Dehumidifier repair
 

Over the weekend I acquired a new to me dehumidifier. A friend had recently replaced this one with another since it stopped working and asked if I wanted it. He knew that my old one had taken a dump and I was considering replacing mine. So, after checking that I could get parts for it still, I accepted his offer.

Here is the unit:

http://ecorenovator.org/forum/attach...1&d=1479747618



I was very happy to see it is a lot more efficient than the current old one that I am running. The old one is rated for 1.15 liters per kwh where as this one is rated for 1.8 liters per kwh, a huge 56% increase in efficiency.

http://ecorenovator.org/forum/attach...1&d=1479747618



So, I tested the unit by plugging it in. It turned on and the fan kicked on right away. I was able to mess with it and it seemed to be working correctly. I turned down the humidity rating below what the room was at, and the compressor kicked on. So, I'm wondering what the heck is the problem? It seems to work just fine. Well, after about a minute of running, it just dies. Everything goes blank on it. It won't power on at all.

So, next step is the tear down. I moved it into the other room, plugged it in, again nothing. I removed the panels, and then tried plugging it in again and it powers back up. Odd. So, now I start wiggling wires. It now cuts in and out, so I know I have a short. Woohoo, those are pretty easy to fix!

http://ecorenovator.org/forum/attach...1&d=1479747618



So, I start wiggling more wires until I can hear the zap-zap sound consistently when I wiggle it. It seems to be coming from a component on the circuit board.

http://ecorenovator.org/forum/attach...1&d=1479747618



Lastly, I flipped the board upside down, turned the lights off and wiggled things again. Now it was super obvious where the issue was.

I heated up the soldering iron, put some flux on it, and fixed the bad joint. I plugged it in and it seemed to work just fine. The compressor ran for a while without kicking out and it ran all night in my basement.

http://ecorenovator.org/forum/attach...1&d=1479747618



So, this was a great find and an easy fix!

I do have a few concerns I could use some help with though. First, the solder on the board did not melt easily. I did end up adding more solder to the joint and the two did not seem to mix well. I'm a bit concerned about the integrity of the repaired joint.

Second, the dehumidifier seems to run the fan continuously. This does not seem right. It is energy star rated so I assume it would shut the fan off when its not needed. However, as soon as you plug this thing in the fan immediately kicks on. When I went to check it out this morning, it was still blowing. I didn't check to see if the compressor was on or not. I unplugged it because it didn't even need to be running in the first place, I just wanted to make sure it wouldn't die on me overnight.

Thoughts?

The solder on that production board is almost certainly lead-free. The problem with mixing the two is that it could cause the new solder mix to be brittle and prone to cracking putting you right back to where you were. It would probably be best to wick away ALL of the older solder from that joint and resolder it with leaded. As for the fan, I would check for a welded contact on a fan control relay. If it was arcing and sparking elsewhere, it could have caused some issues elsewhere. This of course is presuming that the fan ISN"T supposed to be on all of the time.

I really like the old "60/40" solder that is a lead/tin mixture. Works well with almost all repairs.

Still have several rolls of it in different diameters. Can you buy this 60/40 now?




Steve

Yep, no problem buying 60/40. The issue is with production parts needing to be RoHS compliant, home-gamers are free to use whatever they want, and 60/40 is definitely the way to go. Lead-free solder is awful to work with.