Vented Combi

[Mike2007]

Went to a house today and the boiler confused me. It was a Combi oil boiler of sorts Worcester 20-25kw Heatslave that was VENTED.
It has No expansion vessel and it seemed to have unvented hotwater from the internal heat store, that was connected to the mains cold water!?
I just don't get it, if it is in effect "sealed" it should have a blow-off and a method of expansion?? Its very old, maybe 15+ years

 

[twgas]

I dont do oil but have seen open vented gas combis, MIs will say if its ok. If there is no exp vessel one would have to imagine its designed for open system.

 

[Dan Robinson]

The OP is confusing primary water and domestic water.

Bit worrying is he's working on boilers for a living.

 

[twgas]

The OP is confusing primary water and domestic water.

Bit worrying is he's working on boilers for a living.

Thats ok its oil, not gas

 

[Mike2007]

The OP is confusing primary water and domestic water.

Bit worrying is he's working on boilers for a living.

Nope. It has Flow, Return, Mains cold, DHW, F&E pipe

It was something I had not seen before and could not work out?

 

[Dan Robinson]

and could not work out?

Hence the worry.

If it has a header tank, then it ain't sealed innit

it should have a blow-off and a method of expansion

Like the header tank and vent pipe?

If in doub, read the destructions.