No Filter

barnbuilder1

What are all the bad things that can happen if a filter is not used in a central air system? I'm having this problem at my rent house. Thanks.

BigReds

You plug the evaporator with dirt thats a no no. Causes your systems efficiency to drop a lot, also your unit will constantly trip. Shortening your systems life span.

naptown CR

First you will get dirt on the evaporator coil and efficiency will drop
Then the coils will freeze up blocking all airflow and the unit runs continuously but no cooling.
worst case scenario is liquid refrigerant gets back to the compressor and freezes and snaps a reed valve = new compressor

barnbuilder1

Thanks for your prompt answer, I had told renters that I would clean filter but she said they would do it, should have checked sooner. Anyway now the framework for filter is missing, may have to fabricate one. I was afraid of your answer, I knew that dirt would collect on A-coil and make system work harder but didn't know about reed valve.

What is the best way to clean A coil?

trptman

I don't think you want dust bunnies caked on the motor that runs your blower, or caked on the printed circuit board (furnace control board).
It's bad to run with a plugged filter and it's bad to run with no filter.