Hi everyone, hope you can help with my problem below.My outdoor condenser compressor keep stopping after about half an hour with the condenser fan still running. I have to stop the condenser for about 30-45 minutes before getting it to run again. Then the whole cycle repeats itself.Some remedies I did. I had a chemical wash on the coil of both outdoor condenser and indoor air-con unit. The air-con worked well for a month. Subsequently the problem resurfaces. This time I changed out the compressor and fan motor capacitors and I tried to wash the coil again, however the problem persist.Any idea what could be wrong ? I am having sleepless night battling the air-con. Toggling on and off. ~_~".Anyway the model is : Mitsubishi Electric MUX-24RV. It is an old unit for 16 years, still working strong until recently. Link to the manual : http://www.mitsubiech.co.uk/Data/M-Series/MSC(H)/2003/MSC(H)-RV/MSC-RV/MSC-RV_SM.PDF

WHen was the unit last serviced by an HVAC tech?

Sounds to me like you WILL be needing to call one now. Some of the possible issues require the right tools and the knowledge of how to use them.

Thank you for your response Sir.

Yes, I engaged air-con technicians to carry out the chemical wash and check on condenser as mentioned in my post.They reverted that the coil is dirty and probably the problem is due to capacitor. But they could not ascertain the actual problem. Also said could be due to the age of the condenser. But i do believe things can be fix and not because it is old.

Thus I did my own cleaning of the coil and change out the capacitor. The air-con is indeed colder, but the main issue is that it cuts off after 30-45mins.

Probably like you said, I need to engage a qualified HVAC tech to look into my condenser.

Hope others can share their opinion on this.

Thank you once again.

I need to engage a qualified HVAC tech to look into my condenser.

No, you need a qualified HVAC tech to look through your whole system starting with the THERMOSTAT. Just changing parts at the 'suggestion" of a "tech" guy is no way to trouble shoot, identify, or resolve performance issues.

Unless YOUR process started at the thermostat and ran through the indoor unit, you have skipped the most important part of the troubleshooting process, and if tech guy (Or YOU) didn't have a volt meter, you are just guessing, and that's expensive.

Your link didn't work so try mine.

MITSUBISHI ELECTRIC MUX-19TV - E1 SERVICE MANUAL Pdf Download. (http://www.manualslib.com/manual/784599/Mitsubishi-Electric-Mux-19tv-E1.html#manual)

Your problem does not sound like a dirty anything.. it sounds like a system that's undercharged (over charged can do that but it would have to have been done during a recent service likely during very cold weather), or is worn out and overheating.

What I meant by my question, is did they come out, try to diagnose the problem... or just come out to clean the system and replace the caps specifically at your direction?

I have to ask because some people will call them out with a very narrow scope to keep charges low, sometimes it is a false savings. Yes my HVAC friends say certain clients do that all the time...then try to get them to do extra that they weren't paying for.

Its not my field of work, ( but it is a fallback career path if I have to ) but I am licensed for automotive systems (principles are the same) and I have batted .900 on calling out the correct problems on a number of industrial 10 ton, 50 ton and 100 ton air handlers at my place of business to the contractors for the last 15 years.

And not all HVAC guys are equal... the HVAC Guys I worked with for years have told me my diagnosis is better than a lot of the guys they work with, and the only one of their clients. It was always a game, I'd tell them what I thought the problem might be, they would do their testing, let me know what it turned out being... and I was almost always right, not always, but usually.

Service centers aren't any better, Dealer or otherwise...took a company truck in to fix an intermittant A/C system which didn't work more often than it did, knew exactly what the problem was, but it had a service contract for maintenance, Dealer couldn't find it in the two weeks it was there, took it back, took it to a second service center, who wanted to basically replace everything....again, stupid because it needed one part that could be replaced in under 30 minutes and cost retail less than $200 at the dealer. Company finally decided to reimburse me if I fixed it myself. Ended up costing $50 (ebay part) and 30 minutes of time in my driveway...worked perfect for the next year when it was turned in.

Two subsequent cleanings was unnecessary, one would have been sufficient. That's one of the reasons I asked.. it looked based on your post like you were only looking at two possibilities ( cleaning and capacitors) and never looked at anything else.

Some guys will only do what you ask them to do... and nothing more, particularly if it involves extra work that would carry an extra charge that wasn't pre-autherized.