daikin ducted just turns it's fans off

[paul_h]

Got a ry125luy1 here, runs for a few minutes in cooling mode fine, then just shuts the outdoor fans off and cuts out on E3 hp error.
Anyone know why it's shutting the fans off? I checked thermistors, seem OK (12k for all but 77k for discharge.
Fans start up and run fine after resetting the power

[Temprite]

Hi Paul.

I think that model has a HP switch. What is discharge pressure when it runs?

Cheers.

[paul_h]

yes, it has a HP switch. It trips HP because it turns it's condenser fans off after running for a few minutes.
So the compressor is running without fans and trips the HP.

[frank]

I've had this before Paul, and Brian UK posted the same question just recently on a RY71.

The ambient sensor (back of coil) can be out of calibration, giving false signals to the PCB, making it think that the ambient is very low, therefore there is no need for the fan to run.

Put the ambient sensor into the coil between the fins and see if that forces the fan to keep running.

[paul_h]

I read that thread frank, thanks for your input BTW.
While on site I got my laptop out and USB modem and dialed into the this forum and read that :D That's the main reason why I took thermistor resistances before creating this thread right there.

Guess I need to know what operating proceedures daikin use, ie in what circumstances would it want the outdoor fan completely off rather than just low speed. Only when I know that can I begin to trace back to a fault somewhere to find why it's shutting the fans down. If no such program exists then it can't be sensor fault causing it. I've been reading daikin manuals this afternoon, and never found an instance where they would want the outdoor fan completely off in cooling mode. (edit: not that it doesn't exist, maybe it does, just I don't know it so don't know where to start fault finding)

But why not just low speed in low ambients? why not just one fan? etc etc etc - I've no idea when it comes to daikin, and doesn't make sense to ever shut both fans off (from high speed) in cooling mode; and 12k resistance on the thermistor for outdoor air seems right to me anyway :confused:
edit: why not shut down on sensor fault instead of keep going until trip HP? Why not take note of the liquid line thermistor reading and not do something so daft as turn the fans of completely?
edit:so many questions ;)

[Obi Wan]

Hi Paul,

Can you confirm the model number please. Is it an R22 or R407C system?

Do both fan motors stop? Check the relay on the PCB for high speed, may be faulty. (The unit thinks its switching to High speed but the relay is not switching).

If you have another like for like unit, swap the PCB and see if the fault travels.

Regards

Obi Wan.

[paul_h]

Hi Paul,

Can you confirm the model number please. Is it an R22 or R407C system?
R22

Do both fan motors stop? Check the relay on the PCB for high speed, may be faulty. (The unit thinks its switching to High speed but the relay is not switching).both stop from what seems to be already high speed, another reason why I think the ambient thermistor is reading the 33C ambient fine on start up


If you have another like for like unit, swap the PCB and see if the fault travels.

No other like unit.

[exotiic]

I had a similar situation with a single fan system dying after several minutes due to bearing failure and thus overheating but obviously it seems very doubtful that both fans would be at the same time.

[paul_h]

Yeah, somewhat common for single fans daikins to have problems, mainly inverter systems, not the a/c fans on 3phase ducted daikins.
I've seen a few faulty motors (replaced 3 last week on a bunch of 10 y/o dual fan ducted panasonics), and some old ducted mitsubishis, but that hardly happens on hardly used residential a/cs only 6-7 y/o, mainly older and commercial installs when talking about 240v ac fans.


edit for daikin guys:
The motors, capacitors, bearings are good.
Outdoor air thermistor soon after shutdown was 12K, which is 36*C. By the time I tested the discharge thermistor it was 77K, ie 56*C, and the condenser thermistor was also 12K or 36*C.
Both the condenser and outdoor air were the same values, so I checked voltage across, both 1.23V DC so if one was assumed good, both tested exactly the same in volts, meaning both must be good.

Can the indoor in an 'iced up' condition stop the outdoor fans?
It wouldn't make sense, should just turn the compressor off, but daikin is the devil to me.
At the point where I should maybe say "it's an old R22 system and it should be replaced", like you guys do in the UK these days ;)
Just joking, but anyone out there that knows why?

[a/c.king]

dear paul-h
you have problem with daikin ducted unit that its shuting its fans sadnly and gos into HP trip by er code?

selution
you back to the unit started if the fans run warm up imbent sensor located at back of the unit and it the fans stoped working after 5 mint from worming imbent sensor that means the fans speed caycle relays located on the outdoor PCB are not closing the cercuit. faulty OUTDOOR PCB. outdoor PCB cost $280 AUSTRALIAN DOLER.if u live in aus i can borw u new outdoor PCB to try it if your problem solved you pay me...................


sam
a/c king

[Paul84]

I work on Daikins quite a bit. I briefly read over this long read and I agree with 'AC KING'.

The fan relays on the board cycle LOW, HIGH, HIGH-HIGH. These onboard relays jam and drop power to the motor.

This might sound bad but if you hit this relays with a screw driver handle the second the fan stops it may free the relay and start on the selected speed (obviously this is only for diagnosing and confirming this is the problem is with the PCB).

