Our central air keeps freezing...help!?

Question

We looked at the filter and its clean and all the vents are open but the pipes to the unit keep freezing. Any suggestions on what to do next?

Answer 1

the other two answers are correct plus you will need to check your a coil inside the furnace plenum for an air blockage.

Answer 2

It depends on if the evaporator is frosted up or the high side pipe or both the pipes or all three.

If the small high side pipe is frosting but not the evaporator you are likely low on refrigerant as it is expanding before it gets to the evaporator.

If it is all three you likely have a bad expansion valve and the refrigerant is flowing through it too fast.

If the evaporator is frosting up you have a sizing problem or still not enough air flow. I would clean the blower wheel next as most people forget to have those cleaned. A dirty blower moves much less air.

And I assume you are not using filters that are too restrictive or have over filtered with additional filters in the returns or vents along with the furnace/air handler.

Good luck.

It sounds like you have addressed the basic consumer maintenance.

Answer 3

HVAC Tech.:  A lack of air flowing across the evaporator coil can give you this problem,causes for this are blower fins filled with dirt, coil itself filled with dirt from being run with no filter or dirty filter.  additional cause might be loss of refrigerant charge. if the ice is on the outdoor unit , it could be over charged.

Answer 4

Although true that you could be low on refrigerant, I have found in my years of experience that a evaporator coil which is so plugged with crud,  the air cannot pass through therefore the heat will not transfer to the expanded refrigerant. This to causes freezes and a lot of other headaches. Check that first. If the coil and filter is clear call a technician.

And do it quickly before you slug your compressor.

Answer 5

You may be low on refrigerate, or the coils may be stopped up. A garden hose can flush the coils, but a tech needs to do the coolant.

Answer 6

Your refrigeration system is most likely low on refrigerant.

You'll have to call a repair technician

Answer 7

go to ace and get the cheap filters for a buck that allows more air flow but  if the line continues to freeze you need to fill it