Hot Water Bypass heating other radiators

[Quiggles]

The last few days have been pretty warm so I delayed putting the heating on for a while in the evening, but the hot water circuit was left on. (I have a heatbank from DPS if that makes any difference).

However I noticed that the hot water bypass circuit which just heats the towel rails must have on the return, pushed back through the upstairs radiators and heated them a little as well. The central heating and bypass circuit share the same return piping, so can easily see how this could happen.

Would a check valve on the central heating flow stop this from happening?

[BruceB]

I have a DPS heat bank in the cellar with 3 other stories above it in the house. I found the gravity circulation was powerful enough to cool the heatbank overnight when everything was off. I ended up adding a zone valve to the CH to stop it. You may have a similar problem (gravity circulation through the CH pump) and if the pressure is not much then a check valve could do it, but was not good enough for mine.

The HW return and CH returns should NOT normally be shared in your setup as one is potable water and one is inhibited mix, but I may have misunderstood your description.

Regards Bruce

[Quiggles]

Thanks for that.

No its not potable water on the "hot water" circuit - thats just the bypass circuit that runs when hot water is being heated - potable water never comes in contact with heating water; as on the heatbank incoming mains cold water is only heating through a plate heat exchanger.

I guess I should try a check valve as a starting point.