Question Daikin Minisplit AC Unit Can't Keep Up

[iiSlashr]

I've had a Daikin minisplit unit in my room for a year or so, and it's been having constant issues keeping up any time it is actually warm outside. It's rated higher than the size of my room, and sometimes it keeps up just fine, but other times it will completely flop. Currently, it's in the 80s where I live, and with the unit turned to 68 degrees on max fan speed 24/7 it can't keep it down, with temps reaching 82 in the afternoons/evenings frequently and not coming back down into the mid/low 70s until well past midnight. The people who installed it have been out a half dozen times to try and repair it, have essentially replaced every part imaginable, and finally came to the conclusion that a cheap microwave was putting off RF interference and basically making it do random actions for no reason. I moved the microwave about 20 feet away, and for the first couple of days it was back to how it was when it was installed, keeping it at the set temperature easily and spending most of the time turned off or on very low fan speed. Recently, it's begun getting up to 82 again, regardless of the setting. The air blowing from the unit is barely cool to the touch no matter what it's set at. Does anyone know of any common issues I can troubleshoot without having to get the techs out to tell me there's nothing wrong with it again? The model number is FTX12AXVJU.

 

[hotaru.hino]

If a cheap microwave was capable of putting enough RF interference to mess with the minimsplit, it'd affect more electronics than the minisplit.

Now I'm not an expert on AC units or whatever (and really this isn't the place to go looking for that), but my money's on there being an issue with the refrigerant part. Either that there's not enough, there's a leak, or something else.

 

[Ralston18]

This model?

https://heatandcool.com/products/12...r-conditioner-heat-pump-system-230-volt-11649

What are the dimensions of your room?

How is power being provided?

 

[iiSlashr]

This model?

https://heatandcool.com/products/12...r-conditioner-heat-pump-system-230-volt-11649

What are the dimensions of your room?

How is power being provided?

Yes, that model. My room is a bit strange because it's got slanted ceilings since it's a partial second floor, but if I had to ballpark it I'd say maybe 30x15 feet give or take. I'm not sure how the power's being provided, it's got its own breaker and that's about all I know in that area.

 

[Ralston18]

Interesting.

The unit specs indicate 230 volts so that could explain the unit having its' own breaker. Versus being plugged into a wall outlet.

Another thought is the unit size. 12,000 BTUs.

There are online calculators to help size window air conditioners. The manufacturer may even have a calculator.

For the most part you answer a few questions about the space to be cooled and the calculator provides the appropriate BTU sizing.

For example:

https://www.calculator.net/btu-calculator.html

Find two or three other calculators and look for some concensus on the BTU cooling requirements.

What do you come up with?