Unique hwt situation

What exactly is it that has an upper and lower cylinder and an upper and lower thermostat?

Fortic tank? A hole in either the feed pipe from the header, or the plate that separates the header and hot water tank.

Mixer valves in the system? Faulty mixer valve.

Common enough. Switch the upper one on for a small amount of hot water. Put the other one on to heat a tankful for the bath.

What kind of system is this?

upper and lower elements of what?

How do the water heaters differ from the elements changed above?

We need a bit of background to help. What kind of water heating system. How is it heated (i.e. immersion heaters, gas, solid fuel etc). Some photos might help.

I love your patience John, but it?s a HOH post and your wisdom will almost certainly fall on deaf ears.

I am curious why HOH posts are always so brief as to be almost unintelligible. Are there rules that forbid giving useful info?

Tim

Yup, quite likely...

Don't know, kind of bizarre isn't it?

ELEMENTS!!!

Why are you so terse and failing to give proper details? Come to that why are you using homeownershub when you could get direct contact with sensible people via uk.d-i-y? Has the system ever worked correctly? Are you using an unvented cylinder that has been incorrectly piped up? Is your stop tap fully open? If you have a vented hot water cylinder is there a venturi shower feed in the house?

You have hot water in your toilet? How quaint.

Answer you wired up next doors heater. grin. Brian

I think we need to know if this has ever worked otherwise people are just guessing. Brian

Also weird that they changed all those things without doing any elementary tests first. OK, there's a certain skill to using a neon screwdriver safely but surely *any* idiot can use a volt stick.

Maybe it is one of those fancy Japanese ones.