Problem with plumbing washer

[S6PNJ]

I've been struggling to get a seal for a few days now ( I'm not constantly trying but keep coming back etc) on a water pipe connection to my water softener.
I've bought new plumbing washers (correct external and internal dims and also width), but can't get get a seal, no matter how tight I do it up. I've tried it loose, then once water is partially connected (and its weeping) tried to tighten it until it stops weeping, but no joy. Are these washers meant to deform to close up the gap as they seem to have a serrated face.

The old washer that came out is deformed (you can see where it has been shaped over the period of installation, and I've also tried to get that one to seal a few times. There is a wter in and water out conenction - the water in works fine with the old washer, but I just can't get this one to seal.

I've tried fitting the washer, tightening it up, then leaving it for a day or so in case it deforms and coses whatever gap is present, but still no luck, always a weep. I've checked the mating faces of the two ends (one metal, one plastic) and they are both flat and true with no dinks or uneven surfaces etc. Just running out of things to try...

Edited by S6PNJ on Sunday 11th May 11:00

[S6PNJ]

2 additional photos

[Mr Pointy]

Is the nut bottoming out on the the male threads & stopping the washer actually being compressed? I 've had that once. Failing that try a different brand/type of washer that isn't dimpled. Last resort - a wipe of Plumber Mait on each face.

[JoshSm]

Rubber or fibre washer? Fibre needs to get wet to swell & seal so some initial weeping isnt unusual.

If rubber not sealing maybe not fitting properly/tightening down fully? Maybe giving it a wipe of silicone grease on the mating faces will help?

Rubber washers are normally tricky to get wrong so I'd try dry assembling without the washer to see if it is bottoming out before it tightens enough to compress the washer.

Edited by JoshSm on Sunday 11th May 11:29

[S6PNJ]

2 quick replies (not a fibre washer, they are rubber):

It's not bottoming out, I've connected it minus the washer and it closes further than when a washer is fitted.

Yes, I've tried a smear of silicon grease on both faces

Also, I've checked the metal areas for any debris caught between the nut and pressure face

[untakenname]

Perhaps try doubling up the washers and use more clamping force?

[S6PNJ]

Done both to the point I'm frightened of snapping the plastic bit that is being screwed into. I have a 14-16" long spanner to tighten it with so it's not like I'm not doing it tight enough.

[CharlesElliott]

Leak from somewhere else apart from the mating face?

[OutInTheShed]

Check the fittings.
If the washer is doing its job and sealing between the mating faces, there may be another route for the water, like a small crack in the metal, bad soldering of fitting to pipe etc?

[megaphone]

Try some flat washers, without the dimples, or some fibre washers. Make sure both matting surfaces are flat, no corrosion etc.

[S6PNJ]

CharlesElliott said:

Leak from somewhere else apart from the mating face?

Nowhere else for it to leak from

OutInTheShed said:

Check the fittings.
If the washer is doing its job and sealing between the mating faces, there may be another route for the water, like a small crack in the metal, bad soldering of fitting to pipe etc?

I'm sure that's the problem - getting the washer to do its job. As you say, a possible crack in the metal, though it wasn't leaking before I removed the fitting about 3 or 4 weeks ago to do some decorating around where it sits. The metal connection is a premade pipe, part of the water softener connection kit (22m full flow), so it's not a leak from the fitting to pipe (that's not where the weep comes from).

The weep seems to be coming from the rear of the nut and the water flow direction is plastic to metal (its the exit pipe from the softener), so the rubber seal seems to be sealing against the black plastic but not against the metal face, or it is somehow seeping around that face.

[OutInTheShed]

The better hose fittings have an inner raised bit which retains the washer in the correct place.
Possibly the washer is being displaced as you tighten the fitting.
Or possibly it's getting trapped in the threads and the pressure is not actually being applied to the washer between the mating faces.

A washer with a different OD might work, big enough OD to locate it, small enough to stay out of the threads.

As with any gasket that's at risk of being displaced, you could consider gluing the gasket to one face using your sealant of choice, and greasing the other face.

A fibre washer might have more resistance to getting trapped and distorted if that's the problem.

Possibly you are over tightening and forcing the washer out of the joint face?

There are hose fittings which 'just work', because they are well designed.
It's not clear from the pictures, I'm not sure both sides are actually intended to be sealed by a rubber washer.
If you look at a garden tap or a WM tap, the joint face tends to have a fairly thin rim so it applies pressure to a narrow ring of the rubber washer.

