Flexi joints in 28mm pipe

[Smelly]

I'm having problems with the joints on our central heating. They're currently 25mm engine hose flexed over an olive on the end of the 28mm pipe and jubilee clipped in place, however when we let the fire go out over the weekend everything contracted apart from the jubilee clips, which had opened up a tad and we had a significant leak... If we'd remembered to switch the water pump off before leaving there might not have been quite so much water in the cabin bilge but that's a different story.

 

I've been chasing weepy leaks since October but it got serious this weekend.

 

Where I've had to dismantle joints I've used liquid PTFE that might help but see this as a temporary fix; I need to re-think the jointing completely.

 

I've considered using 28mm pipe benders to form the bends but this would be awkward considering the pipe layout, and I'd like to use some form of flexible joint however don't know of an alternative and available solution. Any ideas or suggestions would be appreciated.

 

On idea is something i've seen at the local DWP medical examination centre... Where the walls have distorted they've used some form of crenellated pipe that means the pipes don't need to be exactly in line, but I don't know whether they'd form a decent 30 degree bend although they look like they might. I don't know who might supply them either as I can't see them in the BES catalogue.

[blackrose]

Why don't you use 90 deg, 28mm compression fittings? Or even better, if it's a thermosyphon system with no pump and you want to facilitate good flow you could use 2 x 135 degree compression fittings for each 90 degree bend.

 

Edit: sorry, I just realised you have a pump!

 

Double edit: Why do the bends have to be flexible? (You're obviously not looking for 90 degree bends?)

Edited November 30, 2009 by blackrose

[Timleech]

Often two hose clips with the screws on opposite sides of the pipe can help in that sort of situation.

 

Tim

[blackrose]

I heard that the viscosity of water is greatly reduced once antifreeze/coolant is added, leading to these sorts of problems.

 

Mind you, you have invented a rather unorthodox joint!

[Smelly]

Often two hose clips with the screws on opposite sides of the pipe can help in that sort of situation.

 

Tim

 

Thank you.

 

I'd still hope for a more mechanical situation, unless I can come up with a slightly wider hose. It's a pig, even lubricated with PTFE to get the hose far enough up to securely fasten one clip, never mind two, but will certainly take heed.

[RLWP]

Thank you.

 

I'd still hope for a more mechanical situation, unless I can come up with a slightly wider hose. It's a pig, even lubricated with PTFE to get the hose far enough up to securely fasten one clip, never mind two, but will certainly take heed.

 

My only experience of those corrugated flexible pipes is in my sister's bathroom. They burst and brought down the ceiling below. And that was in a situation where they were only flexing because of pressure changes.

 

I can't see that what you are trying to do originally is that extreme. Perhaps you just need to replace the hoses as they have hardened and cracked with age.

 

Richard

[Smelly]

My only experience of those corrugated flexible pipes is in my sister's bathroom. They burst and brought down the ceiling below. And that was in a situation where they were only flexing because of pressure changes.

 

I can't see that what you are trying to do originally is that extreme. Perhaps you just need to replace the hoses as they have hardened and cracked with age.

 

Richard

 

They're only two years old and the bit I replaced yesterday is in decent fettle...

[Smelly]

Why don't you use 90 deg, 28mm compression fittings? Or even better, if it's a thermosyphon system with no pump and you want to facilitate good flow you could use 2 x 135 degree compression fittings for each 90 degree bend.

 

Edit: sorry, I just realised you have a pump!

 

Double edit: Why do the bends have to be flexible? (You're obviously not looking for 90 degree bends?)

 

No pump, pipes running through bulkheads flush to the wall with very little space to play with. However it might just be doable looking at the system. Perceived problem may be getting enough grip on the joints to tighten them up.

 

don't know about unorthodox, I've seen a couple of Kelvins with similar altough thinking about it they've got two jubilee clips on each joint... hmmm!

[steelaway]

I can only see pipes to 22mm but these might work

 

 

Alex

[bag 'o' bones]

Our set-up:

 

[blackrose]

Our set-up:

 

 

A picture paints a thousand words. Is your point that even quite convoluted pipework can be fitted with rigid joints?

