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hybrid
21-11-2011, 08:39 AM
Hey guys, I have a problem with this York split ducted unit. First up I had what i thought was a faulty reversing valve. Having very high suction pressure to the point i could not hold my hand on the suction line at the compressor.

So i changed the REV valve, charged the system up and everything seemed to be running fine. Unit has run for at least a week and today i got a call back.

I checked the unit and the same thing is happening again. I can only put it down to the REV being faulty. I did not over heat the REV on install. Using wet rags to protect the valve.

This is very fustrating! Surely the REV is not gone again??? Cheers for any info!

I have tried energising the soloniod, no gas whooosh happens. The solenoid is trying to slide it though. I have take it on and off, gentle tap ect still nothing.

NoNickName
21-11-2011, 09:13 AM
It looks seized again. It may be the circuit is dirty or clogged by debris. An authopsy of the first 4-way rev valve may lighten up the issue.

cool_tech
21-11-2011, 10:18 AM
Hey mate
you can try and tap it or even put a stronger magnet or solonoid coil on the rev to try and free it up. I have a cps magnet which i have freed up a few rev valves with.

mikeref
21-11-2011, 10:49 AM
Hybrid, Firstly, welcome to R.E. Good to see another Aussie join in on this forum. As No Nickname says, the system you are working on seems contaminated. I don't think the valve is faulty. As there is no protection from compressor discharge to 4 way valve, i suspect debris in the system to be the fault. Maybe the compressor has already produced metal filings.. Mike.

cold.man
21-11-2011, 11:02 AM
when you say the system was running fine when you left are you positive about that.
could it not be possible the the comp is faulty with discharge pressure blowing into the suction.
i agree with the other repliies as of there is contamination in the system this is a possible.
what type of comp is on the system.
try pumping the system down.
did you pump down to replace the REV or did you reclaim the gas.
is the comp tripping on overload due to the high suction pressure?

hybrid
21-11-2011, 11:24 AM
Wow awesome fast replies guys, love it thanks heaps.

Cool tech - I might give this a go, see if i can get a stronger magnet from a supplier tomorrow.

Mike - Thanks for the welcoming :) Looking at the age of the unit, it does look like the comp has been changed out before. It is currently running a copeland scroll compressor. I had a look inside the old REV valve and there was evidence of tiny shavings, not alot but some.

Coldman- I am fairly positive that the system was running correctly after i finished charging the system.
Most of the time i take my time in commissioning units to make sure i dont get call backs so im sure that it was running fine.

I reclaimed the gas from the system, pulled a good vacuum and recharged the system with the same gas. As i stated to mike it has a copeland scroll on it. Is it possible to get discharge pressure out of the suction inlet on a scroll? There is no liquid line shut off to i can not pump down into condenser. The comp does have a internal overload but it was not tripped. Bit of a worry as the compressor was very hot and suction line un touchable.

I think if i can get the REV sliding again with a stronger magnet, i still would like to possibly do a clean up of the system as i do not know the history of it (burn out comp ect)

mikeref
21-11-2011, 11:53 AM
Hybrid. it won't take much to bugger up the workings of the reversing valve. I would be checking for metal or discolouration in the oil. No point sticking another valve on there if the same thing is going to happen. Remove the compressor and dump the oil. If the system is getting on in age, then it might be better to replace it..Mike ;).

exotiic
20-12-2011, 01:31 PM
Hybrid, did you find an answer to your issue? What was the result?

I am having a very similar issue at the moment, I have changed a reversing valve approximately 3 months ago which I believe now to have failed and had destroyed the Maneurop MT71 compressor. I reclaimed the refrigerant, changed the compressor, installed the filter drier, triple vacced the system and replaced with new refrigerant.

I started to commission on cooling cycle adding just under factory charge of 4.5kg and letting it run. Suction and discharge from compressor maintained low readings of 220kPa and 1200kPa. Tried the system on heating and the pressures were much improved at 400kPa and 2000kPa. Upon changing to cooling again to try the system the reversing valve energised and I could hear the refrigerant change direction but the suction inlet into the compressor was reaching 60 degrees C. Removing the coil allowing heating to change to heating mode and playing with it trying to see if the refrigerant pressures would stabilise gave no result, upon heating the system was performing very well yet on cooling the system would maintain the hot suction directly into the compressor after the reversing valve.

Would this be a leaking reversing valve?

jason09
24-01-2012, 03:36 PM
wot kind of metering devices (check valve could be leaking at indoor unit)