[stock2mal]

We had a new system installed just under 2 years ago. New gas furnace and AC unit. Everything seemed to work fine up until a few months ago, when the AC stopped cooling below roughly 80 degrees. We checked the difference in the temperature at the return and the vent, and called in the guy who installed it to check it out since there was only a 7 degree difference.

He checked everything out and finally said that it had a minor leak in it somewhere, but he couldn't locate it. He said it wasn't in the joints anywhere so it had to be in the main line. He tried to track it down, but could not. He gave us a few options, one of which included a thorough leak test that was relatively expensive, and we went with using a stop leak and refilling the coolant (based on his suggestion). The other solution was replacing the main line from the outside unit to the inside unit.

Well, it's about a month and a half later and the system doesn't appear to be cooling as well as it did. The AC unit outside has been making a horrible noise as well. I will try to get a temperature reading between the vent and return today.

Any ideas as to what could be causing this noise in the AC unit?

Link to video: http://www.youtube.com/watch?v=gzMQ18rxxaE

 

[fabrk8r]

I'd be interested in the temperature difference readings you get. That should help in diagnosing the problem.

It's too bad he recommended using the "stop leak". There really shouldn't be anything in a system except refrigerant.

The noise sounds like the compressor is failing. hard to say what caused it, but the first thing that needs to be done is get that condenser coil cleaned! I hope the evaporator (indoor) coil is cleaner than the outdoor coil. It should be if you've been changing the filter regularly.

 

[stock2mal]

I'd be interested in the temperature difference readings you get. That should help in diagnosing the problem.

It's too bad he recommended using the "stop leak". There really shouldn't be anything in a system except refrigerant.

The noise sounds like the compressor is failing. hard to say what caused it, but the first thing that needs to be done is get that condenser coil cleaned! I hope the evaporator (indoor) coil is cleaner than the outdoor coil. It should be if you've been changing the filter regularly.

The filter inside is changed regularly, and has never really been dirty when we have changed it. I knew I was going to get *****ed at for the cleanliness of the AC unit, I will clean it this weekend

He assured us that the stop leak would not be an issue, could this lead to potential problems?

 

[JJboy]

You need to clean the condenser coil to drop the head pressure. Also you need to fix the leak. Running an AC with low refrigerant could damage the compressor.

 

[Doc Holliday]

Pump it down and fill the lineset with nitrogen to 250-300 psia and he'll find the leak.

 

[beenthere]

Probably still leaking. Stop leak is not a fix, and I don't believe any manufacturer supports using it. And some void the warranty if they find it in the unit.

 

[loneframer]

I had a similar experience with my unit. Had the entire heating and air system replaced. It did great that Summer, but didn't cool well the next season.

Had the installer back, who put the gauges on it and added some refrigerant.

It did well all Summer, but the following season, no go.:furious:

Invited a new tech out to troubleshoot. It turns out, the A-coil had a very small factory leak at one of the elbows. Replaced the coil and it's been good for the last 2 seasons.:thumbup: