In my previous post I described how I've messed with my current CH HW system to make it fully pumped (S plan). I think I've messed up a perfectly good system but it is totally undo-able. What I need to know is from the following information would the old system have worked successfully so I had HW only when I needed it
hi paul,again first what i think the pipes are. 1. return from ch 2.return to boiler 3.flow from boiler. the system seems like it was put in by someone who did not fully understand the workings of a ch/hw system.It looks like some form of solid fuel appliance was used to heat the water at one time. The cold feed from the header tank should not tee into the expansion in the attic as this can cause circulation in the header tank,oxidation the water and causing a build up of air in the system leading to rusty rads. The by pass at the pump is wrong it dose nothing. The idea of a by pass is to clear the boiler of boiling water after motorised valves close.This is achieved by the pump overrun (normally a stat in the boiler) that runs the pump until boiler cools down so avoiding kettling of the heat exchanger. the by pass should be placed between the flow and return before the valves. Getting back to your question i think the set up would have worked ,but ineficently.My advice to you would be to get rid of the header tank and pressurise the system
