[Shop-talk] Hot Water Heater 'Heat Trap'

[Randall]

>    When I was switching the lines I did not notice anything 
> in the pipes but
> then I really wasn't looking for anything.

"Heat traps" can be check valves, but normally they are just pipe.  The idea
is just that you form a U-bend (kind of like a sewer trap), to help
interrupt circulation within the pipes due to convection. Eg,
http://tinyurl.com/36xh656

My guess would be that the builder left out the dielectric unions at the
heater connections.  I would pull apart the heat trap on the outlet side,
and check for pipes clogged with galvanic corrosion.  If that's what you
find, replace the pipe along with a dielectric union.

You should also check whether the builder used the water pipes for safety
ground.  If so, my suggestion would be to wire the grounds directly to a
ground rod and not use water pipe.  If that isn't feasible, at least make
sure they aren't tied into the hot water pipes.

-- Randall