controller set up correctly? See Installer settings.
•
Is the Room thermostat wired correctly? Is it working?
•
Check that the communal heating is supplying heat to the unit.
•
Check then that the isolation valves to the unit are open.
•
Is the Bypass Valve open on the valve above the HIIU?
5
The Control mode seems to be frozen in
either Heating or Hot water modes, and will
not change even regardless of demand or no
demand.
•
A PCB in the Controller is damaged. Look for the cause first before replacing.
Caution! Has a 230v supply has been connected in error to a zero volt
connection, either the T1 / T2 connection for the room stat or on the
connection position for pre
-
payment connection? This should be checked by
a qualified electrician before attempting any repair!
06/21 E&OE
