Unit
Malfunction or protection
Error code
in error
Communications error between the hydronic
boards (for cascaded applications)
Hd
IU
Communications error between the main board
HE
IU
and the thermostat expansion board
Eprom EE error on the inverter module board 1. EEprom error; rewrite the data on the EEprom.
HF
EU
H6 displayed 10 times in 2 hours
HH
EU
Low pressure protection in cooling Pe<0.6 oc-
HP
EU
curred 3 times in one hour
L0
Inverter module protection
EU
L1
Protection for low voltage on DC bus
EU
L2
Protection for high voltage on DC bus
EU
L4
MCE error
EU
L5
Zero speed protection
EU
L7
Phase sequence error
EU
Frequency variation of the compressor greater
L8
EU
than 15Hz per second
Working frequency of the compressor different
L9
EU
over 15Hz compared to target frequency.
Low pressure switch protection
P0
EU
P1
High pressure switch intervention
EU
Compressor electrical current absorption great-
P3
EU
er than maximum limit allowed
Compressor drain temperature (Tp) greater
P4
EU
than the maximum limit allowed
Temperature difference between Tw_out and
Tw_in too high
P5
IU
P6
Inverter module protection
EU
Pb
Antifreeze protection
IU
Coil probe temperature (T3) greater than maxi-
Pd
EU
mum limit allowed in cool mode
Error due to difference in temperature between
Twout and Twin not in line with the operating
mode. The error appears in heat mode if Twout
PP
IU
is less than Twin for more than 15 minutes
UI: Indoor unit
UE: Outdoor unit
EN
126
Cause of fault and corrective action
1.The signal cables of the slave and master units are not correctly connected. After checking that all
the signal cables are securely connected and ensuring that there are no strong magnetic interfer-
ences, switch on again;
2. There are two or more hydronic boards connected to the user interface. Keep only one user inter-
face connected to the master unit and then, switch on again;
3. The start delay between the master and slave units is greater than 2 minutes. After ensuring that
the interval between the start-up of the master unit and slave unit is less than 2 minutes, switch on
again;
4. Conflict between the master and slave unit addresses:
When you press the SW2 button on the main slave unit board, the address code of the slave unit is
displayed (the code used normally goes from 1, 2, 3 ... to 15); check if a there is a duplicated address.
If there is a duplicated address, after switching off the system, set S4-1 to "ON" on the control unit
hydronic board and on the hydronic board which displays the "Hd" error. Switch on all the units again,
wait 5 minutes without the "Hd" error, switch off again and set S4-1 to "OFF". The system will be reset.
The RT/Ta board is correctly configured on the user interface, but the thermostat expansion board
is not connected or the communication between the board and the hydronic board is interrupted.
2. The EEprom is faulty; replace it with a new one.
3. The inverter module board is broken; replace it with a new one.
refer to H6
Refer to P0
-
-
-
-
-
-
-
-
1. The system has no refrigerant. Look for the leak, repair it and fill with the correct load.
2. The water flow is too low in cooling mode. Increase the water flow.
4. The electric expansion valve is blocked or the power supply has come loose. Try to release the
valve by gently tapping it. Connect/disconnect the connector multiple times to ensure that the valve
is working correctly.
-
-
-
1. Make sure that all the shut-off valves in the water circuit are completely open.
2. Check if the water filter need cleaning.
3. Make sure there is no air in the system (bleed the air).
4. Check the water pressure. The water pressure must be > 1 bar
5. Check that the pump speed setting is on the maximum speed.
6.Make sure that the expansion vessel is not broken.
7. Check that the resistance in the water circuit is not too high for the pump.
-
The unit will automatically return to normal operation.
-
1.Check the resistance of the 2 temperature probes.
2.Check the position of the 2 probes.
3.The probe connector is disconnected. Reconnect it.
4.One or both probes are faulty; replace them.
5.The four-way valve is blocked. Restart the unit to allow the valve to be released.
6.The four-way valve is broken; replace it.
Cod. 3541V941 - Rev. 05 - 06/2022
OMNIA S 3.2