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[ASIDE: I did wonder if this was the best forum for this but figured as it was a boiler related issue that the gas engineers would be dealing with it as a matter of course. If I'm wrong can someone let me know and I'll shift it to a better place.]
I have a condensing boiler installation which is working fine in its main function. It is a Vaillant boiler with a grey short flexible corrugated drain pipe feeding from its underside. This is about 4 inches or so and joins onto a standard white 21.5mm downpipe inside the house. This mates with an unsealed push in rubber reducer as the air gap. Then it travels through the wall to the outside and down to a soakaway well away from the house foundations. It froze up during the winter so we fitted it with an insulated and sleeved system in its outside section. That outside piping all works just as it should.
I noticed that where the 21.5mm pipe entered the rubber bung at its lower end there was a very slight ring of water appearing around the junction. At first I worried that it had been blocked or kinked in some way but there are no problems there. I found the problem at, to me at least, a surprising point. The problem I have is at the top of the indoor 21.5mm pipe where the dedicated short boiler drain pipe fits onto it. This has the downward running Vaillant pipe over the outside of the 21.5mm pipe so it relies on that push on joint being watertight. It obviously isn't.
I'm amazed that the boiler pipe is the female and sits over the end of the other as it travels downwards. It must have been better to mate it to the 21.5mm pipe via a straight coupler solvent welded to the lower pipe only and size it so it could sit inside without restricting the inner area in any way.
I am loathe to solvent weld a not immediately available part like that to the common or garden pipe so I'm looking for the "correct" solution to this. I have considered flaring the end of the 21.5mm pipe so the other sits inside of it. I could also flare the end of a straight coupler as that would need less freedom. How is this normally handled? Is that "inverted" push on fit the usual way? Does it not lend itself to this problem at some stage?
I do know that the boiler pipe, being an awkward plastic type, would need a special two part adhesive if it came to it. One prepares the surface to accept and bond to the second adhesive paste. I have this available from the insulated pipe install which is the same type. Although, maybe the answer is as simple as a gob of Boss White or even a jubilee clip?
I have a condensing boiler installation which is working fine in its main function. It is a Vaillant boiler with a grey short flexible corrugated drain pipe feeding from its underside. This is about 4 inches or so and joins onto a standard white 21.5mm downpipe inside the house. This mates with an unsealed push in rubber reducer as the air gap. Then it travels through the wall to the outside and down to a soakaway well away from the house foundations. It froze up during the winter so we fitted it with an insulated and sleeved system in its outside section. That outside piping all works just as it should.
I noticed that where the 21.5mm pipe entered the rubber bung at its lower end there was a very slight ring of water appearing around the junction. At first I worried that it had been blocked or kinked in some way but there are no problems there. I found the problem at, to me at least, a surprising point. The problem I have is at the top of the indoor 21.5mm pipe where the dedicated short boiler drain pipe fits onto it. This has the downward running Vaillant pipe over the outside of the 21.5mm pipe so it relies on that push on joint being watertight. It obviously isn't.
I'm amazed that the boiler pipe is the female and sits over the end of the other as it travels downwards. It must have been better to mate it to the 21.5mm pipe via a straight coupler solvent welded to the lower pipe only and size it so it could sit inside without restricting the inner area in any way.
I am loathe to solvent weld a not immediately available part like that to the common or garden pipe so I'm looking for the "correct" solution to this. I have considered flaring the end of the 21.5mm pipe so the other sits inside of it. I could also flare the end of a straight coupler as that would need less freedom. How is this normally handled? Is that "inverted" push on fit the usual way? Does it not lend itself to this problem at some stage?
I do know that the boiler pipe, being an awkward plastic type, would need a special two part adhesive if it came to it. One prepares the surface to accept and bond to the second adhesive paste. I have this available from the insulated pipe install which is the same type. Although, maybe the answer is as simple as a gob of Boss White or even a jubilee clip?
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