after overfilling the boiler the pressure valve started releasing water out of the overflow. I bled a heater to reduce pressure but it remained high. I now have to leave the cold tap running to stop the pressure valve from pumping out water through the overflow! Why is the pressure not dropping? What should I do?

stressed scot, February 2008

Try disconnecting your filling loop, if still the same turn off the cold inlet valve and see if it remains the same, if it does then the plate heat exchanger may be breached.

Bug A, February 2008