wrote in message
oups.com...
I didn't think it was confusing, but okay...

4. 40 gal., 40,000 BTU gas water heater. 5 years old? Just a
guess...bought the house 1.5 years ago. Manuf. date is 1996. Can't
see the inside, but the outside looks mint.

You say the "Manuf. date is 1996" and it's 5 years old?


Have you checked the hot and cold water pipes leading into the tank? As you
face the thermostat, the hot is on the left if the connections are on the
top of the unit. ("hot" may even be stamped into the top of the heater near
that port) After running the shower for a while, is that pipe hot? It
should be. If not, the hot & cold connections could be backwards...

...or they're hooked up correctly, and the thermostat is bad. They're
cheaper than a new water heater and easier to install, so I'd try that
first.