We just got back a few days ago from Barthing it for a week. The 1st night out, when I tried to turn on the hotwater heater it ran for a few minutes then shutoff... Of course it was dark out by then and with a flashlight I could see a coil on the electronic module was all black and sooty. Grrr, no wonder they sell so many of those aftermarket modules! So in a few days we finally get to some friends home in Northern WA. and get baths and re-wash all the dishes with hot water... Am I upset with Atwood Waterheaters or what? More Grrrrrr!! Now we're back home and I've pulled the thing apart and couldn't find anything really wrong except the "in-line thermal cut off" is burned out, and when I bypass it and the W/H lites flames come out of the slide air shutter and the whole thing is one big fireball! I take everything apart.... nothing! Look down one side of the burner tube, then the other side, more nothing. Next, I shove a rag through the flue... nothing, well, lots of soot! More Grrrr! Finally, as there is nothing left to do, I stuff a piece of paper towel through the burner tube and as the towel comes around the 90 deg. bend there's a silky white spider web stuck to it! When I try it this time everthing is back to normal and works as it should. Lesson learned: Never run your W/H without that "In-line Thermal Cut Out" (Without it our Barth could have burned up) and just looking into an aluminium tube with a 90 deg. bend in it doesn't always work, spiders are a sneaky lot.
Cheers, "Lucky John"

My next door neighbor is a pool man, and he loves spiders. They provide him with a lot of work the way they get into pool heater burners.

I saw on TV that mint extract keeps spiders away. We haven't tried it yet, but it might be something to try. They suggest putting mint on cotton balls and placing in cabinets and closets.