Mitsubishi Inverter 12k shuts down after a few minutes in heating mode

[LChaminés]

Hi again,
So I have a case of a mitsubishi inverter mini-split that stops working after a whyle (not even the fans rotate, although it stays ON) in heating mode (in automatic it doesn't heat at all), in heat mode it works fine for a few minutes than it stops and never restarts, unless you turn it off and on again (and it works for some more minutes and stops).

I suspect a thermostat problem but since it does cool normally (althought the client said that he feels that it's not as cool as it was before) I don't know.

This unit had a gass leak some time ago that was corrected and we applied a new full charge to it, i don't think it's related but then again, I don't know.

Any help is appreciated, thanks in advance.

[install monkey]

doyou have model number??

[install monkey]

in heating mode the fan runs in low low speed until the indoor coil sensor reaches 33 deg then it speeds up, cooling mode the fan runs in hi or low

[LChaminés]

Thanks for the replys, sorry i don't know the reference, i think it's n MXZ but I could be wrong, about the slow rotation of the fans, they stop afeter a whyle, stop as in full stop, and you can't sense anymore the warm air, it just stops functioning.

[install monkey]

http://www.mediafire.com/download/cpf21f0a2q3b2x5/MXZ-8A140VA_~_PAC-AK31~51BC_Technical_%26amp%3B_Service_Manual_(OC316revE).pdf
click on the link above for mxz service manual

[LChaminés]

http://www.mediafire.com/download/cpf21f0a2q3b2x5/MXZ-8A140VA_~_PAC-AK31~51BC_Technical_%26amp%3B_Service_Manual_(OC316revE).pdf
click on the link above for mxz service manual

Thanks for the link but i got the reference mixed, it's nopt a multi-spli just a normal mini-spli I think it's the MSZ-HJ35VA but i could be wrong but this time i think i got it right, sorry for the mess up..

[install monkey]

http://www.mediafire.com/download/td3enrrd2i5f16i/OBH647.pdf
indoor unit- theres a last alarm recall in here
http://www.mediafire.com/download/m5cpi133rdohi30/MUZ-HJ25%2C_35VA_Service_Manual.pdf
outdoor manual

[LChaminés]

Thanks, going to read a bit..

[LChaminés]

Hi again, and thanks for the replies, so I went to see the mini-split yesterday (it actually was a Mitsubishi Heavy Industries DXK12Z3-S, my bad).

Many strange things, first there appeared to be no r410a leaks, but the pressure OFF/Cooling/heating was always the same (around 14.5 Bar),compressor not pumping? clogged? thermostate not giving the right order?
Also, it didn't cool anymore , wich was hard to see since it was a cold day anyways but I didn't feel any "cold" air being blown out (forgot the thermometer, sad, so sad..).
In heating mode it did heat but aftera whyle (let's say 8 minutes) it slowly stopped the fans and started blowing almost "cold" air, not warm at all and the room was far from being warm (I set the temp to 30ºC and there was not even 20ºC in the room).
Since it did work well before, I assumed all connections were OK, I did check them there seems to be no problem with that.
So we called the Mitsubishi assistance and are waiting to see, I'll comment when I know but my money is either on a broken compressor or a clogged one (since it was a pre-instalation there might have been dust in the cooper pipes, we did blow it with N but that might not have "cleaned" them interely.

[ozairman]

Hi again, and thanks for the replies, so I went to see the mini-split yesterday (it actually was a Mitsubishi Heavy Industries DXK12Z3-S, my bad).

So we called the Mitsubishi assistance and are waiting to see, I'll comment when I know but my money is either on a broken compressor or a clogged one (since it was a pre-instalation there might have been dust in the cooper pipes, we did blow it with N but that might not have "cleaned" them interely.
If it's a MHI unit put it into Service mode and check the stop code history, that will give you a better idea of what has been happening.
To access service mode turn off the AC power to the unit and wait 2-3 minutes. Then press and hold in the on/off button on the Indoor unit and at the same time get someone to turn the power back on to the indoor unit. It helps if you have 2 people to do this, otherwise find a way to jam the button in whilst you go and turn the power back on (The On/Off button is part of remote control receiver window). If you have done this correctly the Indoor unit should beep and the Run & Timer light will flash together for 1.5 seconds. Then set the remote control to Cooling mode, Lo fan setting and 21°C setpoint. Count how many times the Run light flashes after the long flash and how many times the Timer light flashes, this gives you a 2 digit code to look up later. You can keep changing the remote setting from Cooling Lo fan 21 all the way up to 30° settings for the last 10 protective stop codes. Let us know what they are and we can help you.
Note Do not count the long flash, this is just the indicator that it is in service mode and that it is the start of the sequence.

[LChaminés]

If it's a MHI unit put it into Service mode and check the stop code history, that will give you a better idea of what has been happening.
To access service mode turn off the AC power to the unit and wait 2-3 minutes. Then press and hold in the on/off button on the Indoor unit and at the same time get someone to turn the power back on to the indoor unit. It helps if you have 2 people to do this, otherwise find a way to jam the button in whilst you go and turn the power back on (The On/Off button is part of remote control receiver window). If you have done this correctly the Indoor unit should beep and the Run & Timer light will flash together for 1.5 seconds. Then set the remote control to Cooling mode, Lo fan setting and 21°C setpoint. Count how many times the Run light flashes after the long flash and how many times the Timer light flashes, this gives you a 2 digit code to look up later. You can keep changing the remote setting from Cooling Lo fan 21 all the way up to 30° settings for the last 10 protective stop codes. Let us know what they are and we can help you.
Note Do not count the long flash, this is just the indicator that it is in service mode and that it is the start of the sequence.

Oh, too bad I didn't knew that 2 days ago but thanks, I'll keep that in mind, I'm probably
returning there in a week or two and I'll do that so I can post here, once again thanks for all the replies, I'll report in a week or so.

[LChaminés]

Just an update on this, the mitsubishi technician went to check the machine and said it was either dust or water/humidity, so we did a 24 hour vacuum and fresh charge, and it's been working well, althought we still have to wait to see if there's no permanant damage to the AC

[Greek_engineer]

24 hour vacoum?

[LChaminés]

24 hour vacoum?

Recomended by mitsubishi technician, although if there's "garbage" in a capilar (maybe this is not the right word) the all machine may not work