WS wrote "I would advise anyone with one of these cylinders to install a quality make additional pressure relief valve set one bar above the pressure reducer valve on the hot draw-off pipe near the cylinder. Please DO NOT do this. It is against regulations. If fitted it would need a separate discharge pipe. It is not against any regs at all. They only thing you got right was that a separate discharge pipe is needed. And they allow these people into people's homes. Science. Facts. Sense. Of which all evaded you.
Not a single sign of water anywhere in the cupboard, and the tank hasn't moved for years. Looks like taken in and out - moved.
One of the most important points on an unvented cylinder is the discharge pipe sizing & installed correctly.Also the fact manufactures allow the discharge pipework to be done in plastic & connected to soil pipes is wrong (my opinion). They can be connected to a stack using a HepVO trap. I These apartment buidings should be designed with large steel common pipe risers in an internal vertical duct to collect the discharge safely. They should have DHW only heat banks which do not require a discharge pipe or overflow.
Q. What would happen to a heat bank/thermal store if the safety devices were incorrectly fitted or blocked?? (i.e. if the feed and expansion were blocked). Fitted correctly, they are no problem and service free. A correctly fitted unvented cylinder not serviced can kaboooooooom. See the difference. Of course you don't There is also the discharge pipeless DHW only heat banks which are fail-safe.
water systems, for your information the only system that has claimed a life in the UK was a VENTED SYSTEM the one where the young child was killed from boiling water, That was incorrectly fitted. Unvented cylinders have exploded. They have. Read this thread. One lifted the roof of a house. Oh and don't forget thermal stores can be unvented as well, The fail-safe versions are vented.
The main problem with WS argument is that EXACTLY the same safety devices are used on gas boilers. But worse, any (e.g.) HEx "explosion" could result in a ruptured gas pipe. You are saying two wrongs make a right The effects of an unvented cylinder exploding is catastrophic - death situation. There are zero-risk alternatives. Get it? Of course you do not. So let's ban them, hot water (since lots of elderly and babies die from it), and anything else that has caused injury or damage. TMVs
WS,I am aware manufactures state plastic pipe & Hep french letter traps can be used my point is I would never use that method.The paronoid explosion thing you constantly talk about is theory to you because you you have never installed one,as i have said many times lots of appliances will explode if installed incorrectly.
No point in discussing anything with the lying plonker, What part of the two exploding cylinders (one lifted a roof) didn't you understand? They did explode despite your tiny mind thinking they never.
Oh so now you're proposing to heat a thermal store by electicity, even if the cost is 3-4 times more expensive than gas and a whole lot less eco-friendly. Or would you still install a gas boiler that uses the same safety devices as an unvented system?? I'm guessing your thermal stores use completely different stats to those found on unvented cylinders - your ones never fail. TMVs never fail either. An expanison pipe on a vented system has never become blocked. Ever. Basically anything you quote never fails and everything else does. Sad man. The most tragic thing is: I think that you do actually belive the constant prattle you speak. BTW what happens when your stats fail and the house is filled with skin-burning steam??
The paronoid explosion thing you constantly talk about is theory to you Read back on the thread. Two unvented cylinders exploded - one lifted the roof. What didn't you understand about these explosions? As regards to flats DHW only heat banks are available with no discharge or overflow pipes. Get to know what is on the market and use the most advanced and fail-safe products. Do not be an aficionado of Ned Ludd.
Oh so now you're proposing to heat a thermal store by electicity, I did? lease re-read. I'm guessing your thermal stores use completely different stats to those found on unvented cylinders - your ones never fail. You must understand the differnce between "fail" and "failsafe". You don't know the difference. TMVs never fail either. They don't explode and take down the side of a house. expanison pipe on a vented system has never become blocked. It have two pipes out of the cylinder - cold feed being the other. You are limited to changing bathrooms and hold no engineering analytical skills.
Romeo60: One of the most important points on an unvented cylinder is the discharge pipe sizing & installed correctly. Look at: http://heatweb.com/products/cylinders/heatbank/heatbank.htm Click on the Pandora link. http://www.heatweb.com/specs/Specification%205670-1.htm No discharge or overflow pipes, no cold water tanks, full DHW mains pressure and unpressurised. Ideal for flats. Get to know what is on the market.
These are good too http://www.heatweb.com/products/cylinders/amazon/amazo nmk2.htm They are not, as they can explode. They obviously sell those to the hard of thinking.
mr water systems the roof lifting experience you mention all the information you have cut and pasted are all from a mr mark jones a fire spokesman for hampshire , none of the information can be classified as fact and at this date should only be treated as hearsay . further more they only guess the roof had taken off and landed back on the spot at which it would normaly be , because and i quote " all the tiles where loose " all the damage caused will have to be verified by a structural engineer before it becomes fact ! now to the suposed fault ! the blame is being put down to a faulty electric hot water tank which had the water turned off and the immersion left on "it just got hotter and hotter ", there is no mention in the info that i have seen about it being unvented or otherwise conclusion - electrical fault ? did the immersion have a stat ? did it work ? there has also been a death and this is fact from a decomissioned back boiler that exploded source daily mail 29th oct 2008 again this comes down to heat being applied to water original thread was posted on greenbuildingforum.co.uk under the name nadnerd70 and was posted 4th feb 2009 where you will also find our old friend water systems
mr water systems the roof lifting experience you mention all the information you have cut and pasted are all from a mr mark jones a fire spokesman for hampshire , none of the information can be classified as fact and at this date should only be treated as hearsay . I think the fire people knew about it as they attended. They never made it up. now to the suposed fault ! the blame is being put down to a faulty electric hot water tank which had the water turned off and the immersion left on "it just got hotter and hotter ", there is no mention in the info that i have seen about it being unvented or otherwise There is a picture of a steel mangled cylinder outside of the house - that is unvented. The reason it exploded was that the safety devices failed. It would not happen using an unpressurised heat bank - DHW only or integrated CH & DHW. conclusion - electrical fault ? did the immersion have a stat ? did it work ? there has also been a death and this is fact from a decomissioned back boiler that exploded source daily mail 29th oct 2008 again this comes down to heat being applied to water Fantastic observation - "heat being applied to water". Fantastic!
W.S Whilst you appear to answer all and sundry, perhaps you could respond to my comments on the original posting. Wilko47 did not report an explosion in the OP, contrary to your statement and YOU were the first person to describe what had happened as a "violent explosion". Until you recognise the errors in your statements, no-one will take your suggestions seriously. If you cannot give ground on statements of fact, then, you must accept that that any credibility you have is compromised.
Wilko47 did not report an explosion in the OP, contrary to your statement and YOU were the first person to describe what had happened as a "violent explosion". He wrote "explosion" and "violent". That better?