I have a Samsung EH035CAV mini split that has worked great for three years. It is the slim concealed duct version with a wired controller / thermostat. A few weeks ago the unit was not running on a hot day, and the controller displayed an error code of 101, which is listed as a 1 minute time out communication error. It was working great one day and not at all the next.

My local reputable HVAC service has been working on this for over three weeks now, with no success. I was present during each visit and repair attempt.

First, they called Samsung tech support and we worked through a diagnostic process of checking line voltages, integrity of the communication wires, blinking LEDs, etc. Then we disconnected several things from the outside PCB and checked something. The Samsung tech said it was definitely the outside control board. The board was ordered.

A week later, the outside board arrived, we installed it, restarted the unit, and a minute later got the same error code.

He called Samsung tech support again, we went through another series of diagnostic processes, and the tech said it was definitely the inside control board. The board was ordered.

A week later, the inside board arrived, we installed it, restarted the unit, and a minute later got the same error code.

Both the local HVAC tech and I were getting more than a little perturbed at this point. He called Samsung tech support for the third time, and the guy immediately claimed it was because we forgot the "thermo-grease." It quickly became clear that he didn't know what he was talking about. After about 2 hours on the phone with him, and lots of back and forth until he understood what we were talking about, he stated that the problem was most likely a programming error on the NEW inside control board that we had just installed. He told us we had to order another inside board. He couldn't explain why or how he thought this, but insisted that was the problem and there was no way to test or verify this.

By this point in the ordeal, my local HVAC tech had also attempted to verify that Samsung would back their tech support and either accept returns of the boards that were apparently unnecessary, or refund us for the cost of the unnecessary or bad boards they had sent. Samsung and/or the distributor he was dealing with said they would not accept any returns and would not refund my money. I decided to stop at this point and try to figure out my options.

Apparently Samsung would like me to continue to buy and install new boards and hope the mini split magically starts to work again. My HVAC tech is stumped and not very willing to continue this process. They are suggesting that I give up on Samsung and buy a whole new Fujitsu system for several grand.

If you're still reading, thanks! I now have a non-working mini split with new indoor and outdoor main control boards, a large bill for non-existent repairs, and no idea where to go from here. Can anyone help me out?!

Notes: I'm a small time, tech savvy, remodeling carpenter. I ordered and installed this mini split myself to save money on my own home. I believe that makes me ineligible for their warranty. The unit is dated 2012, but I installed in 2013. Installation was simple and the unit worked perfectly for three years. I have some experience with electronics--I can test and replace capacitors, fix cracked solder joints, etc.

I understand you won't help me with DIY. I'm very willing to pay a professional who can fix it, but the ones I'm paying right now can't do that. Is there any way to run some more specific diagnostics on this unit to figure out the problem? Is there any way to, at a minimum, convince Samsung or the distributor to take back the parts that they told me I needed but which I apparently don't?

Any other helpful advice?

Thanks for your time,
Newton, Kansas