It sure seemed like there were several repairs that had to be made this summer. I had issues with the RV water supply, with the pool, with the spa, and also with the air conditioner. I installed the Mr. Cool one ton unit in 2019 after several failed experiments with a chiller to cool the radiant floor. I also had purchased a used mini-split that was 9000 btu, and I worked to install that one but could not get the lines to hold a vacuum. The DIY mini-split comes with pre-charged lines so the installation does not require pumping the system into a vacuum and then charging with refrigerant. It is all completely charged and the connections don’t require brazing or flare fittings.
Last summer it appeared that there were issues with the Mr. Cool. It appeared that the air was not being cooled as much as it had been. I cleaned the filters but there was not much else I could do. I hired an HVAC pro to look at it and he determined that the condensate line’s path to the washer stand pipe was backing up because some of the line dipped and didn’t flow continually downward. Part of the paint on the wall was even blistered from the water dripping out of the indoor unit. He measured the coolant and said that it appears to be fully charged. So he installed a condensate pump to pump the water out of the conditioner. He also applied a special cleaner to the filters and we didn’t have more issues for the rest of the summer.
This year we started having problems again with the water dripping from the indoor unit. It appears that the condensate pump only lasted a year. It was expensive too at about $250. So we noticed a significant drop in cooling. I again cleaned the filters washing them in Dawn dishwater and letting them dry outside. I also found condensate leaking all over the attic with the floor so wet it was turning black. That was an unpleasant surprise. I dried all of that out and checked for leaks to the pump and then made sure it was level and feeding down from the unit. All to no avail and then the unit went into an error mode.
The Mr Cool support was fantastic. They had me do an electrical test on the outside unit and the results determined that the problem was the control board inside. They sent me a replacement for the cost of the postage. There were instructions online and a video about how to open the evaporator unit and remove the cover and the old board. I had to stand up on the refrigerator which was actually better than a ladder would have been. I removed the control unit and took lots of photos of the wiring that I was removing.
Then there was the challenge of fitting it all back together. In fact it reminded me of the cartoon of the long equation on a chalkboard with “A miracle happens here” written in the middle. Because the video showed some of what had to happen and then left out details when it came to reassembly, which is NOT the same as disassembly.
I was able to change the board and replace the system but had the same issue with water backing up so I disconnected the wiring for the pump I double checked that the inside wiring was correct.
Then I let the condensate drip into a bucket in the attic, emptying it each day before I turned the air back on. The unit then started to give us nice cold air again. Lovely but it has not lasted. It could be that the filters need to be cleaned again, but I fear it is something more complex given the new control board and removing the condensate pump .
The differential between incoming and outgoing cooled air is supposed to be about 20º. I have a temperature measure that shows 82 degrees going in and about 75 coming out. When it is operating correctly its 82 going in and 64 coming out. That cools the room during the day.
So this issue probably requires that I call the company again for help troubleshooting. It will be interesting to see if this can be fixed again.