were to put exspansion tank

[paulgid]

hi all
my central heating system is a open vented and always needs venting so i am going to make it in to a sealed system but unsure were to put exspansion tank.on the flow or return?and safety release valve on flow or return.

regards paul

 

[Renewable M]

The exp vessel can have a longer life if it is put on the return, as the return is cooler and helps protect the integrity of the bladder inside the vessel.

Conversely, excessive expansion caused by temperature will often emanate at the heat source (boiler for example) so the discharge valve should be near the heat source on the flow.

Over pressure can be caused by a filling loop not fully closed also.... but you are unlikely to have the monumental pressure required to compromise system integrity to failure before 1) the exp vessel has exceeded its compensation and 2) the blow off is spewing into the garden.

That said, both of these are slightly trainspotter answers.