Expansion Vessels Positions

[John Carroll]

 

I thought I had this figured out but can't do it now, someone else might.

 

Its generally recommended that a EV is installed on the pump inlet, the system pressure then runs at a higer level than if it is installed on the pump discharge, if a second EV is required for system expansion etc then it might be teed into the existing EV but certainly on the same side of the pump if not. Query is, what happens if one EV is teed in before the pump and one after it Expansion Vessels Positions Rev0.xlsxExpansion Vessels Positions Rev0.xlsxExpansion Vessels Positions Rev0.xlsx since the point of no pressure change is where the EVs are teed in.

 

 

Expansion (2) Vessels Positions Rev0.xlsx

[JohnMo]

3 hours ago, John Carroll said:

Query is, what happens if one EV is teed in before the pump and one after it 

Would you then correct he plumbing? one EV is in the wrong place I.e. both should be upstream of pump.

[John Carroll]

Of course, easy to install it correctly on a heat only boiler, or a system/combi boiler where one would expect the internal EV to be teed in allso (and allways?) to the pump inlet but I seem to recall someone who installed a external EV on a combi and had some problems but found subsequently that the internal EV was installed on the pump outlet by design if i'm remembering this properly.