Big Neil

Solar Store - heat battery

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althlugh I know the difference is in the name, practically speaking, what is the difference between a vented and an unvented cylinder. I've got the V right haven't i, VENT?

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22 minutes ago, Big Neil said:

althlugh I know the difference is in the name, practically speaking, what is the difference between a vented and an unvented cylinder. I've got the V right haven't i, VENT?

 

An unvented system is under pressure so needs commissioning by somebody with a bit of paper to their name and thereafter an annual check.

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gotcha . So why would one be under pressure and the other not be? are they for different applications? Also, where do the vented ones, vent to?

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21 minutes ago, Big Neil said:

gotcha . So why would one be under pressure and the other not be? are they for different applications? Also, where do the vented ones, vent to?

 

Erm...the clever people will be along shortly, me, monkey see / monkey do. 

 

Top of my head unvented can go anywhere as at mains pressure. You don't need a cold water tank to feed it. Better pressure than traditional vented systems for things like showers. Crap can't fall into the tank as there isn't one...

 

They can blow up though! :)

 

Vented vent to the atmosphere / back to the tank via expansion pipes.

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Both strictly are "under pressure"

 

An unvented cylinder is usually pressurised to 3 bar, regulated by a pressure reducing valve.  Expansion is taken care of with an expansion vessel with safety relief valves in case that fails.

 

A vented cylinder is pressurised by the water from a header tank usually in the loft. Because the tank is usually not very high, the pressure will usually be less than 1 bar.  Expansion is taken care of by venting back into the header tank.

 

Vented is considered old fashioned, you get poor water flow rates due to the low pressure, and often have to fit a pump if you want half decent pressure and flow from a shower.

 

Unvented, because it runs at a higher pressure delivers much better flow and pressure for a decent shower, there is no header tank in the loft to freeze in winter and less chance of the water getting contaminated by muck in a header tank.

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That's the crack Mr @ProDave - exactly what i was after - So basically, get an un-vented cylinder unless you've a penchant for buzz bombs, gout and like drinking condensed milk straight from a can.

 

I know i'm sort of digressing from the original topic somewhat but it sort of still relates to my understanding of heating as a whole.

 

IF you feel so obliged, So far as you are able, would you mind grabbing some product links from the interweb of a pre-plumbed un-vented cylinder, expansion vessel and aside from pipes any other specific bits of kits one might need, if putting together a setup which was to also include an element to take excess PV generation.

 

Just so I've a basis for comparison. Otherwise I 'll likely end up looking at any old crap and miss stuff out as well.  Or should I start another thread do you think? I'm proper crap at all this forum stuff, always waffling around me....

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