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Fixing Things: UV Filter

We filter the bejeezus out of our water (see Water Filtration System). I think it’s because we were living in Milwaukee, WI during the 1993 cryptosporidium outbreak, the largest documented waterborne disease outbreak in US history.

Our UV (Ultra Violet) filter is a key part of our RV’s water purification setup. Not only does our UV filter disinfect water, it also stops water system algae outbreaks (see The Green Stuff under Fixin’ Stuff).

Our UV Filter (click on drawing to enlarge)


UV Light Bulb

The “heart” of a UV filter is the UV light itself. The ultraviolet radiation from a UV light effectively sterilizes water.

However, since the UV bulb gradually dims over time, it must be replaced. In our case that’s once a year. Our Sterilight UV system has a Controller that notifies us when the UV light is failing by flashing “A3”.

So when our Controller started flashing “A3” recently, I replaced the UV bulb and the glass sleeve that surrounds the bulb. Easy peasy, right?

Not this time.

This time our Controller kept flashing “A3” and other error codes. Bad mojo.

I knew what this meant — the Controller had gone south. Since we first installed our UV system, the Controller had failed once before about 3 years ago.

Because a new Controller costs over $300, replacing it was not high on my list of things to buy.

Blue Screen of Death


So I played a hunch.

What if the Controller was still sending power to the UV light? However, since the UV light is sealed up, how could I tell if it’s working?


Does it feel warm?


Because we weren’t running water, a functioning UV bulb will warm up its enclosure. So I just “laid hands” on the enclosure — it was warm. Pretty complex test methodology, eh?

I’ll be saving some money for a while and just keep feeling up our UV tank.