How simple things work is sometimes subtle.
Likewise how they don't work!

[Sheepshanks]

DIYer here: I use Fernox LSX on the mating faces (and both sides of the washer) of similar fittings - trick is to use enough, but not so much as it oozes out and interferes with the flow, and don’t do it up madly tight.

Edited by Sheepshanks on Sunday 11th May 13:49

[Road2Ruin]

The top photo, the surface looks like it needs a good clean. PTFE round the thread, too?

[Belle427]

Its not really needed but id try as above if all else fails and dress both mating surfaces with a sealant of your choice, let it set overnight before testing.

[johnoz]

What softener do you have ?

S6PNJ said:

I'm sure that's the problem - getting the washer to do its job. As you say, a possible crack in the metal, though it wasn't leaking before I removed the fitting about 3 or 4 weeks ago to do some decorating around where it sits. The metal connection is a premade pipe, part of the water softener connection kit (22m full flow), so it's not a leak from the fitting to pipe (that's not where the weep comes from).

The weep seems to be coming from the rear of the nut and the water flow direction is plastic to metal (its the exit pipe from the softener), so the rubber seal seems to be sealing against the black plastic but not against the metal face, or it is somehow seeping around that face.

[S6PNJ]

Hi John, it's a Monarch Midi with the 22mm full flow kit. I'm still having issues getting it to seal - off to Screwfix tomorrow for a different batch of 3/4" washers (pimply ones were from Wickes).

[johnoz]

S6PNJ said:

Hi John, it's a Monarch Midi with the 22mm full flow kit. I'm still having issues getting it to seal - off to Screwfix tomorrow for a different batch of 3/4" washers (pimply ones were from Wickes).

Hmm, had a sneaky suspicion it was a Harvey, but its not.

I would say change the hoses, if they have neen used for a while then removed sometimes this happens seen it before, don't know to why but they just do.

If its only one end on one of them, try swapping them over.

I yake it it the softener end thets the problem and not the bypass set? if you have the all in one plastic one.

[S6PNJ]

johnoz said:

S6PNJ said:

Hi John, it's a Monarch Midi with the 22mm full flow kit. I'm still having issues getting it to seal - off to Screwfix tomorrow for a different batch of 3/4" washers (pimply ones were from Wickes).

Hmm, had a sneaky suspicion it was a Harvey, but its not.

I would say change the hoses, if they have neen used for a while then removed sometimes this happens seen it before, don't know to why but they just do.

If its only one end on one of them, try swapping them over.

I yake it it the softener end thets the problem and not the bypass set? if you have the all in one plastic one.

It's not the bypass, it where the pipe leaves the softener. At the top of the unit, there are 2 90 degree turns (one in one out) where the water enters and leaves the softener. These platic pipes then fit into the 22mm full flow metal braided hoses and it's the plastic to metal joint that I'm having issues with. I'll take some more pikkies tomorrow. I'm loathe to disturb the one that is sealed in case I end up with 2 not sealing. Within teh plastic 90 deg bend, there are 2 other rubber seals (both much larger diameter) and they've also been loosened and tightened umpteen times as I try to solve the issue - they don't leak, just the one I'm having issues with.

When I apply water pressure (up to 3 bar - I have a pressure limiter in line), I start to see air bubbling out (before the water flows through the system) and it is coming from the metal pipe / nut flange, so the water (or initially air) is getting past the rubber washer somewhere, I just don't know where / how!

[johnoz]

It sounds like the matle end on the hose is not playing ball.

its either got a crack in it or one is forming, best try another host ti eliminate, as your washers are not working.

S6PNJ said:

It's not the bypass, it where the pipe leaves the softener. At the top of the unit, there are 2 90 degree turns (one in one out) where the water enters and leaves the softener. These platic pipes then fit into the 22mm full flow metal braided hoses and it's the plastic to metal joint that I'm having issues with. I'll take some more pikkies tomorrow. I'm loathe to disturb the one that is sealed in case I end up with 2 not sealing. Within teh plastic 90 deg bend, there are 2 other rubber seals (both much larger diameter) and they've also been loosened and tightened umpteen times as I try to solve the issue - they don't leak, just the one I'm having issues with.

When I apply water pressure (up to 3 bar - I have a pressure limiter in line), I start to see air bubbling out (before the water flows through the system) and it is coming from the metal pipe / nut flange, so the water (or initially air) is getting past the rubber washer somewhere, I just don't know where / how!