View Full Version : R125fj7w1

07-06-2017, 03:08 PM
Hello fellow engineers!

I am working on a split AC from Daikin model R125FJ7W1 right now. It is about twenty years old.

This year, after a little service, it was running only for 5 minutes every 5 minutes, so I started to look into the matter.
Recently, when turning the electricity on, it didn't start normally but the display showed "88". (The fans won't activate ever since that error.) From what I know that is not a normal start. The indoor units started as normal, though. Now when I changed a special switch in the connected indoor unit and changed it back after a minute (see pictures), the display would normalize and show an E0 error right after that, which would lead to the safety devices. I would like to know from you how I might be able to specify the error. Shortly pressing the pump down-button (yes I know, sorry, shouldn't have done that) activated the compressor. Can i exclude it from my search?


Thank you a lot for your time!

07-06-2017, 04:25 PM
Check the pressure switches and fan safeties, check that all plugs are correctly fitted.

07-06-2017, 08:44 PM
from what I see, you have a 7kW indoor unit connected to a 12.5kW outdoor unit....mismatch and will not work.

install monkey
07-06-2017, 08:47 PM
88 is initialisation - always shows when powering up indoor unit
e0 is outdoor safety device - not lp switch - or hp switch- theyre e3 e4
it will be condenser fan- that has a thermistor in listed as q1l q2l easy way to prove this is when it fails check you have volatge on each side of the pins - as its normally closed circuit - opens if overheat- easy way to test is stick a bit of wire accross the 2 wires of the plug- see if it runs longer- also compressor over current on the overload can cause this- 99% of the time its cond fan motor- youll see theyre controlled off relays ry1 etc theyre 2 speed- soetimes the relays fail- dont bother trying to resolder a relay - ive tried- sometimes its easier to hard wire the fan direct off the cont via an inline fuse

install monkey
07-06-2017, 08:50 PM
not a twinsplit is it?

from what I see, you have a 7kW indoor unit connected to a 12.5kW outdoor unit....mismatch and will not work.

08-06-2017, 10:18 AM
Thank you for clearing things up!
I made resistance measurements and everything was OK except for 1 fan: The resistance of the motor is "unmeasurable", the multimeter kept giving out different values between 100 Ohm and 5 MOhm. I'm not sure about the thermistors either: the resistances were 30/40 Ohm. We have a second AC in the storage which is the same model, in which the thermistors only had 6 Ohm. I don't think the temperature difference of 5-10 C did that - I think I'm overseeing something here.

EDIT: I want to add that pressing the pump down button, although specified in the instructions, wouldn't start either of the outdoor fans.

Yes it is a twinsplit. One of the indoor units has a twisted pipe though and I fear there's a big resistance for the cooling medium to pass. I thought it was smart enough to self-regulate its output in that case.

EDIT: 88 is what it shows at startup, but even letting it go over night wont make the controls get to normal display. (Neither does pushing any buttons.) Flipping the red marked switch, leaving it for one minute and changing it back though does the trick.

Updated link to the album... https://imageshack.com/a/wXwl/1

-Is one fan broken but both thermistors?
-Might the failure of the outdoor unit have resulted from having too little load?
-We have a circuit breaker for the AC and I just read about the crankcase heater - how much should I let it preheat before starting operation?
-Will I need to replace the pipe?

13-06-2017, 03:09 PM
Hey folks, I got good news.
The E0 came from a burnt fan, like in that other thread on this forum. The burnt fan probably came from the twisted pipe, which I could luckily twist back without any leaks.
So then I got an E9. Replaced the step motor of the EEV, didn't help. Replacing the PCB did the trick then.
Now this antique finally works!!

PS: I asked earlier why the 88 wouldn't go away. Turns out, the connected unit was set to emergency mode, not normal mode.

13-06-2017, 08:44 PM
Thanks for the update.