efficiency of vented as opposed to closed system?

[sparkydave in wales]

Can anyone tell me the difference in efficiency between a closed system and vented, ours is vented at the moment and I'm considering whether it's worth altering it to sealed system (expansion vessel, prv and filling loop with guage)

 

[ScottishGasMan]

Simply sealing the system will not change the efficiency of it.

If you have a configuration problem causing air to build up in system or some other issue then sealing may help it work better, but sealing it wont alter gas consumption or heating output.

 

[sparkydave in wales]

ok thanks, I prefer a sealed system but if there's no difference to the efficiency then I'll leave it as it is

 

[Agile]

The energy efficiency training, which all engineers were supposed to go on about six years, ago taught us that an open vented system is about 2-3 % LESS efficient as a result of heat loss from the header tank and its pipework. This figure comes from the EST.

The cost of converting may be difficult to recover in a reasonable time period.

But sealed systems should in theory require less maintenance.

Furthermore, in the event of a leak, the water loss is restricted to little more than the active volume of the expansion vessel. In contrast a leak from an OV system will be fed by the float valve and can lose hundreds of litres which can cause considerable damage if not quickly discovered.

Tony