Is there a future for vented systems?

[Madrab]

We could go through all the unlikely scenarios all day long.

I think it has long been proven that a vented system is inherently safe, the worst case I've ever heard of is that the system vents over, softens the plastic cistern and then hot water can be released to the inhabitants below.

It has also been proven that an unvented cylinder can explode when it's over pressurised - https://forum.nachi.org/t/exploding-water-heater-in-phoenix/30989/2

There are always risks no matter what system is used but I know which one would be preferred in a failure situation.

 

[sirocosm]

I think it has long been proven that a vented system is inherently safe, ...

In the UK I suppose, as they are mostly the only ones still using unvented systems. In the rest of the world, it has long been proven that unvented cylinders are not an explosion hazard.

 

[Madrab]

Strange why there are so many stories from around the world of unvented cylinders exploding then??

 

[sirocosm]

I think the only hot water cylinder explosion so far in the UK was on a boat, and it was a vented cylinder. Gas explosions occur far more often. Unvented is just not much of a risk.

 

[Ryler]

Is a buffer cylinder on a sealed heating system at risk of exploding?

 

[Madrab]

There are hundreds of stories worldwide of unvented hot water cylinders that have exploded due to over pressurising due to failures or the circumventing of their safety devices and their EV's due to the higher pressure they're held at.

I've never suggested that a well maintained unvented system isn't as safe, I have one of my own that I service regularly, nor would I disagree that there aren't a lot more gas explosions in comparison but it's doesn't detract from the fact that there are loads of stories of explosions from over pressurised unvented cylinders in contrast to unvented.

 

[sirocosm]

Funny how when I lived in Canada, the land of direct-fired gas cylinders, I never heard any "stories" about water heaters exploding. Are you sure they are not just mostly "stories"? If you dig a bit, you will find most stories of cylinder explosions are caused by gas leaks.

 

[bernardgreen]

explosions from over pressurised unvented cylinders in contrast to unvented

unvented cylinders in contrast to vented ?

 

[Madrab]

unvented cylinders in contrast to vented

yes indeed Bernard, thanks for that it was meant to be vented

 

[Madrab]

Funny how when I lived in Canada, the land of direct-fired gas cylinders, I never heard any "stories" about water heaters exploding. Are you sure they are not just mostly "stories"? If you dig a bit, you will find most stories of cylinder explosions are caused by gas leaks.

erm, unless all the stories are just made up by people trying to put unvented cylinders in a bad light then no I don't think so. Even then some of them are electric, not gas fired that had their safety features bypassed or replaced by the homeowners that didn't know any better.

 

[sirocosm]

erm, unless all the stories are just made up by people trying to put unvented cylinders in a bad light then no I don't think so. Even then some of them are electric, not gas fired that had their safety features bypassed or replaced by the homeowners that didn't know any better.

I don't see a hundreds of stories about unvented cylinders exploding.

Statistically, in the UK unvented cylinders are no more likely to explode then vented.

 

[Madrab]

I'm not sure posting lots of thread links in the forum will achieve anything, I found at least a dozen on the first search page of the browser I was using. If you wish to keep flogging it then fair enough.

http://www.theplumbette.com.au/plum...-selling-plumbing-fittings-to-the-unlicensed/
http://www.tamatoledonews.com/page/...nk-explodes-outside-Toledo-home.html?nav=5010
https://www.aplusplumbingprofession...er-heaters/water-heaters-worst-case-scenario/

This isn't just restricted to the UK, anywhere else the statistics are still the same, a lot more unvented systems explode compared to open vented, open vented system are not UK specific.

I've said my bit

 

[sirocosm]

This isn't just restricted to the UK, anywhere else the statistics are still the same, a lot more unvented systems explode compared to open vented, open vented system are not UK specific. I've said my bit

That is just silly, there are no vented systems outside the UK, so I guess no explosions. You cannot say vented are safer outside the UK, because they don't exist. Inside the UK there has never been an explosion of an unvented cylinder, despite millions installed over the last 34 years since 1986 when they (finally) became legal.

So statistically, unvented cylinders are no more likely to explode then vented, in UK or elsewhere.

In any case, trying to pretend vented cylinders are better because they "safer" is not an argument based on facts. Neither are "unsafe" unless you start deliberately tampering with the PRV or vent.

 

[Ryler]

, there are no unvented systems outside the UK

I thought france was full of unvented cylinders?

 

[Ryler]

there are no unvented systems outside the UK, so I guess no explosions. You cannot say vented are safer outside the UK, because they don't exist

If no unvented outside the UK and you also say vented does not exist, then what does exist outside the UK?