BG Grundfos multihead flow rate

[Nige F]

probably redo some of the pipework in/around the expansion tank.

That ballvalve and overflow arrangement are so wrong ! The valve should be above the overflow. New tank needed.

 

[Ben565]

I think there's probably a lot wrong with that arrangement, the tank doesn't even have a lid it's just got lagging over it. Agreed it needs re-doing with a new tank. It's finding somebody reliable to come and do it for me.

 

[DP]

I did have someone come take a look at my system and check out the potential causes of hot water in my expansion tank. They told me it's because I'm running the boiler constantly, all the TRV's are closing, and I have the pump speed set too low (speed I). For reasons they didn't want to go into, that's apparently causing hot water to end up in the expansion tank. And I should leave the pump set on speed II.

Check the Expansion cistern while some one switches the heating or hot water on. There may be a delay of some 20 seconds once the demand is activated.
Check for heating alone and then hot water alone.

That plumbing is incorrect. You will find the vent will be dripping with increase in pump speed and at surge of pump starting
The section between the ven and feed might be sludged up too ( use a magnetite and see if it sticks to copper pipe)