 

I tend to agree and I can't help thinking that unless Smelly can find some 28mm push fit tap connectors, any home made flexible joint will always be a botch.

 

But who knows, he may come up with something.

 

Here's a thought:

 

My header tank is connected with car heater hose which comes off the top run of the system via a 28mm T compression connected to a short piece of copper pipe which then goes onto another compression, a threaded fitting and a big brass hosetail. Its never leaked.

 

Your problem seems to be that you're trying to put the hose over pipe, but if you could somehow connect hosetails to each end of the joint then your jubilee clips should clamp up properly.

 

Just an idea.

Edited November 30, 2009 by blackrose

[Big COL]

I'm having problems with the joints on our central heating. They're currently 25mm engine hose flexed over an olive on the end of the 28mm pipe and jubilee clipped in place, however when we let the fire go out over the weekend everything contracted apart from the jubilee clips, which had opened up a tad and we had a significant leak... If we'd remembered to switch the water pump off before leaving there might not have been quite so much water in the cabin bilge but that's a different story.

 

I've been chasing weepy leaks since October but it got serious this weekend.

 

Where I've had to dismantle joints I've used liquid PTFE that might help but see this as a temporary fix; I need to re-think the jointing completely.

 

I've considered using 28mm pipe benders to form the bends but this would be awkward considering the pipe layout, and I'd like to use some form of flexible joint however don't know of an alternative and available solution. Any ideas or suggestions would be appreciated.

 

On idea is something i've seen at the local DWP medical examination centre... Where the walls have distorted they've used some form of crenellated pipe that means the pipes don't need to be exactly in line, but I don't know whether they'd form a decent 30 degree bend although they look like they might. I don't know who might supply them either as I can't see them in the BES catalogue.

 

 

Hi

 

Not too difficult to overcome. Have two high pressure water pipes or steam pipes made with 1" or 1 1/4" BSP or 28mm male, female ends whichever is easiest. There are lots of hydraulic hose companies that will knock up a set of pipes in about 1/2 hour.

Edited November 30, 2009 by Big COL

[ditchcrawler]

No pump, pipes running through bulkheads flush to the wall with very little space to play with. However it might just be doable looking at the system. Perceived problem may be getting enough grip on the joints to tighten them up.

 

don't know about unorthodox, I've seen a couple of Kelvins with similar altough thinking about it they've got two jubilee clips on each joint... hmmm!

I take it you have lubricated the worm threads and that you are using a socket spanner and not a screw driver to tighten them

[bag 'o' bones]

A picture paints a thousand words. Is your point that even quite convoluted pipework can be fitted with rigid joints?

I tend to agree and I can't help thinking that unless Smelly can find some 28mm push fit tap connectors, any home made flexible joint will always be a botch.

 

But who knows, he may come up with something.

 

Something like that.......

[Smelly]

Something like that.......

 

Moving the fire so that it's 45 degrees to the corner may well be a good idea. It'll mean a new flue but will give a lot more play in the pipe work...

[bag 'o' bones]

Moving the fire so that it's 45 degrees to the corner may well be a good idea. It'll mean a new flue but will give a lot more play in the pipe work...

 

Funnily enough we were talking about it today. Our stove sticks out from the wall more than most, simply because we believe that a lot of builders site the stoves without any consideration for future maintainance or even any regard for safety in certain cases. For example building the stove into the corner next to the steps - flues make great hand holds! NOT! The only thing we may have changed is rather than site the stove exactly 45 degres from the wall would be to increase the angle to something like 110 degrees pointing down the boat (hope that makes sense) Still having said that there are for and against for that set up so were still quite happy with 45 degrees.

[Smelly]

I think there's been a misunderstanding here...

 

The pipework rises from the joints on the boiler at angles other that 90 or 45 degrees. The pipes also tee out of the back of the fire and; the fire being in the middle, I've not been able to site a 45 degree bend, that would need the connections from the fire to be at perfect angles, which they aren't

 

I am compelled to fasten t joints to the back of the fire to supply both sides and need to compensate for the rise in both pipes. Fair enough i could move the fire a few inches further in to compensate for the extra pipework behind the fire but I'd rather not; hence my question about flexi joints...

