Why is my evaporator coil icing over?
Dense MERV 12 filters can load up fast with dogs and smoke, causing rapid airflow restrictions that freeze the evaporator coil and refrigerant lines solid. This causes the unit to run for hours without reaching the target temperature while spitting out water.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1cleaning air filters
- 2clearing clogged condensate drain lines
- 3adjusting thermostat temperature and fan speed
- 4Switching to a lower MERV rating filter like MERV 8 or MERV 5
- 5Upgrading to a 4-inch media cabinet filter to increase surface area
- 6Raising the thermostat temperature set point to 68 degrees or higher
- 7Using a separate box fan with a high-MERV filter for air purification
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“The 1" MERV 12s are dense and they load up fast with dogs and smoke, so restriction climbs quick even at 2 months.”source ↗
“Unit worked great for 16 months but now it’s icing over and spitting out tiny amounts of water.”source ↗
“The evaporator coil started icing over about six weeks ago after running the TCL evaporator cleaning mode.”source ↗
“I turned it back on and at 61F and full fan speed, it iced up within 5 min.”source ↗
“ever since July this year it's been having trouble keeping up. It'll run for 3, 5, 8, sometimes 11 hours straight and not quite get the temp down to set.”source ↗
“Before this week I never caught one, but this time the line was frozen all the way from the evap coil to the compressor.”source ↗
Where this came up
People with this problem also raised
- 2How to reach a frozen evaporator coil blocked by refrigerant lines
- 6Should I replace my HVAC system if the evaporator coil leaks?
- 3Why is my fridge fan making a dull noise and rattling?
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- 2Why is my converted freezer accumulating so much water inside?
- 2Is air conditioner condensation normal or a leak?