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I have a couple of stupid questions. (Actually, more than a couple, it turns out).
Firstly, PTFE tape. Is it worth it (a lot of people recommend it; but many say it makes no difference. Who is right)? Is it stable enough to be used on the piping for the default radiator? What about the fittings on the back of the stove? Intuitively it seems to me that no part of the stove directly connected to water should ever get above 100 degrees, so PTFE tape would be okay. Is that right?
Secondly, one of the plumbers we had in to quote suggested that we could handle filling the system, and dealing with overflow due to expansion, by teeing off from the default radiator flow piping, into a small tank with a ball-cock inlet, and overflow pipe outlet.
That seems entirely reasonable, but I've never seen anyone else suggest it.
Am I missing something?
 
Firstly PTFE is the best thing if used correctly on male threads such as radiator tails and boiler/cylinder & tank tappings It has to be wound round a good few turns the correct way clockwise so it does not strip off when tightening the joint up. A Lot of amateurs use it on compression fittings but that is not needed and can infact be a bad thing.

Secondly You should already have a vent for expansion! what are you trying to achieve? and what kind of system do you have? Or is this a new install?
 
Firstly PTFE is the best thing if used correctly on male threads such as radiator tails and boiler/cylinder & tank tappings It has to be wound round a good few turns the correct way clockwise so it does not strip off when tightening the joint up. A Lot of amateurs use it on compression fittings but that is not needed and can infact be a bad thing.

Secondly You should already have a vent for expansion! what are you trying to achieve? and what kind of system do you have? Or is this a new install?
Okay, with respect to PTFE, I was advised to use it on compression joints - why is it wrong?
The system is a new one - the diagram I have from the stove manufacturer has a vent on the flow, and an inlet tank on the return - the plumber I had in to quote for installation suggested that I combine the two, tee off from the inlet with an overflow into the tank; but I can't see a reason to do that except that the inlet tank might reach the temperature of the flow feed rather than the return feed.
I can post a diagram if that would help.
 
Compression joints only need to be tightened up by hand and then usually just need say and extra half a turn to nip up the olive and do not need any PTFE on them at all, if there is a little weep on it then just give it another quarter turn with your spanner. Overtightening a compression fitting will crush the olive and it will leak. Using PTFE on a compression joint is not good practice although we come across it all the time usually because it is leaking and we've been called out to it,

Always follow the Mi's to the letter if they show it on a diagram how they want it doing, then have it done just like that. Deviating away from the Mi's could be dangerous & invalidate any warranties and leave you up the creek!
 
Compression joints only need to be tightened up by hand and then usually just need say and extra half a turn to nip up the olive and do not need any PTFE on them at all, if there is a little weep on it then just give it another quarter turn with your spanner. Overtightening a compression fitting will crush the olive and it will leak. Using PTFE on a compression joint is not good practice although we come across it all the time usually because it is leaking and we've been called out to it,

Always follow the Mi's to the letter if they show it on a diagram how they want it doing, then have it done just like that. Deviating away from the Mi's could be dangerous & invalidate any warranties and leave you up the creek!


I've always been told about overtightening olives but so far I've only managed to crack a few nuts never had a smashed olive.
 
If it's an uncontrolled heat source, e.g. a woodburning stove with a backboiler and with manual or thermostatic controls and not a computer and electronic devices etc., and your installer is suggesting you combine the vent and cold feed, then you really need to find another installer. One with HETAS or OFTEC (or equivalent) wet heating systems solid fuel competent person registration would be best - then you don't need to inform Building Control. The one you have is giving dangerous advice.

Combined vent and feed is a safety compromise and ONLY acceptable where the manufacturer has specifically stated that a combined feed and vent is acceptable practice, usually because the boiler itself incorporates advanced safety devices.

PTFE: yes, it's alright on screwed joints. Hemp and paste is better though (not suited for drinking water), Loctite 55 is also very good, easier to use, more reliable than PTFE, and can also be used on drinking water. For an amateur who doesn't need a tin of paste going hard, I'd say Loctite 55 is the best.

