Pressure vessel in loft - does it need insulating?

With a pressurised central heating system, all pipes and taks are insulated in the loft apart from a small pressure vessel which is located on the loft floor above the insulation.

It was suggested this should be insulated as it consists of half water / half air.

I haven't had a problem that I know of so far. Does this tank need insulating?

Thanks for any info

My instincts tell me that yes it should be because if you don't it will be the weakest link in the system.

Is there some other reason your concerned that maybe it should not be insulated. I'm no expert btw

Yes it will require insulating, however, it also needs access for testing. I would buy some rigid insulation board (polyiso) and build a small removable box out of the insulation and place over the vessel. Remove any insulation from below the box to the ceiling to let heat rise from the room below into the box.

If the vessel freezes you will have no expansion in your heating system when it is on and it could have serious consequences if the 3 bar safety valve were to fail.

All the sealed systems that I have seen, have the expansion tank in the Hotpress. It is not required to be above for a head pressure, as the system is already pressurised