Let's see, when did we buy this water heater? Looks like April, 2003. ~10 years ago.
It's been a bit of a saga.
This is our tankless, continuous, on-demand water heater, a Seisco RA-28. When it works, (which it has just fine except when it has sprung leaks) it works well. The problem has been the leaks. The plastic has been prone to hairline cracks after 3 or so years. And the circuit board is not protected from leaks. When it's not working it doesn't just not work a little. You need to shut it off to protect it. And the danged thing cost $600+ in 2003, and it's $800- $1000 to replace today.
The plastic is something Microtherm developed with DuPont specifically for this application. It's a special kind of nylon that is supposed to stand up to the rapid temperature fluctuations inherent in a unit like this. But a while back they apparently had some quality control problems with the plastic. It was being formed outside the country and imported. Last I talked to them they said they built their own manufacturing facility right in their back yard in Texas and that those problems had gone away.
We had a leak in May 2006, Jan 2007, and I want to say again in 2009, when I replaced both two-cylinder chambers with new plastic.
The worst of it was in February of 2007 (read, COLD in Missouri), when we were without hot water for about three weeks. We'd had a leak, I got a new part, installed it, and one ... single ... solitary drip dripped onto the circuit board and *BANG*.. so I had to order a new circuit board.
Now the service department was very responsive, and shipped stuff fast ... except the circuit board came in four days later than expected (not sure why that was), and warrantied the parts. I just paid for shipping on most of it. They even put me in their database as a tech, so I get to real live people who know stuff when I call. As of 2007, I was the only guy within 150 miles who had any experience with them.
When I replaced the circuit board, I slipped a Ziplock bag around it and screwed it back on to it's mounting point, with small holes to run the wires through ... to help protect it against future leaks.
Well last Friday I got a call at work. Vicki said there was a strange buzzing noise coming from the water heater. I knew right away. It was the leak sensor alarm. Dashed home, and there was a fine mist spraying out of the output pipe, which, other than the input pipe which isn't subject to the wild temperature fluctuations the rest of the plastic is subject to -- is probably the oldest part in the unit. Hairline crack. Just like the previous problems I'd had.
I tried patching it with Sugru, but it didn't stick well enough to the plastic to stop the leak. I ended up wrapping a washcloth around the output pipe to catch the leak and force it to drip to the floor and into the floor drain in the furnace room instead of spraying on the wall. Or the circuit board. But I leave it turned off except for when we need it. Called Seisco and ordered a new output pipe. $50 plus shipping. Ouch. Since then the leak has gotten much worse, but it's still controlled. I'm wondering why that output pipe can't be copper.
I've been thinking about just having some parts laying around so I can fix things as they come up with minimal outage time, but I haven't ordered parts. So I thought ... hey, let's just see if there are any parts, or maybe used units out there.
Checked Ebay. A store in Arizona had had five NEW RA-28's, and was clearancing them out for half price. $400. I bit the bullet and ordered the second to last one.
I've been turning the water heater on only when needed, and even shutting the water to it off.
This morning, the water didn't get very hot. There is water leaking onto the output temperature sensor wire on cylinder 4 (or the input temperature wire on the output pipe. Don't know if that's the problem. But clearly it's not a happy unit. The error code on the unit is "135", which the trouble-shooting manual is reserved for "future use", but also says bad heating element in circuit #2.
So I'll put the new pipe in when it comes, hopefully today. When the new unit comes next week, I'll install it and keep the old one for parts. That way I should have a new unit under manufacturer warranty, to boot.
So ... it hasn't been as stable as a traditional tank heater, and it's certainly been more expensive. However, it is the best solution for our house. We don't really have room for a traditional water heater anywhere, and we do like the continuous hot water. It also saves on energy. Hopefully this new one will have well-formed plastic and last us many years.