potterton bolier pressure when heating on

[eddiereader]

Have a Potterton HE 24 Plus condensing boiler (about 2 years old) that works fine normally. However, put the heat on the other night and noticed that the pressure rose to 3 bars, which the manual identifies as an error state. When the heating was last in regular use, before the 'barbecue' summer, there were no problems.
All the radiators were as warm as expected although the main one in the hall did take a little while for the bottom part of the radiator to be as warm as the top part. I suspected a blockage there but elsewhere found that this may be caused by flow imbalances. Opening up the valves seemed to improve matters a lot.
No problems with pressure when heating just the hot water.
Anyone have any ideas? A blockage in the radiator path sounded the likeliest to me but the radiators are nice and warm. Should I flush it anyway, last flushed about 18 months ago and the results looked good?
Have seen one posts on this forum where someone with precisely this problem but a different bolier was recommended to change the boiler. On a boiler of this age is this a possibility, i.e. a boiler fault?
Thanks
Eddie Reader

 

[corgiman]

have a search on here for expansion vessels

 

[eddiereader]

corgiman
Thanks for the reply. Did some research on expansion vessels and that certainly fits the bill.
I see quite a few references to re-pressuring this vessel for a Potterton 80. Do you know if the same is true of a HE 24 plus? Although I can see nothing in the manuals as to how this might be done.
Finally, this boiler is only 2 or 3 years old, is it to be expected that ( assuming it is the expansion vessel) such a part should fail so quickly?
Thanks
Eddie Reader

 

[powell30]

If you look on top of the boiler at the back you will see a red pressurised vessel (expansion tank) with a shraeder valve on.....use a foot pump to pump up your EV to 1 bar.......remember to drain the system first before you pump up the EV. If this fails you will need it replacing

Secondly, if your system is dirty (sludge) it may well have contributed to a faulty ev. You have pointed out you have cold spots on your rads...a common indicator of a dirty system