Our hot water tank has been acting strange. We just bought this house in September and the tank is from 1996. Somedays the water is nice and hot for 3 straight showers and somedays it's luke warm for the first shower and everybody else is out of luck. It is a gas tank. I've checked it when the problem first started to make sure the pilot was lit and it was and it was in the process of heating the tank. Suppose it's a thermocouple issue or should I go ahead and replace the whole unit?

16 years old? With the changes in energy efficiency, you'd probably be well-served by just replacing it.

That said, has the tank been flushed for sediment since you bought the place? Might be worth doing as preventative maintenance if nothing else.

What he said Definitely

Good point, I didn't think about that. I'll flush it over the holiday and see if that helps. If not I'll go ahead and replace. I was hoping not to have to replace anything major for another year or so due to the amount of foundation work we are about to start.

Oh, do I feel your pain there.

We bought our house in summer 2009, with the knowledge that the roof was going to need some attention in the next couple years. It started leaking in late fall of 2009. I patched it for the winter and we re-roofed in summer 2010. Re-did the downstairs bathroom thanks to a water leak in spring 2011. New water heater went in January 2012. I've got a list of projects as long as my arm for "needs to be done", among them refinishing the deck and removing all the carpeting.

Good luck!

(While you're flushing it, replace the anode if at all possible ... keeping in mind that replacing the anode may crack the tank and require a new water heater anyways.)

At 16 years old, I'd look to replacing it.

I doubt you'll be able to get much out of it by flushing, since most of the chunks may be too large to exit through the drain valve.

The problem would not be the thermocouple, if it was you'd be re lighting the pilot.  More likely, the probe of the gas valve/tstat is surrounded by scale, and not sensing the lowering temp fast enough.

16 years is beyond the average life of most water heaters.

Thanks. I guess I'll go ahead and bite the bullet and replace it now.

Flushing it takes five minutes, so why wait?  

The chance this will fix the problem - 0%.



It takes longer to go to the store to get the new unit than it does to change it out - don't wait.  

The chance this will fix the problem - 100%

Replace the dip tube, while you're at it do the anode rod.  Flush it out good.  May help if you remove the tank, take it outside, and swish the water around inside to break up the sediment.