the plumbing is for heater tank, not instant heater - note the metal/chrome piping
you need to know the max pressure at the place, these instant heaters can hold up to certain pressure only

the control valve should be at inlet, not outlet
you just need 1 valve to control the water flow

for those instant heater with built-in pump, stop the heater before closing the valve

the square shaped thing is for water flow sensor, to activate the heater only when water flows... this thing also can fail, and cause heater to either not function, or continuously boil the water



I suggest you find a different plumber technician

This post has been edited by alexei: May 29 2024, 10:19 AM

I think average users don't want to know these.... reality is a bit sad
see the photo, oredi warning there... chrome pipe or faucet should not be used
electric, water, metal should not mix, and the recipe is complete here
just lucky the ELCB is tripped, else later found out "elcb is bypassed because always trip since the plumbing technician say is ok"

wait... the heater is connected to the hot water supply of the whole unit?