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How can high pressure steam be produced when the tap is open
hi tom introduce yourself here New Member Introductionshi everyone i'm new to the site i agree with dancin on this will be ok
the ch side is still full of water and will dissipate the latent heat in the hexbut you just hit the nail on the head there, mains is off as the tap is leaking so its not at mains pressure, so water can boil at 100 deg c and lack of water can let it boil, produce steam which can be quite high pressure which can also damage the o rings and cause leaks. Hence why all low water content boiler have overrun to cool the hex to prevent hot spots etc cooking them. So the only one spouting rubbish is milsy
How can high pressure steam be produced when the tap is open
or a juniorwould any of the leave it its ok, who have a ferrolli like this at home, pop out and set it up to see what happens in this situ and let us know pse
sorry but your wrong,end of argument,as said this boiler has a twin pass heat exchanger,there is a risk that remnants of water left in the domestic side can cause issues if the ch is used,now who has the balls to argue differently with me about boiler design??? i am not taking anyones side but this is FACTThere is no way that the boiler firing up for heating is going to cause any damage to the heat exchanger because the DHW side is empty The pump will run and this will take the heat out of the boiler. Yes there is still going to be water in the DHW side but at zero pressure it will not build up so drastically that it is going to cause damage to the heat ex. As for the OH stat it will also cut the boiler out on the DHW side of things as well as the heating it is a safety feature that will shut the boiler off when heat exchanger gets to a set temperature. It will not do any thing to the potentiometer as every OH stat I have ever come across in the 14 years I have worked in this trade work the same they go from closed to open circuit.
I have left many peoples heating running in the past whilst I have had the water off changing taps etc and surprise surprise I have never killed anybodys heat exchanger. I would suggest Lame plumber that you do not comment on things you are 100% sure of as in this case you are definately sprouting rubbish.
nothing to do with the dhw side then ??we can all have an opinion, but there's no need to be rude, after all forums are for discussion and everyone has had different experience of boilers and problems and because of issues I have had, esp with a ferrolli in the past I offered my opinion such that the bloke posting a query could make a choice. Like I said, I've experienced a ferrolli doing just this when I failed to bleed a pump thro recently, it only wrecked a couple of o rings but when chris from ferrolli turned up, he was decent enough to point out loads of his work involves repairing boilers where the hex is boiled and o rings blown and flow valves melted, and with that damage pcbs etc knackered. This is being done regularly on new installs so there is the potential to do the same with this boiler if your luck runs out so why risk it. So as you tried to say, you shouldnt comment on things you are not 100% sure of, but in this case I'm 98% sure so I think I can offer an opinion without being told I'm sprouting, sorry spouting a lot of rubbish. If you want to comment, please feel free, its an open forum but dont get arsy as its not really needed. After all the guy only wants an opinion to make his choice! be it yours or mine or someone elses
how and why ?sorry but your wrong,end of argument,as said this boiler has a twin pass heat exchanger,there is a risk that remnants of water left in the domestic side can cause issues if the ch is used,now who has the balls to argue differently with me about boiler design??? i am not taking anyones side but this is FACT
the domestic circuit runs through but not in direct contact with the primary circuit(ch) the hex is a direct heat design,as apposed to the plate heat set up that is a indirect heat design,take a polystyrene cup,put a tiny amount of water in it and place your gas lamp on full and torch the bottom,you then get some idea of what your doing to a twin pass heat exchanger when running it in heating mode with no water in the secondary (dhw) circuit only in this cup the water quickly evaporates and the cup melts,in a boiler the small amount of water turns to steam melting o rings,the plastic gubbins of the flow switch,and very quickly the copper tubes within the heat exchangerhow and why ?
Still don't understand the above ?the domestic circuit runs through but not in direct contact with the primary circuit(ch) the hex is a direct heat design,as apposed to the plate heat set up that is a indirect heat design,take a polystyrene cup,put a tiny amount of water in it and place your gas lamp on full and torch the bottom,you then get some idea of what your doing to a twin pass heat exchanger when running it in heating mode with no water in the secondary (dhw) circuit only in this cup the water quickly evaporates and the cup melts,in a boiler the small amount of water turns to steam melting o rings,the plastic gubbins of the flow switch,and very quickly the copper tubes within the heat exchanger
YouTube:77:........
here hereLets all just agree to disagree but we were right and you were wrong? Sounds fair to me
i have and here they are for your perusalLets get this straight, has anyone checked the MI's? I have. This boiler does not have a seperate plate heat exchanger. Its heat exchangers HTG + DHW are both located above an atmospheric burner. So when it calls for HTG it also heats the DHW side regardless of DHW demand. So if the DHW side become empty through evaporation because the water is turned off then the consequences could cause damage.
Agree with everyone if it had a seperate plate heat exchanger heated from the main HTG heat exchanger through a diverter valve. Which is the normal for all your Vaillants, Worchesters ect, but not for an old ferrolli Modena.
Also agree that the overheat would probably protect it. but would not rely on it as thats your last line of safety device.
hahaha so trueTo be honest, blowing up a Ferroli doesn't sound like such a bad idea anyway
i have and here they are for your perusal
http://www.ferroli.co.uk/wp-content/uploads/brochures/archives/Ferroli%20F30%20B%20Manual.pdf
I have the mi's already and have checked it out, as I said in my previous post.
Anyway its only a problem if the DHW side dries up. so as long as there is water in it no problem.
If this faulty tap is below the boiler do you think it will dry out. So waters off tap is on, even if its above the boiler, what if they turn on the kitchen ho****er tap which is likely to be below the boiler. It will drain the heat exchanger just above the gas burner which is happly burning away because the heatings turned on.
Was not aware the OP has a second boiler that is empty?So would you turn on a boiler with no water in it?
Reply to the thread, titled "Is a combi boiler safe with NO mains cold water? (Urgent)" which is posted in Boiler Advice Forum on Plumbers Forums.
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