alpha 240 P over pressure on ch and poor dhw temperature

[jimfay]

Pressure increases beyond 4 barr when turned on beyond the lowest setting more or less instantly.

Has needed water pressure top ups reguarly but oddly not recently.

Hot water performance is also reducing.

No problems with regard to radiator bleeding.

Different symptoms to the fixed diaphragm 4 years ago.

Would really appreciate any ideas - its freezing

Cheers.

 

[gas4you]

Expansion vessel has lost its charge or is knackered and is full of water.

Search on here for re-pressurising an expansion vessel.

 

[twgas]

sounds like the pressure vessel needs recharging, also the prv will need changing as it appears to be sticking (should open at 3bar)-and its a safety device

 

[Gasguru]

And your filling loop is not closing off - hence no need for the regular top-ups. Hot water performance may be suffering due to partially siezed diverter or partially blocked plate heat exchanger - probably caused by those regular top-ups.

 

[bengasman]

Hot water performance may be suffering due to partially siezed diverter or partially blocked plate heat exchanger - probably caused by those regular top-ups.

which means your system now needs a fush and your h/e taken out and cleaned, or a powerflush which does the job better and will clean the h/e too, so you don't need to take it out.

 

[jimfay]

That REALLY helped, really. Fixing tomorrow. Bring on the re-pressure!

You're all most excellent and good things should come to you.