help with a fujitsu system please

[casino]

had a call out a few weeks ago a fujitsu system A0Y25RWDL, the system was not heating or cooling, connected the gauges and there was no suction or discharge difference when the compressor was running and the compressor was a little noisy as well so checked the compressor with me megger etc and volts and amps and all seemed fine nothing out of the ordinary so after a think I de-brazed the compressor and ran it on its own to see if there was suction or discharge from it as maybe there was a block in the system. The compressor was very very weak so we stuck a new one in. now whilst we were looking at this we noticed the system had been getting very hot as the black sound isolation they put around some of the pipes had melted.
we also noticed it had a new changeover valve at some point and looked like it had been getting very hot to so we put a new one of those in as a caution.
all went in and working ok BUT the condenser coils are getting very hot and the casing is getting hot to (44c) when in cooling, suction line reads -6.3c discharge 14.1c and the coils reading 43.5c apart from 1 coil that read 27.3 air off condenser is 57.4 and running at 62psi.
in heating suction line is reading 127c discharge 50c and I noticed a couple of coils were freezing the same ones that were reading lower temp in cooling running pressure on low side is 300psi in heating.
Standing pressure is 145psi and the correct amount of refrigerant has been added (2.070kg). Changeover valve is working ok also.
Replacing the compressor seems to have cured the symptom but not the cause so can anyone suggest anything for me to try when I go back on Monday.

Thanks for any help

chris

[taz24]

Replacing the compressor seems to have cured the symptom but not the cause so can anyone suggest anything for me to try when I go back on Monday.

Thanks for any help

chris

I don't know an imidiate solution to your problem but.

What is the history of the unit?
You found things like the four way valve to have been changed which would suggest that you have inhereted this unit from sombody else?

Is it possible that it's always been like this?
In my experience you only get out of the cond what you put in the evaps and comp.
If you are putting in more that you are getting rid of then it will have no option but to overheat.
Is the system one evap or more? are the evap/s matched correctly to the condensing unit?

Like I said no real answers just more questions but again in my experience you can't beat
giving it a good dose of looking at.
Just fit the gauges and with thermomitor in hand watch it run for a few hours through the cooling and heating cycle.

Good look
taz.

Ps for what its worth it sounds like you have done all that you can and you have done it well.
Cheers taz.

[casino]

Hi taz24,

we have a service contract with this customer which have 30 split systems and this is one of them, there are 7 identicle fujitsu systems sitting next to each other (same as the one i'm working on), other companies have been at these before yes.
it is a single cassette split and has been running ok for years however i cannot say how long this unit has been overheating to cause this problem but i don't want to let it go as i could if i wanted to and have the compressor fail again, seems the overheating or the cause of the overheating made the compressor loose its suction and disharge function.

the temp from the discharge pipe coming directly out from the compressor was getting very hot as well.
we ran ofn through the pipes whilst everything was off as well to see if there was a dead blockage but all seemed fine, dificault to tell completly with the capilary being so small.

can you explain your words
"If you are putting in more that you are getting rid of then it will have no option but to overheat."

the coils are clean in and out.

[taz24]

can you explain your words
"If you are putting in more that you are getting rid of then it will have no option but to overheat."

the coils are clean in and out.

What I meant was the cond should be big enough to cool the gas from the evap and the comp combined.
If it does not then that would be the problem.
If the system is the same as others around and has been there a few years then everything should be ok.
Check the amount of gas in it.
Could the system have a longer pipe run and therfor be undercharged?

taz.

[Andy AC]

Is it a R407C fujitsu?, if it is and the other ones on the site are, get used to changing compressors. The R407c ones seem very weak and prone to failure. We had two go down on the same site at exactly the same time, installed at the same time,side by side, never abused, just went like yours, no explanation at all.
We've never changed a fujitsu R22 or R410a compressor, but quite a few R407c ones.
As Taz said earlier it sounds like you have done all you can just keep an eye on it and keep your fingers crossed!

Andy

[casino]

Hi Andy AC,

its an R22 one and it is possible that this unit was always this hot I suppose but having a good service contract with this customer I didn't want to leave it this way as its not right, we'll only get called back if it goes again and will have to replace it under our warranty and if that would be the case it would be never ending.

