Time for another disgruntled whirlpooo owner to weigh in. It's been like 5 minutes since you all heard that, eh?
I got this unit in 2004 and had no problems until winter of 08 (10 months ago). I am doubly unfortunate in not only owning a whirlygig water heater, but also an aqua-therm central heating unit! So, when theres no warm water, theres no warm *anything* in my house. Great, right?
So this story starts 10 months ago (feb of 08), on the coldest day of that winter, of course the water heater craps out on me after working almost nonstop to keep my house warm. It's dedication was admirable. I, of course, tried re-lighting it with mixed success and quickly called support to hope for a quick fix. Replacement parts were headed my way in a few days. Great, back to electric heaters and using the fireplace for me! They were gracious enough to send me a whole gas kit for the unit, including a new burner, valve, and related bits. I figured great, they must have gotten the design right by now since it was about 3 years since I bought the thing. I install the parts and the unit is up and running perfectly the rest of the winter.
So it would figure that this winter (oops, according to my calendar winter hasnt even started yet! i am in trouble!) the water heater craps out again. No pilot, same kind of problem as last year. Deja vu is swirling in my head as I call whirlpoo again, forking over another $15 for quick shipping of replacement parts. Back to the fireplace and electric heaters for me.
So, being an overly zealous tinkerer, I start troubleshooing the thing. The safety thermostat has continuity, the thermocouple has voltage, it seems like everything is hooked up right. On a dare, I shorted the thermostat connection and tried to light it. Flame! It ran OK until it got up to temp and the water thermostat shut it off, and then poof no pilot. It won't re-light either. Back to square 1.
So, I am no HVAC expert but I do know a little about mechanics and I got to thinking, what the heck is that little hexagonal shaped assembly that the thermocouple and the safety thermostat attach to? Is it a fail-shut control of some sort for the pilot gas valve?
Anyway, in summary, love the site, hate the whirlpool. Thanks to everyone who posted good info!