my 2 year old unit it freezing after it’s been running about 10 minutes. I turned the unit off all last night. This morning I took a look at it outside, then went back in, turned it on, sat by the vent. It was blowing cold air for about 10 minutes and then stopped. I immediately turned it off, went outside to check for any visible signs of ice on the copper lines and or condenser below the outside fan. No signs of freezing. I did see some sweating on the copper lines though.

While standing at the unit, I turned the “Fan” (blower) on the ecobee phone app. From the area where the control board is, I heard a click, then nothing for a few seconds, and then another click. The click sounded like a relay. I didn’t notice any humming or other noises, though at the time, the unit was put together.

I’ve done a lot of reading and based on everything, I’m thinking the problem could be a bad capacitor or contactor.

Does it like I’m on the right track here?

Here are a handful of various pictures: freezing, blower motor, control board, schematics, etc. https://i.sstatic.net/VPDuC.jpg

Thank you for anyone able to provide help! Some things in life are simple fixes, if we spend the time to better understand how they work. If I need an hvac technician, I’m always willing to give up my own bootleg technicians license. :-)


2 Answers 2


There could be multiple issues, low Freon levels is one that can cause a low Freon pressure shutdown , this usually takes a specific amount of time based on the ambient temperature once the system has compressed the high pressure side and the suction side doesn’t have enough pressure automatic system shutdown, the second can be an iced up evaporator coil causing high back pressure as Jim said with the air handler motor tripping its thermal overload, once it cools down it will restart if the unit is still turned on. You need to open the inside unit (air handler) and see if the coil is iced up. If iced up you will need a leak check and recharge. 2 years old there is a leak that needs to be fixed prior to recharging or you will be recharging again in 2 years or less. If the coil is not iced up spin the motor you may have a bad bearing that is causing the motor to overload and trip it’s thermal overload, these are the main problems I see and would be my first checks, a cap going bad in 2 years is possible but they usually last much longer and would trip out sooner (just a minute or 2) if a start cap.


The freezing that occurs is in the evaporator coil inside the air handler. Usually this is low refrigerant charge causing the evaporator temperature to go below freezing resulting in an impenetrable mass of ice building up on the evaporator coils. The blower would then be under high back pressure. There may be a safety system that shuts off the blower motor if the back pressure is too high.

If the coil is allowed to thaw, then the unit will work for a short time before the ice builds up again. I suggest you get a competent tech to test your unit.

  • Thanks for the insight! I just replaced the whole unit 2 years ago and it hasn’t even made it through 2 full summers. Is it normal for a unit that new to be charged? And if not, could it be a possible sign of poor installation? I’m going to call a tech out here. Not sure if I should call out the one that installed the unit. I just hate trying to find good honest people with quality work in these types of industries.
    – getUser
    Jun 21, 2019 at 17:47

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