changing rads on unvented system advice please!!

[philgood]

Hi,

I have moved into a house fitted with oil fired central heating and an unvented Ultrasteel hot water system in the loft.

I want to add some radiators but unsure the correct procedure on draining and refilling on this system.

It has an F&E tank mounted high up so could I just isolate the supply to this and drain down and refill as I would a vented system?

Thanks!
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[codcutter]

It's only the hot water that's unvented. Heating is vented, carry on as normal

 

[Killy Bing]

Cod cutter is correct, only the cylinder itself is at mains pressure, the system will still be vented

as a side note as youre moving into a new home , when you're in the house for the day, turn your boiler hot water off and run the immersion and keep an eye on how hot the water gets and if the presure relief discharges outside.

kingspan had an issue around 2 years ago (i think) with quite a large batch of the immersion stats AND thermal cut outs failing completly!

 

[philgood]

Cod cutter is correct, only the cylinder itself is at mains pressure, the system will still be vented

as a side note as youre moving into a new home , when you're in the house for the day, turn your boiler hot water off and run the immersion and keep an eye on how hot the water gets and if the presure relief discharges outside.

kingspan had an issue around 2 years ago (i think) with quite a large batch of the immersion stats AND thermal cut outs failing completly!

Ok thanks guys..
out of interest, if you look at my photos, why would there be two motorised valves on the inlet to the hot water tanks? Presume the first one closes flow to the tank when water temperature is reached but unsure what the other one does!

 

[BLOD]

the one on the right is the 3 port valve for your heating & hot water the one on the left is the unvented safety valve (shuts if overheat cutout activates)