Positioning of Central Heating Vent Pipe

[Karmolekhare]

My central heating system has the vent pipe to the expansion tank positioned in the boiler return pipe. All modern diagrams have it in the flow pipe, just before the cold feed and pump. I understand that this is because of current regulations.

My question is .... what is the reason for the change and would there be any benefit in changing the position of the vent pipe from the boiler return to the boiler flow when I have a new boiler installed?

Thanks for your advice.

 

[nzmanc]

Your pump might be on the boiler return. The vent pipe should be before the pump so there is no over pumping into the header tank

 

[Karmolekhare]

Many thanks!

 

[glasganny]

Gents (and Ladies) please let me know if I can have the vent and fill pipes on the return to the boiler. My boiler is situated outside the house and has two pipes going up to the attic and accrross the house. From the attic they then connect to two manifolds (one for feed and one for return) and these then connect to the rads. It is a pressurised system and I am installing a 30KW solid fuel back boiler. The boiler manufacturer insists on a vented system so I have to change from pressurised to vented.

I understand that the vent pipe must come just before the pump, however, while I could relocate the pump to the attic, it would be about 10 yards away from the boiler and it would not be possible to connect it to a pipe thermostat to trigger the pump when the boiler temp was say 50oC.

This is why I was thinking of the F&E pipes on the return pipe.

Any suggestions would be very welcome.


Thanks