HELP! Non-return valve 1 1/2” ?

[Mottie]

We've juuust averted a Christmas Eve disaster. We have no open drains in the houses down our street - the cast iron soil stacks at the rear of the houses just disappear into the ground and join the sewer/pipe that runs along the back of our houses. All semi-detached houses with about every 4th or 5th shared drive having a manhole. Our street runs downhill and we live about a third of the way down the bottom. In the 32 years we've been here we've had 4 or 5 occasions where the drain has blocked somewhere downhill resulting in the sewage backing up and gurgling up our sink! You can imagine what comes up. Tonight, I heard a worrying gurgle from the sink and sure enough, water started coming up through both sink plug holes. We have no overflow on our kitchen sink so literally just as the water level reached the top and started to overflow I bunged both plugs in and held them down. (It’s never got to the top before, always settled approx halfway up the sink). The water was warm and I found out that next door which is higher up had just emptied their bath. I held them down for about 5 minutes and when I carefully removed one plug, the water went down immediately so I took the other plug out and both sinks drained immediately. I assume the sheer weight of water forced the blockage clear? We have one 1 1/2” pipe going to the soil stack outside and that takes the waste from the sink with a connection taking the dishwasher and washing machine but neither of those had water flowing into them - I assume that they have non-return valves. Does that sound right? Edit: looking at the pictures, would you say they are non-return valves?





We also have a macerator in the downstairs loo but I’m pretty sure that has a built-in non return valve in the waste pipe.

What I’d like to do is fit a one way/non-return valve between the sink and the soil stack - either inside or outside so that if it ever backs up, waste water will not backflow into the house. Will this work and can you recommend a good quality unit? Thanks

 

[Deleted member 267285]

HepVo valves may work, but water will usually leak at its weakest point under pressure, so it’s likely fitting these would result in that if it happened again.

 

[Mottie]

Just looking online, would one of these work?

Multifit In-Line Non-Return Valve | McAlpine Plumbing

Achieve efficient water flow with the Multifit In line Non Return Valve, ensuring prevention of backflow for a reliable solution.

mcalpineplumbing.com

HepVo valves may work, but water will usually leak at its weakest point under pressure, so it’s likely fitting these would result in that if it happened again.

If I fitted it outside, on the run to the soil stack, I wouldn’t give a flying one if it leaked - at least it would be leaking outside the house!

 

[Harry Bloomfield]

Just looking online, would one of these work?

If your external pipe is horizontal, worth a punt.

I cannot see any obvious none-return valves on your appliances, but the above should protect them all. Possibly the back flow, was just a result of several discharging water at the same time?

 

[Mottie]

I cannot see any obvious none-return valves on your appliances, but the above should protect them all. Possibly the back flow, was just a result of several discharging water at the same time?

Looking at the dishwasher connection in the top picture, there is an arrow on it so I’m assuming that it must be fitted in the direction of flow so possibly a one-way valve?

If it was just a result if several discharging water at the same time, I think it would happen more frequently that 4 times in 32 years! It came up higher than my worktop. Before now, we have had to have drain people out to Rod the drains out. Other times it has taken several hours to clear itself.

 

[Deleted member 267285]

Just looking online, would one of these work?

Multifit In-Line Non-Return Valve | McAlpine Plumbing

Achieve efficient water flow with the Multifit In line Non Return Valve, ensuring prevention of backflow for a reliable solution.

mcalpineplumbing.com

If I fitted it outside, on the run to the soil stack, I wouldn’t give a flying one if it leaked - at least it would be leaking outside the house!

I don’t see why it wouldn’t work.

 

[just pumps]

Just looking online, would one of these work?

Multifit In-Line Non-Return Valve | McAlpine Plumbing

Achieve efficient water flow with the Multifit In line Non Return Valve, ensuring prevention of backflow for a reliable solution.

mcalpineplumbing.com

If I fitted it outside, on the run to the soil stack, I wouldn’t give a flying one if it leaked - at least it would be leaking outside the house!

Yes it will work but must be fitted on a horizontal run.
And the right way round!!!

 

[Mottie]

Yes it will work but must be fitted on a horizontal run.

That’s good because I have two of those - one inside and one outside. Might have to fit it inside though as the outside one is only about 6” long with glued ends and fixed where it comes out of the wall via a 90° bend and the soil stack with no wiggle room to get it in.

 

[Hugh Jaleak]

I'd be careful trying to cut into the external section in your picture, it's all solvent welded, and looks rather weather worn, may shatter once you try and cut it. Although it does appear you have a plastic stack going into a 'Timesaver' type joint onto the cast, so be prepared to replace a section of the 110mm if the worst happens.

 

[Mottie]

Update: I’ve decided against it! 1, because of the aggro that I might encounter fitting it in the only horizontal run I have. 2, because my drainage problem will be resolved when they replace/repair the drain that keeps blocking but mainly, 3, because of the instructions that come with the thing that state 'Should only be used if there is no alternative' and 'Required to be cleaned regularly'. The cleaning regularly bit turned me right off - I’m looking for a fit and forget solution!

 

[Mottie]

Update 2: I didn’t have the length outside to fit an inline non return valve and as already said, I didn’t want something that needed maintaining. Thames Water, despite saying that the drains need replacing are still dragging their heels and the 39m of drains that need replacing are going to cost (according to the network engineer) around the £50k mark so it has to go to a 'budget planning meeting'. Apparently it was put on hold at the January meeting as they had worse cases to deal with so us going to the February meeting. I’m not holding out much hope for that either, especially as it hasn’t overflowed since Christmas.

I was talking to my mate about it and he said he'd fitted a non-return valve to his shower waste to stop smells coming up but it didn’t work - the water wouldn’t flow away. Looking on the instructions, he then saw that it wasn’t suitable for showers so he took it off. He gave it to me - THIS ONE.

I've just fitted it to the pipe going from my sink waste to the soil stack. Water from the sink and washing machine flows away fine. At least I have something there that should hold back the flow of sewage should the drain block again. Fingers crossed!

 

[just pumps]

Sorry but you would of been better of fitting the first one imho.

 

[Mottie]

Sorry but you would have been better off fitting the first one imho.

Apart from regular maintenance, the first one had to be fitted on a horizontal pipe and the only horizontal pipe was too short to fit it in. Hopefully this is only a temporary solution until the drains are fixed properly.