Hot water cylinder upgrade

corkgsxr

gary71 wrote: »

it's dangerious to never say never, it has happened and can happen and every cylinder installation should be approached as it could happen, paranoia is a beautiful thing.

It's always the welds, I'm told by cleverer people than myself that's it's to do with electrolysis.

You could equally say a gas boiler is unsafe, if you have a PCB glitch or stats fail it could be unregulated sealed system capable of boiling to steam.

corkgsxr

corkgsxr wrote: »

To get 178 degrees in the cylinder you need to get 178 degrees in the coil. You can't get more heat than you put in

It's not possible in a open vented stove to get 178 degrees water temperature.

And besides if the temperature goes over about 90 degrees the pressure/temperature relief will vent hot water,

If you get a opportunity go on a G3 course in the North, it's a safety course you must go on just to fit or work on unvented in the UK, every cylinder is inspected by the local building inspector on installation, this is because of the real danger unvented poses when fitted by installer that don't get it.

shane0007

You have missed the whole point.
Forget 178C. The solid fuel gets to 100C. The cylinder is now at 100C, ok? No problem there as at 3 bar pressure the cylinder will not convert to steam as its boiling point is 178C at that pressure. With every bar of pressure you get a direct increase in temperature free of charge. You must have missed the Boyle's Law lesson in school!
Now you have a higher temperature within the cylinder as it is under pressure. Still no problem as the boiling point is still at 178C.
Tap opens. Now the pressure within the cylinder is brought back to atmospheric pressure, i.e. 0 bar pressure. Boiling point is now back to 100C and therefore the 300 litres of water will convert to steam as it is now suddenly at the reduced boiling point of 100C. The enormous volume of steam has to convert to somewhere.

http://m.youtube.com/#/watch?v=ekEHfihiNz4&desktop_uri=%2Fwatch%3Fv%3DekEHfihiNz4

shane0007

gary71 wrote: »

If you get a opportunity go on a G3 course in the North, it's a safety course you must go on just to fit or work on unvented in the UK, every cylinder is inspected by the local building inspector on installation, this is because of the real danger unvented poses when fitted by installer that don't get it.

It is also run in Metac, Mountrath, Co. Laois.

corkgsxr

gary71 wrote: »

If you get a opportunity go on a G3 course in the North, it's a safety course you must go on just to fit or work on unvented in the UK, every cylinder is inspected by the local building inspector on installation, this is because of the real danger unvented poses when fitted by installer that don't get it.

Can you tell me how you get more than, 100 degrees in the cylinder.

Even if the stove boils that's 100 degrees. At atmospheric pressure it can't exceed 100 anything after that is a increase in latent heat not temperature.

Even that's ignoring the tempature relief to keep it below 90 degrees

corkgsxr

corkgsxr wrote: »

You could equally say a gas boiler is unsafe, if you have a PCB glitch or stats fail it could be unregulated sealed system capable of boiling to steam.

You could, but I won't, let's instead talk about the 3 bar blow off and the overheats and low water content heat exchangers now that would be sensible chit chat, have you seen superheated steam leave a unvented cylinder:eek: puts manors on you, did me, gas boilers and unvented are not for the same conversation.

corkgsxr

corkgsxr wrote: »

Can you tell me how you get more than, 100 degrees in the cylinder.

Even if the stove boils that's 100 degrees. At atmospheric pressure it can't exceed 100 anything after that is a increase in latent heat not temperature.

Even that's ignoring the tempature relief to keep it below 90 degrees

I honestly don't know where to start, go on a course, unvented is serious and it shouldn't be left for a Internet site to give you the information you need to work safely.

corkgsxr

shane0007 wrote: »

You have missed the whole point.
Forget 178C. The solid fuel gets to 100C. The cylinder is now at 100C, ok? No problem there as at 3 bar pressure the cylinder will not convert to steam as its boiling point is 178C at that pressure. With every bar of pressure you get a direct increase in temperature free of charge. You must have missed the Boyle's Law lesson in school!
Now you have a higher temperature within the cylinder as it is under pressure. Still no problem as the boiling point is still at 178C.
Tap opens. Now the pressure within the cylinder is brought back to atmospheric pressure, i.e. 0 bar pressure. Boiling point is now back to 100C and therefore the 300 litres of water will convert to steam as it is now suddenly at the reduced boiling point of 100C. The enormous volume of steam has to convert to somewhere.

http://m.youtube.com/#/watch?v=ekEHfihiNz4&desktop_uri=%2Fwatch%3Fv%3DekEHfihiNz4

They kept heating the tank with flame, huge heat. a coil at 100 degrees won't do that

You can't get free heat, energy can't be created or destroyed only transfered. Compress water at 100 degrees and you can compress it all you want but it's still water at 100 degrees. It doesn't rise in temperature.

gary71 wrote: »

You could, but I won't, let's instead talk about the 3 bar blow off and the overheats and low water content heat exchangers now that would be sensible chit chat, have you seen superheated steam leave a unvented cylinder:eek: puts manors on you, did me, gas boilers and unvented are not for the same conversation.