[RLWP]

With two 45 degree bends and a bit of pipe between them you can make any angle you want. Is that piece of knowledge of any help to you?

 

Richard

[alan_fincher]

With two 45 degree bends and a bit of pipe between them you can make any angle you want. Is that piece of knowledge of any help to you?

 

Richard

I'd like 135 degrees,please !

[sharpness]

They're currently 25mm engine hose flexed over an olive on the end of the 28mm pipe and jubilee clipped in place,

 

The hoses for our calorifier are done like this in 15mm copper. I presume the olives are soldered onto the copper pipe???

 

Steve

[wonderdust]

I would say compressed, then the nut slid of the other end.

[smileypete]

I'm having problems with the joints on our central heating. They're currently 25mm engine hose flexed over an olive on the end of the 28mm pipe and jubilee clipped in place, however when we let the fire go out over the weekend everything contracted apart from the jubilee clips, which had opened up a tad and we had a significant leak... If we'd remembered to switch the water pump off before leaving there might not have been quite so much water in the cabin bilge but that's a different story.

 

I've been chasing weepy leaks since October but it got serious this weekend.

 

Where I've had to dismantle joints I've used liquid PTFE that might help but see this as a temporary fix; I need to re-think the jointing completely.

 

I've considered using 28mm pipe benders to form the bends but this would be awkward considering the pipe layout, and I'd like to use some form of flexible joint however don't know of an alternative and available solution. Any ideas or suggestions would be appreciated.

 

On idea is something i've seen at the local DWP medical examination centre... Where the walls have distorted they've used some form of crenellated pipe that means the pipes don't need to be exactly in line, but I don't know whether they'd form a decent 30 degree bend although they look like they might. I don't know who might supply them either as I can't see them in the BES catalogue.

A photo might help.

 

Maybe the jubilee clip wasn't quite tight enough.

 

For sealing a troublesome joint like that I'd use a smear of Fernox LS-X leak sealer (what is 'liquid ptfe'...?)

 

cheers,

Pete.

[bag 'o' bones]

Just for the record it good practice to use proper branded Jubilee clips (or a good alternative)rather than one from a £1.99 pack off the market. Cheap clips usually have weak grub screw threads which have a habit of slackening off.

 

Also it is important to use the correct size too, winding them up to their minimum size forms a pinch which usually ends up leaking.

 

Over tightening is almost as bad as undertightening. If the hose needs a lot of whelly to stop it weeping then more othen and not the rubber has become hard and brittle. Time for a new hose......

 

A smigen of vaseline on the threads will stop the grub screw seizing in the future.

Edited December 2, 2009 by bag 'o' bones

[Smelly]

Sorry for a lack of response but dose of head and a*se has been the order of the day.

 

The olives are compressed on and the joint taken off the other end. The Jubliee clips are from Midland Swindlers so I reckon they're sound, 2 45 degree bends is a useful bit of advice and thank you.

 

So long as the system survives Xmas I think that it will get re-built next year with entirely soldered joints to replace the hose. I'm skeptical of putting a rigid system such as that in place, as it will prove harder to fix when the soldered joints fail, and I can't find 28mm angles so will need to drop to 22mm and form the pipe bends with a spring for the angles, however a different design is necessitated methinks.

 

I worry about even short lengths where the the pipe dia is reduced, as at least in heat distribution it works very well and I'm shy of disturbing that however needs must.

 

I'm still tempted by those crenelated pipes though...

[johnjo]

28mm plastic push fit to copper fitting at screwfix, any good for you 'Smelly' ?

 

The plastic pipe is reasonably flexible when heated up in hot water.

 

Scroll 3/4 of the way down the page.

 

http://www.bizrate.co.uk/plumbingsupplies/...3--688367-.html

 

Edited to correct link.

Edited December 4, 2009 by johnjo