A/C Question

[DonTx]

I was looking at this 5 ton A/C today and it wasn't getting as cool as I thought it should. Of course the Seller said they'd just had it serviced, no invoices though, imagine that!

Anyhow, I had a little extra time so I took the front of the Evap. coil housing off so I could see it. Lots of rust at the lower section and some up the sides of the "A". I noted condensation about half way up the "A" on the ends of the loops.

Seems to me that I heard once that meant the unit was low on coolant. Also, there was what looked like an expansion valve to the front of the cabinet. Between the cabinet and valve, the copper was cold and condensating like crazy. On the other side, the copper line was luke warm or even at the same temp as the attic.

What does this mean?

The temperature at the Return Air was around 70 degrees and the temp at the supply registers was between 60 - 63 degrees. The outside temp was about 75 to 80 with some pretty good humidity thrown in for good measure.

Donald

[allspec33351]

Donald

You get a alot on condensation in the attic. Because of temperture differentials.

Based on what you said my guess would be you have a refrigerant leak in the system.

Captain night

[a46geo]

Don,

Its an older unit, as Mitch says, low charge would be my guess too. With out measuring the temp at both sides of the coil (not the registers) and checking the operating pressure, we are only guessing.

George

[Terence McCann]

Hello Don:

Typically if the evaporator or suction line sweats that's ok, the condensation your seeing is why there is a condensate drain line off the evaporator coil. If the suction line was luke warm leaving the evap that would be a problem depending on how long the unit was running. I would be more suspect seeing frost. Frost/ice could mean a leak, lack of air flow etc.

How long did you leave the unit run before taking supply/return temps?

[DonTx]

Thanks everyone, I wrote it up as insufficient cooling and rust on the lower section of the evaporator coil. I also had some leaks around the edges of the evap coil housing and at some duct connections. I then stated it needed further evaluation by a qualified and licensed HVAC contractor and all necessary repairs made.

Terence

The unit had been running between 30 minutes to an hour. I thought it was odd that only have the A coil had condensation on it while the top half did not.

Sure wish some one could come out with a troubleshooting chart with general rules of thumbs for evaluating A/C's.

Donald