what causes outside a/c line to freeze.?

Question

units are mismatched tonage wise; 3.5 out/ 3 in
there may be a leak but leak detector did not respond by tech checking evaporator.
Thanks!

Answer 1

I am assuming your tech checked the charge while he was there, and that the problem is not the refrigerant charge.

The reason your mismatch in equipment is problematic is that your compressor is oversized for your evaporator coil. This means, it will be difficult to run enough warm air across the coil to keep the unit from freezing if there are any obstructions to air flow. Here are some areas to investigate:

Plugged or loaded filter (washable filters are notorious)
Collapsed, undersized, or obstructed return or supply vents
Plugged &/or moldy evaporator coil
Improper speed on blower wheel

Because of your tonnage mismatch, you must have adequate ducting for supply and return air. It will also be difficult to properly dehumidify the home. The cooler air coming from the super-cooled evaporator coil may lead to "shorrt-cycling" , and not allow sufficiant running time to dehumidify the home.

For optimum operation, make certain your evaporator coil is spotless, see if there is an easy way to "super-size" the return air duct and/or chamber, use 1" pleated filters, and change monthly.

Good luck and God bless you.

Answer 2

Could be low charge. But it's more likely an air-movement problem. Make sure your air filter is clean and check to see that your return air grills are clean and not blocked. Also your blowers vanes may be dirt caked. NOT a good match - if the out was 3 and the in was 3.5 it would be better. You say the tech checked the evaporator. He should have checked the entire system.

Answer 3

I have had a slow leak ever since the guy put mine in, and that was 13 years ago.

It only leaks an ounce or two, through out the Winter Season, and then, it makes my "inside" coil freeze up.

(I have learned, that if I switch off the power, yea, I forgot to a few times, it seems to abate the leak for a year or two).

I wish you well..

Jesse

Answer 4

A/C's don't last more than 5 years. If yours is beyond 5 years, you're lucky. Expect problems soon. Freezing on a system more than five years old is more than likely due to escaped refrigerant. The other common cause is reduced air flow. Keep all cold air outlets clear.

Answer 5

There could be several reasons. One could be a low charge of freon, two the evaporator of the air filter could be dirty, three a piece of insulation may have fallen off the inside of the evaporator and is restricting air flow, four, there could be moisture in the freon, five, there could be a kink in one of the copper lines, six, the compressor in the condensor could be weak.

I have seen them all. Good luck.

Answer 6

We are having the same problem, may need freeon or the motor is going bad. we have to get a new motor for ours.

Answer 7

either low on freon or the condenser (outside unit) is clogged up or the condenser fan not running

Answer 8

LACK OF FREON