boiler pressure keeps dropping

[upperplumbers]

it could be a few things:
1. if it takes more than 1 day pressure to drop than a leak sealer will stop a small leak in the system. Just inject it into the central heating system like it says in the instruction
2. to see more

[DOUGALMCD]

I would always prefer to fix system leak properly instead of patching it up as above mentioned.

[trent1579]

check to see if there are any leaks if there are no leaks it is the expansion vessell which is either knackered or needs pumping up,if you can locate the expansion vessell it has a schrader valve(same as car tyre) simple let some air out if water comes out,the expansion vessell needs replacing,if no water comes out then the expansion vessell will need repressurizing normal to 0.5bar to do this the system needs to be depressurized then use car pump to pump up to 0.5bar

see link for more help
[ame=http://www.youtube.com/watch?v=kaKbGFxcyXs]How to check the pressure of the expansion vessel. - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=KeO2gswQQe4]How to recharge an expansion vessel in a combi boiler - YouTube[/ame]

[ricescooper]

I've got the same boiler and had this issue for a while now. Its really weird because the pressure in the system can be fine for months then it will play up again for no reason.

I had a major problem that the insurance had to fix but they took out everything and didn't put it all back with the same care as originally was taken to install kitchen, boiler, etc. I've had one problem after another since they done the work, all seemed fine at first then everything started falling apart after about nine to twelve months.