Mm and what about a pressure/temperature relief valve. It can't rise over the set pressure or temperature.

shane0007

corkgsxr wrote: »

Can you tell me how you get more than, 100 degrees in the cylinder.

You are still not reading my post!

shane0007 wrote: »

With every bar of pressure you get a direct increase in temperature free of charge. You must have missed the Boyle's Law lesson in school!

I should get paid for this! Look it up, Boyle's Law, that is.....

corkgsxr

gary71 wrote: »

I honestly don't know where to start, go on a course, unvented is serious and it shouldn't be left for a Internet site to give you the information you need to work safely.

So can you explain how you can get over 100 degree when your heat source can't go over 100 degrees.

You can't it defys physics.

If it can't get over 100 degrees it won't turn to steam out the taps.

And all this is still ignoring a pressure/temperature relief that will keep temperature below 90 degrees.

shane0007

corkgsxr wrote: »

You can't get free heat, energy can't be created or destroyed only transfered. Compress water at 100 degrees and you can compress it all you want but it's still water at 100 degrees. It doesn't rise in temperature.

You can.

corkgsxr wrote: »

Mm and what about a pressure/temperature relief valve. It can't rise over the set pressure or temperature.

They can fail, they can stick and oh yeah, Fruitloops can blank them, which is more often the case!

shane0007

corkgsxr wrote: »

You can't it defys physics.

It could possibly be a given that you or me do not know how a man landed on the moon, it also defied physics but a man did land there.

Boyle's Law is basic secondary school physics. If you cannot understand this principle, it is really not my place to continue this as it is going nowhere. Perhaps this information should be kept in a far far place and the moral of the storey is, anybody not understanding the principles of unvented cylinder installations should really leave them to persons who do.

jimstir

Hi Guys, I just got my copper cylinder replaced. I'm wondering what to do with the old one. Does anyone know a legitimate place in Limerick or Galway that I can bring it to get a few bob for it? It's a standard one from the 1980s about 1m high. Anyone have a rough idea what it's worth?

corkgsxr

shane0007 wrote: »

You are still not reading my post!



I should get paid for this! Look it up, Boyle's Law, that is.....

Increase the temperature and you get a increase in volume and pressure.

You increase the volume of the cylinder your not increasing the pressure (expansion vessel) so you won't a increase of heat. You need to increase of both to get heat. And small amounts at that


Besides all this my point of it being safe is based on a pressure/temperature relief valve keeping temperature below 90 degrees. If temperature stays below 90 degrees its just a very hot tap. It can't go to steam.

corkgsxr

corkgsxr wrote: »

So can you explain how you can get over 100 degree when your heat source can't go over 100 degrees.

You can't it defys physics.

If it can't get over 100 degrees it won't turn to steam out the taps.

And all this is still ignoring a pressure/temperature relief that will keep temperature below 90 degrees.

I work for a manufacture of unvented cylinders, it's me that goes out across this country to inspect, identify and repair, even a slow learner like me is going to pick up a bit over 10 years plus I have my G3 which I resit every 5 years so I get it, you don't, seriously, if you are working on unvented cylinders do a course.

A couple of years ago I went to a call where the T/P was not fitted and a cap was in its place, so when I see a question like " your ignoring the T/P valve" i have a little chuckle cos in all honesty it's not me forgetting I'm worried about, it's the bloody installer forgetting I'm worried about

corkgsxr

shane0007 wrote: »

You can.




They can fail, they can stick and oh yeah, Fruitloops can blank them, which is more often the case!

Fail yes but usually get weaker, ie less temperature or less pressure.

And fruitloops can do a lot to make things dangerous, they could blank the feed and expansion on the stove making it pressurised, are you accountable to that

corkgsxr

gary71 wrote: »

I work for a manufacture of unvented cylinders, it's me that goes out across this country to inspect, identify and repair, even a slow learner like me is going to pick up a bit over 10 years plus I have my G3 which I resit every 5 years so I get it, you don't, seriously, if you are working on unvented cylinders do a course.

A couple of years ago I went to a call where the T/P was not fitted and a cap was in its place, so when I see a question like " your ignoring the T/P valve" i have a little chuckle cos in all honesty it's not me forgetting I'm worried about, it's the bloody installer forgetting I'm worried about

You say one fitted with a t/p is dangerous because someone might forget to fit one.

