Mitsubishi PUMY P125Y error code 4250

[gjp]

Hello everyone

I have a mitsubishi pumy p125 y (3 phase) system that works without problems for about 4 years .Recently when the system runing i take the 4250 error code at the outdoor unit that appear 2 or 3 times in a period of week at a specific time ( between 07:30 and 8:00 am).
The only thing i observe is that the power electricity company increase the voltage from 380 V ac to 400Vac with unbalance between phases.
When i measure the R-S- T voltages i take 403-421-412 v.
I have two questions 1) my system have the problem or the electricity company is responsible for this
and 2) is there any problem for the system life (compressor ,electronics ,etc)when the system stops and the 4250 error code appears?

thanks for any answer

[superswill]

4250 =

city multi

Inverter IPM/bus over/under current detection, possible compressor fault, IPM damaged, disconnect compressor and measure inverter output all phase must be balanced

Mr Slim 4R410A

power module, check compressor connections, mains voltage, compressor, power circuit board failure

hope this helps

[Thermatech]

4250 is IPM problem like overcurrent or power supply problem.

In this case your power supply is very poor with imballance between phases.

But this could be what some call
' floating neutral '
This is caused by a poor connection of the neutral line at some place in the power supply circuit to the unit.

With the system at standby & compressor not running
1/ measure voltage between earth terminal & Neutral terminal at the outdoor unit.
This should be less than one volt.
any more & you could have a poor connected neutral.
2/ measure the voltage between earth & each phase & then Neutral to each phase. The readings should be the same within a few volts.

When you do all the above test measurments with the compressor running all the readings should be almost exactly the same
if the voltage drop at compressor run more than a few volts then you need to investigate the power supply further.

The problem could be a fault with the power supply to the building from the power supply company
or
it could be a problem with the power supply circuit in the building
or
at the outdoor unit 3ph isolator.
any place where the cable is connected at a terminal is suspect if there is any measured voltage between earth & Neutral.

Resolve this problem as soon as you can otherwise the inverter can be damaged.

[gjp]

thank you superswill and thermatech for your answers.

1)The voltage between earth and neutral terminal at the outdoor unit is 0 volt ( with the system at standby and compressor not running)

2)the voltage between earth and each phase and neutral to each phase are exactly the same regardless of compressor run or not.

The building and the wirings are new (4 years old) so i believe that i have poor power supply.
The voltage drops frequently in my area.

thanks again

[gjp]

finally i solve the problem with a 3 phase voltage stabilizer at 15 kva .The mitsubishi works fine

[peachy]

hi guys. all my indoor units just stopped producing cold air last night. the error came out the same as the original poster—4250. the service guys said they will replace the IPM board and I'm wondering if there are just being too hasty w/ replacing it. The outdoor unit is single-phase Mitsubishi PUMY-125VM. Can't these board be repaired? Doesn't anyone repair electronic parts anymore? Seems like it's always the board and it's never repaired but always replaced. Help? Comments? Suggestion?

[Thermatech]

If you can find a local electronics company who specialize in circuit board diagnostics & repairs then please go ahead & use them to test & repair the circuit board.
If you find that this is a cost effective option then please post the details here so that we can also use this option.
You will most often find that air conditioning engineeers are well ,,,, air conditioning engineers!
they are not qualified experianced electronics engineers.
So most often when there is a problem with a circuit board the cost effective solution is to install a new one.

[peachy]

thanks Thermatech. so I just received their quoted price of almost US$800 for the board plus 3 months to wait for it. :rolleyes: i nearly fell off my chair. is this really the going rate for this board? are there online places that I can purchase this board from? of i believe the unit runs on 220V

[peachy]

I just downloaded the service and technical manual for the unit and for the 4250 error code it list a whole page of things to test and possible cause although it does say it's the IPM. I'm just wondering why the technician just basically went to the unit opened it up and right away says it's a replacement of the IPM board. should some poking here and there w/ the voltmeter be done as well some other test.... he practically just asked me to turn on the indoor unit and says the compressor is not running, we'll need to replace the IPM.

[peachy]

I called their HK office also (via a friend) and they don't have the board in stock also... informing my friend instead that it's an old model. I wonder why they think new units are the ones that will have broken parts.

[peachy]

Was hoping someone could tell me if the part really isn't that pricey. Looks like they will just be replacing the IPM and some Amp board. Unbelievable how expensive this board is. Apparently a few in my bldg also had the same issue.

[peachy]

Mitsubishi guys said I can use this part number instead.... R61 A42 249 (IPM) and R01 37A 313 (GA board). can anyone say if this is indeed correct?

[stufus]

Yes both part numbers are suitable for your machine according to the tech site !
Cheers
Stu

[peachy]

stufus.... Thank you so very much. now at least i'm confident that the 2 parts are indeed interchangeable. Is the 700$ price reasonable in your opinion?

May I know where this tech site can be found?

[stufus]

700 dollars is about 510 Euros ,so for a non trade customer is not bad.The tech site is Mitsubishi's own technical site for affiliated account holders.I think non account holders can use it subject to their(Mitsubishi) approval.
Cheers
Stu

[peachy]

I guess i'll be going this route. hoping for the best. thanks to all.

[peachy]

So after several delays the technicians came by with the new IPM board and the other board that's mounted on top of it. After the install they powered the unit and it didn't start up. No lights. Nothing. So the guy checked and found a fuse that's burnt out. Replaced that and it still didn't go. Apparently there's a ground inside the compressor that supposedly caused by a broken relay that's inside the compressor. So now they are saying I should replace the compressor. By now I'm thinking WTF?!! Then he continued that the inverter board will need changing also bec the compressor shouldn't be changed without replacing the inverter board as one of them will just break the other. Oh the control was reporting 4220 this time. Why am I starting to think that they are just doing a trial and error method to fix the unit obviously at my expense. If I'm replacing AT&T that then I'm probably better off buying a new outdoor unit but my body is so against it. The unit looks good still and it's now going to the landfill? Is this the lifespan of AC? It's so wasteful financially and environmentally. You guys worked with these type of ACs. Is this normal? I have a feeling this is going to cost me around 4 grand.

Ok with that many parts

[peachy]

so needless to say i'm pissed that i'm being somewhat forced to buy a new outdoor unit with this situation. a 7yr old AC system and it's already ready for the landfill. for the 3 yrs i've owned this apartment i've barely used it.... perhaps 1yr MAX (spread over 3 yrs) i stayed in that unit. the rest it was vacant. the person i bought the unit from didn't stay there everyday also. he was a bachelor that lived in another city 5 hrs away. my guess is the techs just don't know how to really diagnose and fix the issue. it's a "let's try this one.... then this one.... ok this too".