Can an A/C unit freezing up & then thawing cause a stain in the ceiling?

My home is only a year and a half old and I have 2 ceiling stains in my downstairs. My furnace is upstairs in a closet with a drain. When I noticed the first stain it was determined that the a/c unit had a leak so it was freezing up and thawing and with it thawing the water spilled out and caused the ceiling stain.





I now have another small stain and now the a/c tech said it is from it freezing up because I ran it when the temp was below 70 (we've had a couple of cool nights). I set the a/c way up high in the evening so I don't think it ran though. Is what he is telling me caused it correct? He also told me not to use good furnace filters (the more expensive ones that remove allergens) but to use the really cheap ones (that resemble steel wool somewhat). He said it runs more efficiently with the cheaper filter.





I appreciate any help you can give me in determining if what he said is correct because I know nothing about this.

Can an A/C unit freezing up %26amp; then thawing cause a stain in the ceiling?
he is partly correct about the cheep ac filters. But you should be able to run your ac when is below 70 outside. Is the guy that looked at your system the same guy that installed it? if so, call someone else. Just remember that your ac system HAS to be able to take in heat to run properly. I know it sounds funny but it is true.
Reply:He told the truth about the filters. the allergen type are so tightly woven air can't pass through easily and could cause the unit to work harder and deliver less cold. He might be snowing you about running the unit when outside temp is 70. The coil freezing should not cause moisture in the ceiling unless the drain for the pan was leaking. As the frost melts the drain should carry it out side. I think you have warm air from outside mixing with cold air inside and causing moisture. You may have to insulate the void the vent conduit is in.
Reply:I do not agree. Your unit wouldn't freeze up for running it below 70. It will run untill it satisfies the thermostat and it will shut off. The only way that the coil thawing could cause a stain would be if your drain is plugged and instead of draining it is overflowing. On the furnace filters,as long as you run the same thickness filter it will be fine no mater if its high effeciency or cheap.
Reply:it's freezing up? have you seen this yourself? there are good reasons why this happens, and running it when it's 70 outside is definitely NOT one of them.





get another AC person to look. it could have a clogged condensate drain, or low on gas, or dirty evaporator coil.
Reply:yes an a/c unit freezing up%26amp;thawing can cause a stain in the ceiling.some of your information i don't understand clearly.upstairs in your closet at the drain is the water draining some times something can block the pipe inside to cause the water to over flow.this should be checked out also is there a pan to keep excess water from leaking on the ceiling.if your low side tubing on the a\c unit is frosted up some one could have over charged the system with freion causing the condinsation to leak water on the ceiling things you should check out.it's hard to say any more i wish i could see the problm.
Reply:sounds like the drain, has spilled over,


get the person that installed it , to ex ten it out past ,your building,


your house is new. you should be covered,


for at least ,5 years


the cheaper filters due in fact work