Leaking Hot Water Pipe Joint on Negative Head Hot Water Pump

54and56

Hi all,

With perfect timing the joint connecting my hot water negative head pressure pump decided to fail and is now pi$$ing water through the ceiling (leaking through the upstairs floor where the pump is located) whenever the hot tap is turned on and even when the pressure drops (due to slow leaking) when the taps are off but the pump kicks in to refill the pressure, see photo below.

I understand I need to get a replacement for the piece of pipe highlighted in red below from a pump supply shop which comes with the plastic fitting etc already attached.

I think I can source the part but my question to the experienced in the group here is whether this is a straightforward unscrew and replace type job I can do myself or do I need to get a plumber to do it? On a scale of 1-10 when it comes to plumbing DIY I'm about a 4!!

We can't have any hot water showers until this is fixed so there's a bit of urgency to getting it done.

The Continental Op

That really is a basic DIY job. The biggest difficulty is draining everything down (or if you are lucky shutting off a couple of valves) to replace the fitting.

The old plastic end of the fitting should come off if you push that end with a lip on it back into the body of the fitting. Then it should push off (push on the end lip with either a special tool for the job or an adjustable spanner set a bit bigger than the pipe.

On the pump unscrew the nut and remove any old washer if its not inside the fitting then make sure there is a new washer in the new fitting hand tighten then probably about half a turn with a spanner.

Turn water back on check for leaks job done.

Edit: You might want to hold the fitting below the nut with water pump pliers on the water pump to make sure you don't unscrew anything you don't need to. Basically a 2 tool job - good adjustable pliers and water pump pliers.

This is what the dismantling tool looks like https://www.amazon.co.uk/15mm-Speedfit-Release-Aid-15RA/dp/B0776FZZ52/ easy to replicate with a suitable sized spanner or adjustable spanner.

54and56

https://www.boards.ie/discussion/comment/120014883#Comment_120014883

Sounds like a level 5 job but I might give it a crack.

Appreciate the guidance, thank you.

54and56

https://www.boards.ie/discussion/comment/120014883#Comment_120014883

I think I'm lucky in that the red valve to the right controls the flow to (or from?) the pump?

I tried taping the component that's leaking but it made zero difference. I guess the pressure of the system finds the weakest point and unless it's 100% watertight it'll pour through once the pump kicks into action as that's exactly what's happening. Turn the hot tap on and it absolutely shoots water out of the cracked / compromised component.

Really hope these are a standard enough stock item for pump supply companies as I'm hoping to pick one up tomorrow morning.

Sleeper12

If in Dublin St Pumps & Domestic Pumps will have this part in stock.

It would be worth checking that the thermostat is functioning correctly on the immersion. One reason for the part to fail in such a way is because the water is too hot.

10-10-20

Definately buy locally, but just for reference here's similar online:

https://www.screwfix.com/c/heating-plumbing/push-fit-hoses/cat831682

The Continental Op

Just an obvious plumbing point for the OP.

Mark in permanent marker how far the current fitting is pushed on, then when you replace the fitting you can be 100% confident its on far enough.

FishOnABike

https://www.boards.ie/discussion/comment/120015471#Comment_120015471

The red valve seems to be on the cold water pipe behind the pipe that's connected to the pump.

Are the inputs to te pump on the left or right in that picture?

The push fit connectors look to have a flat head screwdriver slot in them. It's probably an in line valve. Turning it quarter turn should stop the flow through the valve. You'll still need to stop the flow from the pipe it's connected to while swapping out the flexible pipe.

54and56

Great info and advise from you guys, thanks very much. In the 20 (?) odd years I've been a Boards user it's rare I haven't been able to connect with genuine helpful and knowledgeable people when needed. It's what makes this site IMHO.

So I drove over to ST Pumps in Phibsboro and showed the (funny) guy at the counter the photo of my pump and piping etc. Without a word he reached under the counter and pulled out an identical flexi hose to mine and asked if mine was leaking from the joint in the middle of the plastic valve piece. I said that's exactly what's happening and he said if I don't want a repeat of the problem some years down the line I should use another all steel flexi hose and valve rather than replace like with like. I assumed being an ignorant consumer I was being upsold so I asked why the original wasn't the better option and he said the original parts that come with the pump contain instructions that they must be installed straight into the piping with no bend whatsoever but a lot of installers (mine included) can't be ar$ed doing the extra bit of pipework to comply so bend the hoses to fit the pipework and over time the vibrations find the weakspot in the valve and it cracks exactly as mine has.

