Undemanded heating

[KevvyB]

Hi All.

(Worcester oil fired boiler, vented pumped system with 3-way valve)

I see lots of people are suffering from the problem of radiators warming up when only hot water is selected.

I had this problem and have had the 3-way valve changed, which seems to be the favourite analysis. However the problem remains, and confusingly the radiators (although not all) heat up when just hot water is selected, even though the CH supply pipe from the 3-way valve remains cold (i.e. the valve is working correctly). Is it possible that hot water is somehow getting to the radiators through the return pipes?

 

[seco services]

maybe reverse circulation from the cylinder return going up the radiator return

 

[KevvyB]

Thanks,

Is there some sort of non-return valve available that could be fitted to prevent this? Or is there a simpler solution?

 

[seco services]

you can re-arange the pipework or fit a gravity check valve on the radiator return pipework

 

[KevvyB]

Thanks again!

I will investigate further. Sadly, both options are likely to involve pulling the floor up