What’s wrong with my hot water heating.

893bet

Recent background.

Water is heated by solar tubes and oil when needed.

Shower was gone cold-assumed thermostatic mixer was goosed so so got a new bar shower installed as had a column show that I didn’t really like.

No better. Get a flush of heat for a minute and then it goes luke warm.

Looked there now and temp sensor at top of the tank shows 50degrees and bottom at 30. When I run a hot tap (ie one that has no mixer valve) you get a flush of really hot water for 5-10 seconds then it reverts to cold. Turned on oil and got top of tank up to 60 and no difference.

Any ideas?

893bet

Any one?

is the below an additional mixer valve on top of the tank that that tempers hot water?

Can this be adjusted ?

893bet

Any plumbers here at all…… ?

Managed to adjust this fully open and fully closed and makes no difference.

Very strange. So the top pipe into the value I understand is the cold mains which blends with the tank water from below sending what should be hot but not scalding water out from the “centre pipe”. When I turn on a hot tap the the top pipe gets Ice cold as water is pulled through it. I get a flash of hot water before it turns to barely like warm.

Whats interesting is that when I turn off the tap, the top pipe heats up with the within 30 seconds, to very hot; assume there is water moving back from the tank into this pipe. Maybe that’s normal behaviour?

Have plumber booked to change that Valve out and investigate but be a month before he gets to me. Anything else it could be to try and maximise the plumbers visit?

whizbang

Check water supply feed to to the tank is ok, not blocked, turn down or off the cold water mixer supply to see if this makes any difference.

They should probably have the same source so there is no pressure difference. But its probably the mixer.

dathi

sounds like your thermostatic mixing valve as pictured needs replacing