On Oct 20, 1:44*pm, engwar wrote:
Our water heater has started to leak. It appears to be leaking from
the long copper tube that runs the length of the outside of the
heater. My understanding is that this is an overflow pipe.

We moved into this house 2 years ago and I am not sure how old the
water heater is or when it has last been serviced.

Any suggestions as to what to do here? Is it something a marginally-
handy guy can do himself or should I just call an expert?

Thanks.

that's your T/P valve, also known as Temperature/Pressure. It pops
off whenever the water in the heater gets too hot or the system
pressure gets too high. Check the temp. of your hot water with a
thermometer, and check the pressure at a handy hose fitting (e.g. slop
sink faucet, outside sillcock, etc.) with a pressure gauge on a female
garden hose fitting - available for probably $10 at your local Borg.
If both are within spec as printed on the little metal tag on the T/P
valve (usually 210F and 150 PSI I think?) and they should be - you'd
likely notice scalding hot water or insane pressure - simply replace
the T/P valve. It unscrews from the side of the water heater. You
will need to shut the water off to the house to do this and drain the
hot water tank down to below the level of the T/P valve to do this.
When you shut the water off turn off the water heater so that the
elements don't burn out (electric) or you're heating an empty tank
(either electric or gas.) You'll need to open at least one faucet to
do this to let air into the system.

A new T/P valve of a rating acceptable for a residential hot water
heater should be less than $20 at the Borg, and you shouldn't need
anything besides a pipe wrench and some pipe dope, unless the outlet
pipe is soldered in such a way that it can't be unscrewed, in which
case you'll also need a torch, some flux, and some solder.

After you've installed the new T/P valve, let the "hot" (it won't be,
now) water flow from a faucet until all the air is out before re-
energizing/re-lighting the HWH. Expect sputtering and air from all
your faucets/showers/etc. for a little while until each fixture has
been used at least once.

see here for more than you ever wanted to know about hot water
heaters:

http://waterheaterrescue.com/

I'd recommend, while you're in there, replacing the drain valve of the
HWH as suggested on that web site for ease of maintenance in the
future. You don't need to buy from them, unless you want to - their
drain valve kit is simply a 3/4" dielectric nipple, a 3/4" female pipe
thread ball valve, and a 3/4" male pipe thread to garden hose
adapter. I do recommend leaving a cap on the garden hose fitting as a
ball valve lever is easy to inadvertantly kick. Definitely at a
minimum purchase a brass cap for a garden hose fitting before you
start just in case your drain valve sticks open when you drain the
water heater.

good luck

nate