Why do cooling coils keep freezing over?
Melting iced-over coils with a heat gun fails to fix the problem because they quickly refreeze even worse within a day. This leaves the unit struggling to reach its temperature set point, trapping owners with a system that won't stay cold and leaving them unsure where to go from there.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Turn off the unit to allow it to thaw and change the return air filter.
- 2Using a heat gun to melt ice on the coils
- 3Checking and clearing the drain hole with warm water
- 4Replacing the appliance due to high repair costs
- 5Turning the unit off to clear the frost and restarting it
- 6Bubble testing line set connections for leaks
- 7Weighing out the charge from a vacuum
- 8Clearing the condensate line with warm water and vinegar
- 9Installing a DIY p-trap
- 10Switching air filter types
- 11Running the fan to thaw the system
- 12Leaving the door open to increase airflow
- 13Checking and replacing air filters
- 14Calling shops from the nearest town to find technicians willing to travel to rural areas
- 15Switching to a different HVAC company instead of calling the original installers
- 16Contacting the manufacturer for assistance or a manufacturer's representative
- 17Requesting a static pressure test or complete load calculation
- 18letting the system thaw
- 19cleaning the outside unit
- 20checking if the blower fan is blowing and vents are open
- 21researching potential refrigerant leaks and warranties
- 22adding refrigerant charge
- 23checking piston and orifice sizing
- 24inspecting for restrictions
- 25Removing air filters to improve airflow
- 26Adding refrigerant and stop-leak products
- 27Getting quotes for entire system replacements
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“AC stopped cooling early last week. HVAC company added refrigerant (1 pound, I think?) and some “stop-leak” ($450 all told). A week later it froze as in the photo. Same company came out and said the stop-leak must not have been enough. Also, they couldn't just repair it, but I needed a whole new system because the refrigerant has been phased out (R-410A). They quoted $9,800 for a heat-pump and evaporator coil and everything.”source ↗
“Our freezer stopped getting to freezing temperatures a few days ago. It is a little cold, but not freezing.”source ↗
“I opened the back panel of inside the freezer and the first part of the coils was frozen over. I used a heat gun and melted it and it did not fix the issue. I checked the coils again today and it is way more frozen over than it was the other day.”source ↗
“I'm not sure where to go from here.”source ↗
“Got home and my unit was struggling to meet SP.”source ↗
“Decided to go outside and check out my condenser and found it froze up.”source ↗
“One year ago we had a new ac installed, 10k it cost and every month to every other month we’ve had technicians come out because the ac randomly stops working because the unit freezes.”source ↗
“Back in july our ac started leaking like crazy, with a brand new filter I had installed the weekend before.”source ↗
“It starts leaking, again, life got super busy so we just delt with the water for 3 weeks, we finally get a guy to come look at it, he says the drain pan is cracked”source ↗
“Now it's freezing up every other day”source ↗
“If anyone has any ideas I'd greatly appreciate it, we want to call another company but we don't have hundreds to spend on dingosis calls to hear "well it's probably the pan give us 2k"”source ↗
“The system has frozen up multiple times and has struggled to cool properly.”source ↗
“Went outside and saw that the liquid and suction line were frozen over.”source ↗
“Liquid line is frozen up again.”source ↗
“ANY ideas or points to check when I go out tomorrow would be SUPER appreciated.”source ↗
“If the ducking airflow not exactly air tight would it be freezing like seen in the picture please advise me.”source ↗
“The problem is it freezes instantly as soon as I turn it on, it starts freezing instantly from the inside unit it doesn’t freeze from the outside unit”source ↗
“The problem is I live in a really rule area like inside the woods and it’s hard for me to find somebody that’s willing to come out to the place look at it”source ↗
“The outside unit itself, the copper lines, and the cooling coils inside all froze.”source ↗
Where this came up
People with this problem also raised
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- 2HVAC system stops taking refrigerant during charging
- 2How to reach a frozen evaporator coil blocked by refrigerant lines