Help me understand my heating system please.

[DoNotUseFullName]

My heat source is an oil boiler and it is a wet heating system. I thought it was an open vented system as there is a feed and expansion tank in the attic. However, on closer inspection, the F+E tank is not actually connected to anything. So it looks like it was at some point it was changed to a sealed system? There is a small expansion vessel in the attic also.

Does this sound likely? (I ask as everything in this house is quite old/basic, and I find it hard to believe money was spent on such change! I assume it wouldn't be cheap).

In addition, the hot water cylinder is vented, so it that normal to have a sealed CH system and vented hot water cylinder? And does this mean that the water is directly heated by the boiler, rather than via a heat exchanger in the cylinder?

Thanks in advance!

 

[DoNotUseFullName]

Hmm, just checking the boiler manual, and it says it's not designed for a direct cylinder. So I would assume in that case it needs an F+E tank?

 

[terryplumb]

Sealed / pressurised heating system with vented hot water cylinder is common. The cylinder ,if it is heated by the boiler, would have a coil inside.