Saniflo water goes back in and repumps to loud banging in pipes

[Southgate]

Hello,

I have had a Saniflo PRO XR for three years. Still under warranty and I put cleaner/descaler every three months. It is used once or twice a day. The first year there were no problems.

Then it suddenly started to go off intermittently during the night. I took out the Elbow where the non return valve was and replaced with a new one. Then three months later, the same thing started to happen. But this time it was as if the pipe work from inside the wall was about to come off. It would flush OK. So this time I took it out and cleaned just the plastic non returned the valve and it would be fine for the next two months. I seem to have to do this every two to three months. It is not consistent. Only once have I actually found anything inside the non return valve that could have stopped it from shutting properly.

Issues:

1. When working fine, a small flush or running the tap, where the motor runs for a shorter time results in a shudder and bang from around the non return valve once the motor has stopped. Whereas a long flush doesn't result in this. The days before, what I believe to be siphoning i.e. the constant noise of water from the vertical waste pipe going back into the machine and you can feel and see pumping of water going from the plastic piping attached to the elbow and going back into the saniflo.. It then starts an uncontrollable cycle whereby the saniflo fills and pumps then in 30 seconds the water comes back in from the waste pipe and then the motor runs, plus lots of banging as the water goes through the non return valve into the machine.
2. Aside from that problem I notice that there is double the sound level of the motor when flushing the toilet on some days.
3. I have had to on about 3 occasions during the last three years notice smell and some urine coming back into the pan over night. When this occurs I turn off the machine, flush once and very lightly use a plunger. Then faeces/urine come into the bowl and then I flush it and then no more smell or unrine coming back in.

I have attached some pictures.

Is this bad pipe work? Is it siphoning and a simple air valve at the top of the Vertical wastepipe a solution?

Sorry for taking up your time and interested if you know what is going on with the three issues.

 

[rpm]

Change the non return valve and clip discharge pipe to a wall.

 

[Southgate]

Thank you so much for coming back.

In my ignorance can you give a bit more detail of what you mean by "clip discharge pipe to a wall". Are you referring to be that goes into the wall or actually within the wall?

 

[rpm]

Sorry, I meant the vertical pipe if it isnt already clipped to a wall to stop it moving around, however not so easy to do if it is fitted within the wall.

 

[Southgate]

Thank you once a gain for the reply. I have determined that it is still clipped in the wall. If it was a continuous problem I guess it would be easier to diagnose, but it only happens ever couple of months. The banging noise emanates from the water going back through the non return valve , which comes at such force that the pipe work shakes. The non return valve has been changed over 3 times in the last year and a half. One person mentioned that it is syphoning back into the saniflo and so maybe at the highest point of the waste pipe on the 1st floor to put some kind of valve (not sure of the exact name).

 

[rpm]

Certainly sounds like the non-return valve isnt holding water back in the pipe. Is the outlet pipe within or very close to the maximum lift allowed for that model?
It is not syphoning

 

[Southgate]

The waste pipe goes up vertically three metres and then runs for six metres horizontally till it meets the outside Wastepipe from the main bathroom. I have looked at the specs and it is well within the limits. Is that what you are asking?

As you mention it is not syphoning, are you suggesting that somehow the pipework is making the non-return valve ineffective. It is the third one so they can't all be faulty.

 

[rpm]

The waste pipe goes up vertically three metres and then runs for six metres horizontally till it meets the outside Wastepipe from the main bathroom. I have looked at the specs and it is well within the limits. Is that what you are asking?

As you mention it is not syphoning, are you suggesting that somehow the pipework is making the non-return valve ineffective. It is the third one so they can't all be faulty.

Well, as long as the six metres horizontal has the minimum slope on it and there isnt any dips or a second rise in its lenght then from here I am baffled and yes I would agree not all non return valves can be faulty unless you have very, very hard water.

 

[Southgate]

Well, as long as the six metres horizontal has the minimum slope on it and there isnt any dips or a second rise in its lenght then from here I am baffled and yes I would agree not all non return valves can be faulty unless you have very, very hard water.

I am in north london and the water is hard, but it doesn't cause major issues on other plumbing.

OK, so really the only way is to lift up the floor boards and to see that the minimum slope is there, no dips and that the clip hasn't come off in the wall. Maybe the first time it happened it caused something to shift. The first year and a bit there was no problem at all. I would have thought it would have started to happen very early on if the pipe work wasn't set up properly?

What you are implying is if the pipework is not correct and the correct pressure is not exerted on the non return valve then it might not seal correctly and hence the water goes back into the saniflo?

 

[Lou]

(Just bumping a few older threads, they will drop off what is new soon)

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