The explanation seemed fair enough and is obviously something he goes through on a fairly regular basis so I said fair enough how much for the replacement hose you recommend and it turns out it's less than 50% the cost of the original at just €8 - https://st-pumps.ie/product/500mm-3-4-flexi-hose/

I bought 4 of them and now have to figure out if I have the cahoonas to replace all 4 myself so the other ticking time bombs are put to bed once and for all or do I get a plumber to do it? My instinct is to try and get a local plumber to do it but if I can't get any one by tomorrow afternoon I'll just do the one that's stopping the whole show myslef and then after Xmas get a plumber to fit the other 3 and double check mine in on and working OK.

The Continental Op

I assume you bought 4 isolation valves at the same time?

Something like this https://www.screwfix.ie/p/full-bore-isolating-valve-15mm/46860 x4? You can throw the olive and compression nut away from one end and attach the hose you linked to directly as conveniently they will be the same size, just don't forget the sealing washer inside the nut on each flexible hose connection.

Also when connecting to the qualpex make sure there is an insert inside the fitting.

tbh considering the small cost of one direct replacement I think I'd have gone like for like.

btw the isolation valves are there so you can swap out a failed pump without too much effort and the flexible hose helps reduce vibration (noise).

10-10-20

There's a good bunch on here in fairness. Good wide knowledge of subjects. It's not often do they get recognised. 👍️

If you have a wrench then you should be good to go, except what way does that larger joint fit onto the pipe - is it a compression fitting or can you take a photo? If it's compression then you'll need what's called an "insert" to strengthen the pipe. A photo of the inside of the wider end will tell us.

54and56

https://www.boards.ie/discussion/comment/120018429#Comment_120018429

My bad, I linked to the wrong product, shows you how little I really know!!

These are the replacement hoses I bought which have an isolation valve built in.

I was going to have a crack at replacing them myself but a friend referred me to a local plumber who said he'll try and get to me today or tomorrow so tempted as I am to have a go I think I'll leave it to the skilled professional as the last thing I want in the run up to Xmas is to somehow mess things up even more.

Cold showers or showering in the gym is the order of the day for the family. I'm not Mr Popular at the moment but C'est la vie!!

Kencollins

Did they give you inserts for the brown plastic pipe by any chance? You are replacing push on connectors with compression fit connectors on the brown qualpex pipes, so the inserts are a MUST. All you have to do is take off the old fittings, push the inserts into the brown pipe, and then tighten the connection on the new fitting to a tight but not obliterated tightness! No PTFE tape needed. These are the inserts:

https://www.goodwins.ie/products/Qualpex-Inserts-1-2-inch.html

The pump side connections have a rubber gasket, so they need dont need to be tightened as much.

Ken

54and56

https://www.boards.ie/discussion/comment/120020941#Comment_120020941

Thanks Ken, no I didn't get any Qualpex Inserts. Mmmm, might hop out to get some later before the plumber (hopefully) arrives. I guess he might have some but better safe than sorry.

Will Woodies or Chadwicks carry Qualpex Inserts? I'd hate to have to trapse all the way back over to Phibsboro for them!!

Edit: Woodies sell them - https://www.woodies.ie/push-fit-fittings-1-2-pack-of-plastic-inserts-335723

The Continental Op

https://www.boards.ie/discussion/comment/120022126#Comment_120022126

Always worth having a few but all joints to qualpex, push fit plastic, push fit brass and compression fittings should have inserts, so ideally they should already be fitted. Be very surprised if a plumber didn't have any on them.

54and56

https://www.boards.ie/discussion/comment/120022144#Comment_120022144

Of course as luck would have it the plumber arrived when I was bang in the middle of an important 2 hour Teams call I had to be on. Ducked out for 1 minute to show him the pump and told him I didn't have any Qualpex inserts but he said no problem.

Job now sorted and all is good with the world.

Thanks again to you all, very helpful and knowledgeable.

The Continental Op

Always good to get an update on the end result and even better when you get before and after pictures.

For reference do you mind saying how much the plumber charged?

54and56

https://www.boards.ie/discussion/comment/120022572#Comment_120022572

€80 but I gave him a tip on top as I know he was squeezing me in and I want him to want to come back if I need him again!!

I know I could have saved the cash and done it myself but I'm really not that competent a DIY'er 😥