Daikin E3 fault on ducted RY125LUY1

Hi everyone,
I'm hoping someone might be able to help me out with fault finding an E3 (HP switch) error on a Daikin unit thats 11 years old.

Being right on the new year I can't get anyone for about a week and this week in Brisbane Australian it's 36 degC so it's hurting with no cooling.

The unit runs and seems to start the compressor for say 20 seconds then cycles it off again. The fans don't run at all. The error code comes up after a few minutes. I'm not great at refrigeration, but have checked the following;
- The two PCB fuses are ok
- The HP switch has continuity
- The electromagnet switch for the main power was heavily scorthched (contractor pads) from many years of hard labour, so I cleaned the terminals (no luck fixing the error)
- The PCB green LED is blinking saying no board errors
Everything seems ok, nothing black on the board.

What do I check next?

Thanks for any help.

Cheers
Cameron

E3 is high pressure cut out.
It may be caused by your fans not running while the compressor is working.
Change the 2 fan plugs over on the pcb and see if the other fan runs.
Possible that you have a burnt out condenser fan motor after 11 years

Thanks Frank. It'll do some swapping. Both the fans don't trigger so I was assuming it was a common problem somewhere. When I found the crusty contacts in the electromagnet switch I though "bingo" but to such joy. I have a working RY160 but I'm hesitant on part swapping without a plan.

Thanks Cameron

Okay,
I've tried swapping the fan connections on the pcb. No luck unfortunately . I paid a bit more attention and it seems the compressor runs for 15-20 seconds then shuts off. It doesn't run long enough to build much heat so I think the fans aren't running as they don't need to. It almost seems like the gas doesn't have a full open path to flow to. The compressor shuts down for a minute or two after the short run. It then repeats the process. After a number of these cycles it stops on the E3 overpressure error.
Thanks for the help.

I think that the fans not running are causing the high pressure cut out, but without a service manifold fitted, it is hard to make a firm diagnosis.

Do you have the skills and kit to electrically test the fan motors and the output from the pcb?

Not familiar with the model but have you checked the pressure transducer? They have a VDC to the pressure table. I've had to replace two in 5 years. They will cause the same symptoms that you're describing. Cycling on the HP switch before locking out with no or little outdoor fans.

Hi mate,
Had the same scenario a month ago.
Most likely HP transducer.
It is in the circuit with the HP switch.
The HP transducer brings on the condenser fans by differential with pressure and DC volts.
Therefore if it's faulty it will not bring on the condenser fan/s and thus cut out on HP via the HP switch.
Unit doesn't have to run long to build up High pressure. Just think how fast that compressor is cycling.

It works on a scale from roughly .5vdc-5vdc.
Standing pressure measured at the hp transducer for R410a is about 1.2vdc.
But you have to check this running as well. As I have found they test ok at standing pressure but once running they fail.
Put guages on and monitor the pressure compared to vdc on the hp transducer (should be able to rest the multimeter leads in the back of the plug) the vdc should slowly raise with pressure according to the chart. See attatchedAttachment 14469

Not a 5 sec fix. Need to pump unit down and sweat out faulty transducer and Braze in new one.
Unless you have the quick connect Schrader type.

Good luck,
Keza

On the 'L' series, the hp switch is a 2 wire

Hi Guys,
As a wrap up, thanks for the advise. After spending way too long trying to work it out, I managed to get a professional out earlier than expected. It's the PCB that's dead. It looks fine, no heat marks but it's not starting the fans.
I'm now bracing myself for the quote!
Thanks again for all the quick replies.
Cameron

Thanks for updating us all Tupperware and welcome to the Forum!
So often New members ask their question and then disappear.

Grizzly

If that's the older type where fan speed is controlled by different windings then it seems to be common the relay had failed. Perhaps one conked out months back but had to wait for the other to also give up before it became obvious.
My guess is the contacts get burnt with repeated switching over the years.
If you fancy a play you can hunt down a relay and solder in, might work.

Cheers,
Andy.