PTFE on compression (just a couple or so of turns on top of (i.e. around) the olive) can work as a temporary measure where there is a buggered overtightened olive causing a weep (installed by others) and it's 5 o'clock and you want to get the water back on for the weekend prior to a proper repair on Monday. That's when I'd use it myself.

Don't use it on the threads of a compression joint EVER. I note Anglian Water subcontactors seem to like to put it around the olives and I wouldn't say it's wrong. But it's not pretty and I wouldn't put my name to it as a permanent installation for that reason.
 
Compression joints only need to be tightened up by hand and then usually just need say and extra half a turn to nip up the olive and do not need any PTFE on them at all, if there is a little weep on it then just give it another quarter turn with your spanner. Overtightening a compression fitting will crush the olive and it will leak. Using PTFE on a compression joint is not good practice although we come across it all the time usually because it is leaking and we've been called out to it,

Always follow the Mi's to the letter if they show it on a diagram how they want it doing, then have it done just like that. Deviating away from the Mi's could be dangerous & invalidate any warranties and leave you up the creek!
Thanks for the advice - I think I've been overtightening my compression joints so far - I'll tone it down for this project. As to warranties, it's a second hand stove, so there are none :-(
 
Thanks for the advice - I think I've been overtightening my compression joints so far - I'll tone it down for this project. As to warranties, it's a second hand stove, so there are none :-(
So installing it without any instructions could be a big mistake as it seems both you and your 'Plumber' don't have much of an clue and are guessing at things
 
If it's an uncontrolled heat source, e.g. a woodburning stove with a backboiler and with manual or thermostatic controls and not a computer and electronic devices etc., and your installer is suggesting you combine the vent and cold feed, then you really need to find another installer. One with HETAS or OFTEC (or equivalent) wet heating systems solid fuel competent person registration would be best - then you don't need to inform Building Control. The one you have is giving dangerous advice.

Combined vent and feed is a safety compromise and ONLY acceptable where the manufacturer has specifically stated that a combined feed and vent is acceptable practice, usually because the boiler itself incorporates advanced safety devices.
I don't understand the difference between what the manufacturer is proposing, and what the plumber suggested. In either case the heating system can handle expansion due to heat. I've attached two files, the more complex one is what the manufacturer recommends, the other is what our plumber suggested.

heating system version 2.png


heating system.png
 
Compression joints only need to be tightened up by hand and then usually just need say and extra half a turn to nip up the olive and do not need any PTFE on them at all, if there is a little weep on it then just give it another quarter turn with your spanner. Overtightening a compression fitting will crush the olive and it will leak. Using PTFE on a compression joint is not good practice although we come across it all the time usually because it is leaking and we've been called out to it,

I beg to differ, compression fittings with brass olives definitely need either a smear of paste or a wrap or two on the meeting face of the olive ti that of the face of the fitting.
As a matter of fact I don’t know of any old school time served plumber that doesn’t paste or wrap the olive. Fittings are terrible these days ,that you need a helping hand to just about guarantee a decent joint.
 
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Your plumber is an idiot.
Do NOT use that guy to plumb your stove!
Open vent gravity circuit solid fuel systems need a feed from return primary and a vent pipe from flow primary and each 22mm minimum. Both also act as safety vents
Sounds to me your plumber never has done any solid fuel work before.
For compression olives you need paste and for male threads into rads and boiler ptfe tape used correct amount of turns is absolutely fine and in my opinion some paste on the taped joint will also help.
Ptfe can take any heat a heating system can put on it.
Hope you are not going to do the solid fuel work yourself?
 
Paste for me as well
 
Paste can help. Never PTFE on compression. Amateurish DIY practice. I am time served and do not use pasts unless absolutely necessary. PTFE is for threaded joints only.
 
Your plumber is an idiot.
Do NOT use that guy to plumb your stove!
Open vent gravity circuit solid fuel systems need a feed from return primary and a vent pipe from flow primary and each 22mm minimum. Both also act as safety vents
Sounds to me your plumber never has done any solid fuel work before.
For compression olives you need paste and for male threads into rads and boiler ptfe tape used correct amount of turns is absolutely fine and in my opinion some paste on the taped joint will also help.
Ptfe can take any heat a heating system can put on it.
Hope you are not going to do the solid fuel work yourself?
I am, yes. That's why I wanted the advice. I don't see why it makes a difference, but I'm going to re-design what I had planned to conform with their design.
 
