daikin L0 inverter problem

Hi all i have just taken over a ongoing problem site. It has 10 RSXY10GYAL r22 vrv twin compressor units. A few of the systems have L0 fault codes.

One of the systems has had a new inverter board set up. And still did not work after someone fitted previous.

I checked the wiring and all seems good.

I switched to emergency and unit runs perfect (as it bypasses inverter board and compressor).

I wired a 3 phase supply to the inverter compressor to check if it was seized.(all ran ok).

Daikin tech were no help as they said it is now a old unit.

I think the fault is the main pcb as the contactors for the inverter are not pulling in and none of the yellow lights light up. but the red light is off and the 2 green lights are flashing.

Any info on L0 fault code will be a big help . 3 systems have L0 faults so will need as much info as possible thanks robin.

see attached.

Sorry too big to attach, send me a PM with your email and I will send you the relevant trouble shooting page

pm sent thanks

Check all power connections are all tight and sound.
Loose connections will cause these faults as the inverter boards will not be charging up properly.

Regards
Jase

Hello Robin r33

If the compressor is OK and you replaced the inverter PCB then more then likely it is the R1,R2 or R3 resistors. You will find these in the inverter switch box. They are white rectangular things with a cable connection at each end. Power off, disconnect one of the cables on the resistors and measure the resistance. The resistance is about 33Ω I think. Its printed on the side of the resistor. If its open circuit then its blown and needs replacing. With out these resistors the system will trip on LO every time.

Let us know what you find.

Obi Wan

LO fault-Located in the inverter system.

Most likely to be in the inverter PCB. However daikin will recommend that all outdoor PCB's are changed as the fault in one board can damage another an so on in a chain reaction and if only one PCB is replaced then you will have a 95% chance of another service call for a similar problem.

Daikin also sell an INVERTER checker, this plugs in place of the compressor and if all six lights flash the PCB's are healthy. they are approx $70AU and save loads of time & $$$. Did you change just one PCB???

Hi everyone
Robin, as Obi Wan told you check the resistors on the left side of the power box.
Also check the contactor that lead 2 phases and the capacitors hidden in the metal box below.
Check the running current it must stay below 15 amps per phase.
On the unit equiped with new inverter pcb kit check the connections.
I will also try the new pcb box on another unit...
You may also have a problem with the oil return from the oil separator, check the temperature from the bottom of each (1/4 pipe) filter and capilary tubes just before the low pressure pipe ( 3/4 ). The temperature must be near the discharge pipe temp except near the gaz side.
Check the temperature difference of the accumulator maybe there's too much oil inside if the difference is high. This will create liquid back and L0 or E0 fault.
Hope this helps
rgds
cool#9

Thanks for all the replys.


The history is the unit had a L0 fault code so another company changed the inverter board and the problem was still there. After a lot of money the customer called us in to investigate.

The main pcb was not changed as you can see it is old and faded.

The unit works perfect on emergency.

Does anyone know when the orange indication lights light up as none of them are lit ?

neither contactor is pulling in.

The customer phoned me today to say the original engineer was bringing someone from daikin (scotland) to london to check over the system. The customer said she will phone me monday to let me know what the proplem was. I do not believe someone is coming from scotland. Ill let you all know on monday

thanks for all the help

I hope you got the PDF in the end....

Daikin has several good engineers around London, can't see why they would send one down from Scotland??

Where about in London is it and will you be back on site this week at any point? (I do like these old G series and I will be up in town with the Laptop)

In Scotland you only find the best!!:D

Quote:

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Originally Posted by Jase

In Scotland you only find the best!!:D

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Strange.....

I'm sure the saying was "Scotland is the only place you find the women in trousers and the men wearing the skirts"
:D:D

Quote:

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Originally Posted by The Viking

Strange.....

I'm sure the saying was "Scotland is the only place you find the women in trousers and the men wearing the skirts"
:D:D

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Hee! Hee! I'll give you that 1:D but surely, I thought vikings wear skirts too:p

I phoned the customer today and was told daikin had found a open circuit on resistor R1. Thanks to the people that helped.

Quote:

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Originally Posted by Obi Wan

Hello Robin r33

If the compressor is OK and you replaced the inverter PCB then more then likely it is the R1,R2 or R3 resistors. You will find these in the inverter switch box. They are white rectangular things with a cable connection at each end. Power off, disconnect one of the cables on the resistors and measure the resistance. The resistance is about 33Ω I think. Its printed on the side of the resistor. If its open circuit then its blown and needs replacing. With out these resistors the system will trip on LO every time.

Let us know what you find.

Obi Wan

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A round of applause for Obi then!

Thank you, thank you, thank you……. But really it’s an old Jedi mind trick!!!:rolleyes:

Just for info, The R1 resistor blows if only one phase is lost while the inverter compressor was operating.

Obi Wan

Quote:

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Originally Posted by Obi Wan

Just for info, The R1 resistor blows if only one phase is lost while the inverter compressor was operating.

Obi Wan

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Yes of course....instantaneous power failure; loose wiring or other power supply problems will cause L0 fault;)

Jase

Think I read somewhere that condensor fan thermal overload can also cause an LO fault