High pressure and hot at both rads and DHW

[Simonconfused]

I have a camray 5 oil boiler. The circulation pump had ceased and has now been replaced. However I have some weird problems. The pressure creaps up to 3.2 bar at which point the expansion vessel starts to leak very slightly, tuning the heat setting down keeps the pressure just under 3 bar. The circulation pump constantly runs even when room stat and both heat and water are turned off at the programmer. When the water is set to on I get heat at water and rads. I have to admit that I 'fiddled' with the diverter valve so I am not sure what position this is now in; but even if it is in the wrong position could it have the above effects?
Many thanks
Simon

 

[ChrisR]

Your filling loop is "letting by" - it's supposed to be disconnected.

You may have left your DV latched permanently open? Maybe it's stuck open? It's the DV that turns the boiler on.

Either the boiler's faulty or the pump's been wired in to the wrong place

 

[Simonconfused]

Many thanks for your reply Chris.
The loop is disconnected. I am probably being thick but I don't understand how the DV turns the boiler on. How can I tell what position the DV is in? It turns by hand easily and will rotate by 360 and round as many times as I want!
Thanks
Simon