What get’s forgotten is that stoves are notifiable like any other heating appliance and that the work should be carried out by a competent person. This is for obvious reasons espially since it’s uncontrolled nature. The fashionable trend of having solid fuel appliances I am sure will contribute to an upward trend of self inflicted accidents which will cause eventually for the enforcement side to catch up. Good luck
 
I've always been told about overtightening olives but so far I've only managed to crack a few nuts never had a smashed olive.
i have had a couple of jobs over the years where they were so tight (brass olives) that they cut into the pipe, causing leaks
 
What get’s forgotten is that stoves are notifiable like any other heating appliance and that the work should be carried out by a competent person. This is for obvious reasons espially since it’s uncontrolled nature. The fashionable trend of having solid fuel appliances I am sure will contribute to an upward trend of self inflicted accidents which will cause eventually for the enforcement side to catch up. Good luck
"stoves are notifiable like any other heating appliance".
Can you explain this?
 
Stove installations are classed as a “controlled service” and therefore installation of a solid fuel burning appliance such as what you proposed is included. Compliance is required which includes notification to building control either by the building owner if carrying out the work themselves or on behalf of the owner by a competent person on a register. I would urge you to read Document J of the Regs. Link included.

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/468872/ADJ_LOCKED.pdf
 
Yes I thought by your posts that you were going to do the work.
Probably unwise.
 
What's that saying?
'There's no such thing as a stupid question'

There are exceptions to every rule - and this thread is an exception to that rule.
 
Yes, basically a stove should be installed either by a registered competent person or notified to building control if installed by anyone else.
My neighbour has a wood burning stove installed by her father'. How he carried out a leakage test on the 150-year-old chimney when adapting it from open fire to closed appliance without asking to come into my house to check the other side of the chimney is anyone's guess (I'm guessing he didn't), and, of course, it could result in the death of his daughter, or of myself. To be honest, I couldn't care less if he notified the work or not, but I do wish he'd stop bodging things.
The one saving grace with stoves is that a leaking flue mostly makes the room smell of smoke, so although you may not be able to smell carbon dioxide, you can at least usually smell the smoke itself. That said, much better to do the job properly (and legally) than run risks.
For what it's worth, I see differences between what the plumber is suggesting and what the manufacturers state. If your plumber thinks his solution will be satisfactory in the long run (or at all), I still think you need to find another plumber.
Do you even have a plumber, or by your plumber, do you mean yourself?
 
If it's an uncontrolled heat source, e.g. a woodburning stove with a backboiler and with manual or thermostatic controls and not a computer and electronic devices etc., and your installer is suggesting you combine the vent and cold feed, then you really need to find another installer. One with HETAS or OFTEC (or equivalent) wet heating systems solid fuel competent person registration would be best - then you don't need to inform Building Control. The one you have is giving dangerous advice.

Combined vent and feed is a safety compromise and ONLY acceptable where the manufacturer has specifically stated that a combined feed and vent is acceptable practice, usually because the boiler itself incorporates advanced safety devices.

PTFE: yes, it's alright on screwed joints. Hemp and paste is better though (not suited for drinking water), Loctite 55 is also very good, easier to use, more reliable than PTFE, and can also be used on drinking water. For an amateur who doesn't need a tin of paste going hard, I'd say Loctite 55 is the best.

PTFE on compression (just a couple or so of turns on top of (i.e. around) the olive) can work as a temporary measure where there is a buggered overtightened olive causing a weep (installed by others) and it's 5 o'clock and you want to get the water back on for the weekend prior to a proper repair on Monday. That's when I'd use it myself.

Don't use it on the threads of a compression joint EVER. I note Anglian Water subcontactors seem to like to put it around the olives and I wouldn't say it's wrong. But it's not pretty and I wouldn't put my name to it as a permanent installation for that reason.
I understood hemp and paste is not suitable for gas, as it's slightly permeable, not enough for a explosion risk, but to smell nasty. (I know this thread is not about gas)
 
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