I agree one without one is dangerous. No arguments there. My point is with one fitted it makes it safe.

corkgsxr

corkgsxr wrote: »

Besides all this my point of it being safe is based on a pressure/temperature relief valve keeping temperature below 90 degrees. If temperature stays below 90 degrees its just a very hot tap. It can't go to steam.

The manufactures who make the cylinder belive there can be a problem with steam and expect the discharge pipe to be designed specifically for safety , then the fact every single unvented installation in the UK has to be inspected before it can be used and every installer must prove he understands the dangers by passing a safety exam before dealing with unvented cylinders, all of that then there's you who says it can't happen, you could be right but I'm going to keep sticking to the MI thank you:D.

JohnnieK

Another simple thread that was started by someone with a simple question is dragged into the gutter.

What is this forum coming to.

jca

JohnnieK wrote: »

Another simple thread that was started by someone with a simple question is dragged into the gutter.

What is this forum coming to.

+1

corkgsxr

JohnnieK wrote: »

Another simple thread that was started by someone with a simple question is dragged into the gutter.

What is this forum coming to.

a can ya not have a debate at all.

Had a look at environ regs, you can't have gravity circuit to unvented cylinder.

Still maintain the idea is sound maybe too easy to mess with or do wrong.

gifted

JohnnieK wrote: »

Another simple thread that was started by someone with a simple question is dragged into the gutter.

What is this forum coming to.

I log onto this forum with me popcorn now...waiting for the bitching to start..:D

Dardania

To be honest, I found this thread extremely informative. Never connected the dots that if one keeps pumping heat into a cylinder, the pressure will rise... I also allegedly studied Boyle's law in school, but damned if I could remember it until now! I always worked on the principle that there must be a tmeperaure differential before heat transfer will occur...

One idea that occured to me was: in Britian is it possibly the norm to have higher incoming mains water pressure to cylinders, possibly lending to pressure problems as discussed? I had seen around the internet that their mains could be 2 to 4 bar, now I don't know if they typically have that in an attic storage tank, or if it goes directly to the calorifier...

Dardania

Dardania wrote: »

in Britian is it possibly the norm to have higher incoming mains water pressure to cylinders, possibly lending to pressure problems as discussed? I had seen around the internet that their mains could be 2 to 4 bar...

Unvented cylinders come with a combination valve which has incorporated in it a 3 1/2 bar pressure reducing valve, so the maximum pressure feeding a cylinder should be 3 1/2 bar, it's the same for under sink water heater but pressure reducers are rarely fitted leading to big insurance payouts for the installer.

Dardania

gary71 wrote: »

Unvented cylinders come with a combination valve which has incorporated in it a 3 1/2 bar pressure reducing valve, so the maximum pressure feeding a cylinder should be 3 1/2 bar, it's the same for under sink water heater but pressure reducers are rarely fitted leading to big insurance payouts for the installer.

Does the pressure reach that high in Ireland? My gravity fed cylinder probably hits all of 0.1bar at cold...

Dardania

Dardania wrote: »

Does the pressure reach that high in Ireland? My gravity fed cylinder probably hits all of 0.1bar at cold...

It's dependant on the installation/area, there are areas over 4 bar, there is a format for installing unvented and if followed there is less heartache.

Dardania

Dardania wrote: »

My gravity fed cylinder probably hits all of 0.1bar at cold...

Gravity and mains are different, gravity is dependent on the hight of the tank also gravity installations have different installation requirements.

Dardania

gary71 wrote: »

It's dependant on the installation/area, there are areas over 4 bar, there is a format for installing unvented and if followed there is less heartache.

In your experience, are there many installations in Ireland with 4 bar to the cylinder? I thought you weren't meant to connect mains to the cylinder...but I thought that was because the local authorities want us to have 2 hours storage...

There's always the incidence of a booster pump before the cylinder...which could happen anywhere

gary71 wrote: »

Gravity and mains are different, gravity is dependent on the hight of the tank also gravity installations have different installation requirements.

would you have any links to the guidance notes for this? I'm working on the LPHW in my home at the moment, and just want to check that all I am doing is kosher...

kscobie

Redwid wrote: »

Hi all,

I'm looking for replacement to my old hot water cylinder that is small (about 1 m in height) and doesn't have a pump.

Does anybody could recommend any supplier and installers to me?

And it started with a simple question ..!

shane0007

kscobie wrote: »

And it started with a simple question ..!

Ah, that it did, but is this type of thread not what Boards is all about?

The original question was answered and a more entertainment factor was thrown in. After all, Gifted would be very disappointed if the thread was had not been extended! In fact, he may even stop logging in!