Split-system A/C units, like toaster ovens, might get disgustingly dirty before they actually wear out.
Now that the split-system A/C unit is running in the studio, I decided to attack the one in the garage that is eight years old and recently started throwing an "E1" error code. Documentation that came with the unit is scant - the only thing it says it to "call for service" if you get an error code.
The unit has had it share of small problems. The display (for temperature setting) is missing a leg on the LED display, so "72" and looks like "73" sort of. Also the small stepper motor that moves the distribution vane back and forth (and neatly closes up when shut off) died and the vane stays in one position.
The good news about that is a whole new display board is only $25 and an easy, one-screw installation. The stepper motor is only $6.95. So some parts are available - from Midea - and cheap, too!
But the main control boards (inside and out) are like $150 each or "NLA", along with something called a "reactor" which is NLA. A new unit (like the one I just bought for the studio) can be had for about $700 delivered. So it obviously isn't worth "throwing parts" at an eight-year-old unit, even if I expected a longer lifespan out of this unit.
I could not find the exact service manual for the MCHS-12AVH1 unit, although Midea has some manuals for similar units (there are hundreds of variations, based on capacity, voltage, country of use, refrigerant, etc.). This unit is 110V, 15A, R-410a, 12,000 BTU. It is similar to the one I installed in Mark's studio except that unit is rated for 20A (obviously less efficient).
I find the diagnostic page for a similar unit and the process for diagnosing an E1 code is as follows:
As you can see, the problem is either in the wiring, or the inside and outside PCBs are faulty. I presume the wiring is OK (although I will run a jumper wire around and see if that fixes the problem - I have plenty of control wire left over from the previous install). But I doubt it - wires don't just decide to disconnect themselves. The other two "solutions" are to replace the indoor or outdoor control units. (I am not getting the +/- 25V on the signal wire).
I suspect it is the outside control board, as the inside unit seems to work OK in fan-only mode. The outside unit made a frightening "pop" noise when I turned on the power. The inside control board is NLA anyway. Do I replace the outside control board and hope I didn't throw $150 away? Or just buy anew.
I noticed there was detritus on my workbench under the unit. It looked like mouse poop. Were mice living in the unit? That would explain a lot - but where would they be living? Turns out, they weren't. It was just eight years of debris accumulating inside the unit. I had cleaned the filters regularly and flushed the condensate pan periodicaly with hot water and soap. But the fan - a long cylindrical deal - was covered with what appeared to be black fur - mildew and dirt, I guess.
I tried cleaning it off with a soft brush and black dots of filth rained down on me. I then tried a spray bottle with soap solution. with similar results. Finally, out of frustration, I used a garden hose - after laying down some old towels to catch the water and debris.. Little black dots of filth rained down on me, yet again.
Here is a picture of the first round of black plague (I had to stop to vacuum this up, several times):
Ugh, this is worse than a toaster oven! Little black chunks of debris everywhere!
I suspect the problem is related to the fact it is in the garage and exposed to a lot of dust and debris, as well as hot, humid air, whenever the garage door is opened. The unit in Mark's studio, with all that clay dust and glaze, will no doubt have similar problems - the window units not only had rusted out, but their guts were filled with dried-on clay dust, which I discovered only after taking them apart.
I finally got all the detritus cleaned out of the fan, cleaned the drain pan and coils, and flushed out the condensate line. It was pretty bad. And do to all of this, I had to remove the vane and diffusers, as well as the entire cover (which has eight snaps and as many screws) to expose the "guts" of the unit. It didn't solve the problem, of course, but illustrated to me that these things need to be cleaned regularly - like a toaster oven - or they get gross. Legionnaires' disease anyone?
But speaking of toaster ovens, I took the thing apart (again) and removed the rotary switch which I then disassembled. The main power contact wasn't making contact and had signs of being overheated. Poor design or defective switch? But I was able to pull a part number off it and found the same switch online - although with a different shaft (the shafts appear to be interchangeable). It was only $13 by China Post, so we should see it by August.
If that unit can be repaired, we'd have four toaster ovens! (someone died and left us theirs - the heirs were going to throw it out it was so gross, but Dollar Tree oven cleaner to the rescue!).
Yes, it is possible to fix things, provided you (a) have the skills, (b) have the tools, and (c) have a source of inexpensive replacement parts. Usually one or all three are deal-killers. There is always (d) your time is not as valuable as the cost of replacing the unit. Don't forget (e) - bothering to fix an end-of-life product.
Spending time repairing a $59 toaster oven is sort of pointless, but if I do it, it will be for the experience, not to save money. Spending time and money repairing an air conditioner that has most of its life behind it, is probably pointless too. But I'll check the wiring before I throw it away. I already checked the charge level (OK) so that is not the problem.
Toaster ovens should last more than eight months, though. Air conditioners should last longer than eight years! Should, anyway.
FWIW.
UPDATE: I disconnected the control wiring from the outdoor unit to the indoor unit and ran a jumper wire in its place. I had so much wire left over from the previous install that I was able to run it through the doorway. The same thing happened, the E1 error occurred.
So I believe the outside control board is bad. I disassembled the outside unit and it was filled with filth and the control board looks like it's fried. I ended up just buying a new unit to replace the whole thing. I also bought the wall bracket to keep the outside unit off the ground.
A friend of mine is installing a split-system unit in his garage and asked if I would do it for him. I explained to him that it was a difficult process and he withdrew the suggestion.
His local HVAC guy wants $1,500 to do the entire install (not including the cost of the unit itself which was about $1,000) which, from my perspective, is pretty cheap given that their hourly rate is over $100 an hour and it can take the whole day to install one of these, especially if you have to drill holes through brick walls.
He plans on using a wall mount and also building a small roof over the top of the unit to keep the rain out. Of course, you have to follow the instructions in the manual to make sure the roof is far enough away from the unit to insure proper air circulation.
On our conventional air conditioning system, we put a diverter on the roof to keep the rainwater from rushing into the unit. One of the technicians also suggested putting a fine chicken wire over the top to keep the pine needles out. I noticed in Florida people have plastic covers look like garbage can lids, that are attached with a tether. When the fan turns on, it blows the cover up allowing air to go through and then when the fan shuts off the cover flops down keeping debris and dirt out of the unit.
Some people report replacing their air conditioners here by the ocean every 5 years or so which seems kind of extreme to me. I notice our unit which is 5 years old is already showing signs of rust on the fan motor. I periodically remove the top and fan and vacuum out the inside of the unit. The next time I do that I'm going to give the motor a coat of black paint.