Hope this helps =)

[paul_h]

Thanks.
I was 90% sure it was the PCB myself, as I couldn't find any mode of operation that would cause the fans to stop due to a bad thermistor reading in cooling mode, and they (thermistors, fans etc) seemed OK anyway.

Just had a small reservation as I have had fan problems on a ry250luy1 before, and changing the PCB didn't help, but that was a heat mode fault which of course uses the indoor thermistors etc to cycle the fans.

[Paul84]

Wait...Sorry to give a bum steer. Im thinking of RY100KUY1 (single fan). This wouldn't affect both fans simultaneously. Maybe triple check your sensors =S.

Maybe good idea to check thermistors with different temps - not just ambient. In heating I had a liquid thermistor on the outdoor coil accurate down to 10degc and only found the sensor faulty using COLD water. This didn't directly affect the fans but the defrost, but all the same.

[paul_h]

Do daikin have 2 separate fan relays though? Like do they ever run just one fan solo?
I know all about sensors reading fine in resistance at a certain temp, but still be faulty, very common with domestic refrigerators.
That's why I referenced the 12K ambient sensor with the 12K condenser/liquid sensor and made sure that the voltage across is the same, normally with voltage, good is good no matter what temp as you don't get the 'surprises' you get if only relying on resistance at a certain temp..

[Paul84]

Both Fan motors have separate plugs. Next to the plug pins (C,L,H,HH) you can see the relays. I'm not 100% sure about fan cycling. Heating and Cooling will be different. FYI running the unit in FORCED cooling by OD dip switches forces fans in HIGH only.

I've never had indoor coil temps effect outdoor operation. Thats all overcome by the EXV and fan control. Based on your thermistor checks, you'd have to assume the pcb is corrupt =S.

[paul_h]

Also, I've got a ry100/125kuy1 PCB here, and you can see the 6 relays, 3 for each fan for low, high, HH as you say.
But the PCB for the ry125luy1 looks completely different. (I don;t even remember seeing relays next to the fan plugs, but maybe I remember wrong)

[Paul84]

The K and L will be similar in operation. I 'think' the fans have individual operation (could be for heating only) as looking at the wiring diagram for both the K and L series the relay contacts are labelled differently. example Fan Motor 1 L,H,HH - K8R, K9R, K10R. Fan Motor 2 L,H,HH - K5R,K6R,K7R.6387

[Below 0]

I have just replaced a board on a ry125 which wouldnt switch lower condenser fan on and due to the ambient the upper condenser fan would cycle but was not enough to prevent an hp trip. The quick fix was to splice both fans onto one of the white plugs to keep customer happy while replacement board was ordered. The problem was a burnt joint on the back of the board which I have soldered so I now have a spare for emergencies. I see you say both fans are not running so wonder wether the x2 or x1 terminal has a bad joint and cuts both out under load. I have replaced 3 or 4 of these boards in the last 6 months and reckon you just have a case where both have failed at once. Un clip the board and turn it over bet ya there is a bad joint.

hope this helps.

[Temprite]

The K and L will be similar in operation. I 'think' the fans have individual operation (could be for heating only) as looking at the wiring diagram for both the K and L series the relay contacts are labelled differently. example Fan Motor 1 L,H,HH - K8R, K9R, K10R. Fan Motor 2 L,H,HH - K5R,K6R,K7R.6387

Correct me if I'm wrong but if you check the wiring diagram out the main active that supplys the fan motors looks like it goes in series through two "thermo switches" which I am guessing are overheat protection for the fan motors. If either open circuits then you will lose the main active that supplys both fans. You could bridge these out and run the unit and check for continuity on these switches after a couple of minutes and identify the faulty fan.

My bet is one faulty fan motor.

[frank]

Correct me if I'm wrong but if you check the wiring diagram out the main active that supplys the fan motors looks like it goes in series through two "thermo switches" which I am guessing are overheat protection for the fan motors. If either open circuits then you will lose the main active that supplys both fans. You could bridge these out and run the unit and check for continuity on these switches after a couple of minutes and identify the faulty fan.

My bet is one faulty fan motor.
That common feed through the motor O/L's also provides the supply to the HP switch and then the compressor contactor. Paul states that the fans stop after a couple of minutes and then the compressor continues to run until the HP pops. I would guess that if the feed is interupted by the fan O/L then the main contactor would drop at that point?

[paul_h]

Makes sence Frank, that would result in the old "outdoor protection" error "E0" if I remember right...

[Temprite]

That common feed through the motor O/L's also provides the supply to the HP switch and then the compressor contactor. Paul states that the fans stop after a couple of minutes and then the compressor continues to run until the HP pops. I would guess that if the feed is interupted by the fan O/L then the main contactor would drop at that point?

Dead right discount that then...
probably should have looked further down before posting:o

[frank]

We can discount a solder break in the main common feed to the relays, as both fans work then stop.

It's obviously the pcb dropping the on board relay's which power the fans. As both fans drop out together, the control logic would seem to be either getting the wrong input information or no input information at all.

If all of the sensors check out OK, I would go with a corrupt pcb.

[Paul84]

I agree with Frank. You may have to make an educated guess that the PCB is corrupt.