boiler pressure

[ainger]

I have POTTERTON PERFORMA 24 COMBINATION BOILER WHICH WAS FITTED 3 YEARS AGO. RECENTLY IVE NOTICED THE WATER PRESSURE NEEDLE START TO RISE. NORMALLY THE BOILER RUNS AT ABOUT 1.5 BAR BUT NOW CREEPS UP TO 2.5 AND BEYOND. I HAVE BEEN DRAINING SOME WATER OUT OF THE SYSTEM IN ORDER TO LOWER THE PRESSURE. THIS WORKS FOR A WHILE BUT THE PRESSURE GRADUALLY BUILDS UP AGAIN. I ALSO NOTICED WATER DRIPPING FROM THE NUT ON THE FRONT OF THE HOUSING OF THE CENTRAL HEATING DIFFERENTIAL VALVE. I CHANGED NUT AND DIAPHRAM HOPING THIS WOULD SOLVE THE PROBLEM. THE WATER HAS STOPPED DRIPPING BUT THE INDICATOR IS STILL SHOWING HIGH PRESSURE. THE BOILER SEEMS TO WORK FINE NO FUNNY NOISES PLENTY OF HOT WATER AND HEATING IS OK.
COULD YOU PLEASE HELP ME TO IDENTIFY THE PROBLEM. I CANNOT AFFORD A PLUMBER AT THE MOMENT. I HAVE A GOOD BOILER PARTS STORE LOCALLY AND HOPEFULLY WOULD BE ABLE TO FIX IT MYSELF. THANKYOU.

 

[chrishutt]

AAAGH - please don't SHOUT. Just press the Caps Lock key and I'll try to answer.

Meanwhile, look at filling loop info in the sticky reference topic.

 

[gazthepottertonengineer]

god ive got a headache now
possible problems are

1. filling loop is letting bye check this by disconecting chrome hose one end and if water still comes out you know its letting bye and needs replacing

2.expansion vessel needs represurising or replacing

3.hot water plate heat exchanger has a pinhole in it and is letting the cold water mains into the central heating side which i have had a couple of times with this boiler

 

[ainger]

thanks for your advice regarding this subject tried testing the filling loop no problem their could anyone advise me on the best way to repressurize the expansion tank