I have a 30 Gal kenmore gas water heater from 1981. It is supplying less and less hot water all the time (the water can start out hot, but almost immediately gets warm, then cool... I can barely make it through a shower now).
Although it may be a coincidence, it seemed to start getting bad after I had done a little plumbing (I found a vertical pipe that had been capped off in a wall I was removing. So I opened all the faucets, cut the pipe back, siphoned water out of the remaining stub so that it wouldn't steam when I soldered a new cap on it, and then actually soldered the cap on. I then started up the water and everything seems to be working fine... but now I have this hot water issue).
I have drained the tank and refilled it. Nothing seems to help.
While I'd like to replace it, I'm a little skint at the moment. Is this something that can be repaired? Can a DIY guy do it?