Worcester 24 Combi High Pressure Problem

[pg325]

When cold the pressure is usually at 0.75 bar but when the heating is on the pressure rises quite quickly to 3+, I then have an issue of needing to top up the following morning as the pressure drops to less than 0.5 bar.

I can't see ant leaks.

Could it be dumping water through the overflow as the pressure is to high?

What causes high pressure (assuming 3+ is too high)

Thanks.

 

[Bamba71]

its could be the expansion vessel needs re-pressurising, hot water expands when heated & the expansion vessel takes up the pressure, if the expansion vessel does not take up the pressure the pressure within the boiler & pipework rises & when the pressure reaches about 3.5 bar the pressure relief valve will open & release the water to outside then the water pressure will need topping up like you say, check the manufacture instructions on how to re-pressurise the expansion vessel first as it wont cost you anything before you start paying out for any parts.