Why do cooling coils keep freezing over?

“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 ↗

“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 ↗

“Now nothing will start up. Turning on the fan does nothing. Turning on heat does nothing. Turning on AC does nothing.”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 ↗

“That would be in the crawl space I'm assuming somewhere between the unit and the little pump sitting on the ground covered in black widow webs? I will have to check when I get home.”source ↗

“Maybe once or twice a year the coil in my air handler freezes over.”source ↗

“I have maintenance contract with a company every 6 months and they don't find any issues.”source ↗

“Hello! I’m renting a house in Houston and have been having problems all summer with the house not cooling to the desired temperature.”source ↗

“Since then, the house will stay between 79-81 which isn’t even fixed completely.”source ↗

“We noticed that one of the pipes of the AC outside unit was frozen so we had people come out...”source ↗

“I sprayed the evaporator coils with the Simple Green cleaner, but that didn’t seem to make a difference in the temperature.”source ↗

“I had to open up a hole right before the horizontal slab evaporator coil to access the coils.”source ↗

“Any suggestions?”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 ↗