Hot water cylinder question

[donners90]

Evening all,
I've had a look through previous posts, bit can't seem to find what I'm after.

We have a "conventional" CH system run from a oil fired boiler (about 4 years old). The CH works fine, and the water comes out of the taps hot. VERY hot. Thinking that the stat was broken I changed the hot water cylinder tank stat and set the temp to 45'C. However the water is still coming out very hot. When I touched the copper of the tank behind the stat it was luke warm, when the water coming out of the taps is scalding! Setting the stat to ~20'C seems to trigger the stat to switch off the HW pump, but the hot water is still scalding!

just wondering what might be going on inside the tank... Limescale build up? Does it need changing or is there something I can do to fix it?

If anyone can shed any light on the issue I'd welcome your opinions and advice.

many thanks

James

 

[Agile]

Sounds like an installation problem.

Can you post a picture of the cylinder showing all the pipe connections?

Tony

 

[Dan Robinson]

Top of the tank will be much hotter than the bottom.

Hot water rises, cold water sinks.

The water stratifies, and you end up with layers of hot water developing from the top down.

The cylinder thermostat only switches at the very last moment.

Try removing some foam a couple of inches above the thermostat and see how hot it is.

 

[ianmcd]

Do you have an electrical immersion heater ? are you sure its not switched on ?