Tuesday, December 3, 2013

Mysterious Water Damage to Control Board

I have a control system that is mounted outdoors on a wall in a standard metal power center -- just like hundreds of other control systems (Jandy Aqualink, Pentair EasyTouch, and Goldline.) But, for some reason, this one is getting water inside the power center and the water always damages the same spot on the board. You can see a hard water trace on the back of the board where it runs down.

So how does the water get in to a sealed power center that is made to be mounted outdoors? Well, first I thought that it must be coming in past the weather stripping on the door. I replaced that. Next, when that didn't work, I tapped up the gap between the top of the box and the removable front service panel, but the water still came in.

Finally, I think I found a clue:
Look closely at the point where the outside covering has been stripped off of this temperature sensor wire. See the calcium / hard water deposits here? This is the temperature sensor wire for the solar panels. The other end of this wire is up on a second story roof. Evidently, water seeps into the upper end of the wire, drains down the inside and exits here where the outside covering has been stripped off to allow connection to the control board. Since the water is traveling inside the wire, it makes no difference that the wire drops lower than the power center and then goes up. (If the water was dripping down the outside of the wire this would prevent water from going inside).

My solution? I decided to allow the water an alternative outlet besides where it connects to the board. To do this, I stripped some of the covering off (to allow it to escape) and then bent the wire into a U shape and poked it down into a hole that exits the control panel at the bottom. This way, the water should drip outside the power center.