Anyone recon a small blockage could cause this excessive heat at all even though I ran ofn through the system and it seemed ok.

[wineman]

there r plenty of people u can ask b4 u do anything at all seems ur guessing

[casino]

there r plenty of people u can ask b4 u do anything at all seems ur guessing

Hi wineman,


not to sure what you mean by that but i needed help on this which is why i posted on here (to aks people.)

and yes i'm guessing here as i'm not to sure what could be wrong with the unit which is why i'm asking people.

i'd be happy to listen if you have anything that could help me out.

cheers

chris

[nike123]

all went in and working ok BUT the condenser coils are getting very hot and the casing is getting hot to (44c) when in cooling, suction line reads -6.3c discharge 14.1c and the coils reading 43.5c apart from 1 coil that read 27.3 air off condenser is 57.4 and running at 62psi.
in heating suction line is reading 127c discharge 50c and I noticed a couple of coils were freezing the same ones that were reading lower temp in cooling running pressure on low side is 300psi in heating.I will concentrate at this (underlined text) point.
From refrigerant diagram for outdoor unit AOY25RNAL (indoor unit AUY25RLD-W) is visible that outdoor heat exchanger comprises from two parts , and every part has his own filter and capillary. It's necessary to check the fall off temperatures across filters and after the capillary. If, even a little bit, differentiates one branch from other I will change the whole capillary assembly (part 420) and both strainers (part 992).

P.S. Next time, please, correct model number!

[Danny11]

Hi pal

I know this might sound so simple but i had a same problem months ago so..... check that your controller dip switches are set right inside the controller.

This could be the problem even though the controller is ok and no faults are showing,it still might not be sending the right signal to the indoor.

Cheers
Danny (danny@airconsquad.co.uk)

[casino]

Hi nike123,

Ah I put a 0 instead of an O but apart from that the model number is as it said on the label on the condenser, strange you say that because I could not find anything relating to that model number and I checked the model number a few times as well. None of the suppliers questioned the model number when I priced and ordered the compressor. (£260 difference between suppliers by the way, huge difference)

You mention the diagram for this unit...do you have it handy so I can take a look please.

Thanks for your post

Chris

[casino]

just seen danny11's post which is again interesting because when we were testing this unit to make sure the compressor had failed the controller stopped working, display was still there but could not use the buttons so we checked one of the other same controllers for another unit and the dip switches were different so we changed the dip switches to the same as the other controller, I believe the difference was if the power failed on the unit it came on automatically where as we set to not to and it worked again.

[nike123]

I also could not find, on Fujitsu site, model no. that you said and nearest match is what I said in my post.
For that model, I could send you service manual if you PM your e-mail. ;)

[nike123]

This is diagram!

[casino]

Hi nike123,

i found the servce manual through google and it has your diagram on yes.

if you go to page 26 of the service manual that shows the exploded view but its not quite the same, the compressor is not the same as that and part 259 conects to the bottom back left of the compressor not the top and part 333 conects to the side top right hand side of the compressor, also has 4 fixing holes to secure the compressor some other bits look different to.

i didn't get a chance to go back today and it may be next week now so i'll do more temperature tests then like you have sugested and see.

thank you for all your help on this

chris

[paul_h]

Those temps are bad, where are you measuring them?
Have you done a comparison of the suction and discharge pipe temperatures:
i)at the compressor
ii) discharge in and out of reversing valve
iii)suction in and out of reversing valve
Suction before service valve, after service valve, and before and after accumulator.
-6.3 is far too cold for the suction pipe temp (unless you meant sst)
There's definatly a restriction for the discharge to be so hot and the unit charged with the right amount. If the suction pipe temp is so low that points to a rescrition on the suction line somewhere.
You'r going t have to trace the restriction by taking pipe temps everywhere I think.

[nike123]

It would be nice if you could provide us with feedback on this mater.:(

[Stevo1978]

This might sound a bit drastic but couldnt you change the whole condensing unit if there still available. Just explain to the customer that there is a blockage somewere in the system that you are unable to clear. Think this may save your company and the customer a lot of time and money in the long run.