Another question for a plumber.

[mudnut]

G'day all.

The mud family has only
recently bought and installed
a new 310 litre single
element electric water heater.
Most of the time, when we
open a hot water tap we
hear a loud metallic pop
coming from the unit.
There is a temp regulator
fitted for the bathroom.
The old one never did it.
I am wondering if it is the
release of pressure because
the new relief valve is working
properly. Is there something
I can check?

[threedogs]

Have you bled the system from all air?
does it sound like water hammer?

[mudnut]

It doesn't sound like hammer,
but I will bleed the system again.

[mudnut]

It is still making the noise
after I bled it.

[my third 256]

do you washin hot water if so try turning it off at the taps and see if this helps
because of sudden drop in pressure can make washers bounce
also is there a one way valve fitted to the hot water unit on the cold pipe going in
this also stoppes the backlash from pressure

[my third 256]

do you washin hot water if so try turning it off at the taps and see if this helps
because of sudden drop in pressure can make washers bounce
also is there a one way valve or non return valve fitted to the hot water unit on the cold pipe going in
this also stoppes the backlash from pressure
http://www.truwater.com.au/plumbing-parts-accessories/ball-valves-stop-cocks/duo-valve-non-return-isolation-valve-15mm-1-2-ni50-c-m-x-m?gclid=COTk4oj7ycYCFRaXvQodYBAMng&zenid=b6ab56861fe23704658ffc5e9812f301

[mudnut]

Thank you for the reply. I will
check all of that when I get home.

[mudnut]

There is a one way
valve and it is
installed the correct
way. I pulled
the relief valve
and the noise
seems to be coming
from inside the tank.

[my third 256]

is pressure valve the right one eg pressure rated or it could be faulty
get plumber out who installed it will be under warranty from manufacturer or ring them to see what to do

[mudnut]

It would be easy for me
to swap it with the old one
to see if that is the problem.