[midas28]

Hi
Our Carrier HVAC unit's coil was leaking water over our basement floor. For about $700 we had it and the pan replaced. The tech charged it back up and it worked great for about 24 hours. Then it started to barely push air and that air was not cool I called the company. They came out and said the original tech didn't charge the unit enough (since it was an older unit it needed more than the industry standard)
He charged it and it worked great for about 48 hours. Now the same thing is happening. While water was leaking on our basement floor, it worked fine before the new coil. I have to call them back, but I wanted to be somewhat knowledgeable. It just seems a bit suspicious that now that we have a new coil it isn't working correctly. Is there any reason this would be happening---incorrect installation, incompatible parts, etc.

Any thoughts would be appreciated.

Thanks!

[hkstroud]

Did 2nd tech check the first techs soldering for for refrigerant leaks?

[midas28]

No he didn't. I don't understand the terminology but he said the first tech only filled the refrigerant up to "11" and because it was an older model it needed to be charged to "17". He thought that would do the trick, but it only seemed to do so temporarily.
Thanks

[ma0641]

Sounds like a coil leak to me. Unless you have a 5 ton+ unit with a very long lineset, 11-13 # is about average. 17 seems like a lot.

[hkstroud]

Our Carrier HVAC unit's coil was leaking water over our basement floor.

That probably occurred because the pan under evaporator coil rusted away.
When air is cooled the moisture in the air turns to water. The pan under the coil catches the water and lets it drain out a condensate pipe to an acceptable place.

When the part of the system outside compresses the freon gas it makes it release the heat. When the freon comes back inside and the pressure is released, it expands and absorbs heat. That is how the system works.

In order to replace the rusted out pan, the first tech replaced the part inside where the freon expands. To do that, he cut the tubing that takes the freon outside. He put in the new part, called an evaporator coil (with a new pan). To do that he soldered the tubing to the new coil.
He then put the freon back in the system. You have to put the correct amount of freon in the system. If you put too much the freon it can't expand and absorb the heat. If you put in little freon, it will expand too much. If it expands too much the moisture in the air will turn into ice, not water. This ice build up will block the air flow.

Properly charging a system is not easy. There is no certain amount of freon used, it all depends on how big the system is and how long and big the tubing between the inside and the outside is. Charging the system is done by measuring the pressure and the temperature.

When you solder pipe or tubing, you sometimes have a leak. If the first tech properly charged the system but had a leak, the system would run for a period of time. But as the freon leaked out, the system would have to little pressure and ice would form, blocking the air flow.

If the second tech just recharged the system and didn't check for leaks, he is not to bright. He put more freon in but it has leaked out just like before and the same thing has happened.

Call his boss.

[midas28]

Awesome. Thank you. They are coming out Friday morning. Now I can sound somewhat knowledgeable and insist they check for leaks.
While it is a rather large HVAC company that has been in business for a while, it was the Service Manager who came out Saturday morning and didn't check. Makes me not have a lot of confidence in them.

Thanks again to everyone!

[ma0641]

When they are charging, watch the gauges. Look up AC head pressure on Google and It will give you the ranges and ambient temps for 22 and 410A.