Semi-sealed system

Andrew_Doran

I have an old but reliable Potterton Prima F50 boiler and radiators. My system is semi-sealed, so there's a header tank in the attic, and an expansion vessel, but no overflow pipe. I put a pressure gauge on it and when it's cold, it shows only 0.25 bar (I wasn't expecting more).

So my question.. I'm re-plumbing the system at the moment due to moving things around, and when money allows I hope to have my boiler replaced with a new condensing boiler. Is a semi-sealed setup with low pressure likely to be suitable? Even if it would be suitable, would I be better off running a new mains feed and fill loop and making the whole lot sealed?

Cheers.

Dtp1979

Andrew_Doran wrote: »

I have an old but reliable Potterton Prima F50 boiler and radiators. My system is semi-sealed, so there's a header tank in the attic, and an expansion vessel, but no overflow pipe. I put a pressure gauge on it and when it's cold, it shows only 0.25 bar (I wasn't expecting more).

So my question.. I'm re-plumbing the system at the moment due to moving things around, and when money allows I hope to have my boiler replaced with a new condensing boiler. Is a semi-sealed setup with low pressure likely to be suitable? Even if it would be suitable, would I be better off running a new mains feed and fill loop and making the whole lot sealed?

Cheers.

Yes seal the system. Semi sealed systems were just a product of the boom to stop cowboys getting call backs on jobs

As above, semi sealed systems are a nonsense and should be got rid of where practical .

While you have the system drained think about a magnetic filter on the return pipe to the boiler, the filter is fairly inexpensive, they punch above their weight for boiler protection and longevity.

Andrew_Doran

Sealed it is.

Dtp1979 wrote: »

Yes seal the system. Semi sealed systems were just a product of the boom to stop cowboys getting call backs on jobs

That explains it then. I've had a good few years to think about it, and with what little knowledge I have I couldn't work out why it was done that way.

gary71 wrote: »

While you have the system drained think about a magnetic filter on the return pipe to the boiler, the filter is fairly inexpensive, they punch above their weight for boiler protection and longevity.

I've seen them mentioned before but was put off because the ones I saw online seemed fairly pricey, but now that you mention it I think I'll ask at the merchants, as generally I seem to get far better prices over the counter.

Thanks again for the advice, much appreciated.

Dtp1979

Andrew_Doran wrote: »

Sealed it is.



That explains it then. I've had a good few years to think about it, and with what little knowledge I have I couldn't work out why it was done that way.



I've seen them mentioned before but was put off because the ones I saw online seemed fairly pricey, but now that you mention it I think I'll ask at the merchants, as generally I seem to get far better prices over the counter.

Thanks again for the advice, much appreciated.

You'll pay roughly 120 for a 3/4 filter