outside unit works, fan works, but air is not cold

I have quite weird problem with my AC.

This is a central AC. 8 years old.

It can work fine few days but then air suddenly becomes not cold anymore.
Outside unit works, fan works, but airflow is not strong and air is not cold.

If I turn it off in the evening and turn it on next morning it will work fine.

The interesting thing is when air is not cold the fan works, but airflow is weak comparing with when AC works fine.

Also AC can work fine some hours or some days but then air becomes not cold anymore and the only way to make it working again is to turn it off for some hours (about 8 hours).

What it can be?

Thanks a lot!

 

It is probably freezing up, which accounts for the low volume of airflow. By letting it sit you are allowing it to thaw out and resume operating somewhat normally, but it is not.

If you have it running, and tomight find that it is not cooling and again has a reduced airflow, go out to the compressor unit outside and view the tubes that are between your house and the unit. Quite likely you will be able to verify that it is freezing up.

 

I agree with Mdtaylor. How does your air filter look ? A dirty filter is a very common cause of freeze ups.

 

Thanks a lot for your answers!

I've checked outside unit right now once it stopped working. Inside everything is in ice. So you are right.

I'm going to buy and install new filter tomorrow.

But what to do with this freezing? Why it's freezing?
The unit is in quite open space in my backyard....

 

The freezing is caused by either a reduced airflow over the evaporator coils (which you may cure with a new filter) and you may also need to clean the coils, or, caused by low freon. For that, of course, you will need a service call from a pro.

 

OK. Thanks. I'll try a new filter. Freon was changed 2 months ago.

 

Why was that? Freon does not get old and ineffective. The only reason to change the freon is compressor burn introducing acid into the freon.

Did you have a leak or did someone do a sales job on you??

 

OK. Looks like they just made some money on me.

I asked them if there is a leak and they said no, freod just needs to be changed every 1-2 year....

Thanks for your help!

 

That's called fraud in my opinion. Refrigerant will last forever as long as it don't get contaminated. It would only need changed if your compressor had a burn out and was replaced or if it had non-condensables in it.

Did they actually say changed or charged ? If they claimed it had no leaks I would assume they told you changed. That's a new one on me.

 

The said it should be recharged.

Anyway, I've changed the air filter. But the unit is still freezing up.

There was no ice about 24 hours, but this morning I 've realized the air is not cold again, checked the outside unit and it's freezing.

Any other idea, what needs to be done?

Thank you!

 

More than likely you need to have the unit recharged - and the leak repaired.....

However - before you do that - check the evaporator coils inside the main unit. If they get dirty enough they can restrict airflow enough that the unit freezes up. I had the same problem during a basement remodel when the drywall dust (sanding) coated the coils enough to cause the freeze up. A thorough cleaning eliminated the issue.

 

Do you mean coild inside the outside unit? Yes, I cleaned them a couple days ago... So it did not help.... :-(