Toilet drains slowly

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Hi Team

I'm hoping someone can help me understand and fix a slow draining close couple toilet on the ground floor.

It started a week ago. I did all the usual plunging, asked the kids if they put something in and then hot water and detergent. The water was always clear in the bowl but slow to drain. on occasion is made a gurgling noise.

I've now taken the toilet off to have a look at the 4inch drain pipe. Its in clean condition with approximately 50cm of dry/empty pipe before I see water at the bottom.

I then poured a number of 16litres cold water buckets straight into the pipe and the water flowed freely away. It did not accumulate in the pipe at all. I put the hose down there to give it a good flush and again no slow draining. I then replaced the existing WC connections for alike. I put a short straight extension piece directly in the drain pipe to give me more height approx. 15 cm. I then fitted a replace McAlpine space saving bend WC-CONQ. I then reconnected the toilet bowl only and poured a number of 16 litre cold water buckets in the pan. Again its slow to drain.

I took the pan off the wall and remove the rubber fins from the bottom of the 90degree space saving bend WC-CONQ just so i could get it off and on easier whilst I tried to resolve. With the rubber fins off I can pour 20 litres straight into the bowl and it flows fast away. As soon as I put the rubber fins/gasket back on to make it water tight the water drains slowly. I'm assuming its something to do with a vacuum and lack of air

I'm now scratching me head on what to do next. The upstairs toilet works perfectly. I was on the roof in the past 3 weeks and purposely checked the stack and it was clear i.e. no birds nests.

I can send photos if it helps. Appreciate any guidance. FYI I move in to this house in Feb and the toilet worked fine up until a week ago. All the other sinks, outside hoppers are free flowing.

Thanks

Rob
 
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Hi Andy

firstly thanks for the reply.

Unfortunately I cant check the manhole. It has been covered up (tiled over) approx. 20 years ago. I have an indemnity policy against this if I need to lift in an emergency. My plan is to restore access when I renovate the kitchen.

The manhole is approx 50cm from where the downstairs problem toilet is. My thought process was, as I've seen the toilet drain pipe clear quickly I have assumed the manhole it connects to will be free. This manhole also connects to the two hoppers outside the kitchen which are also free flowing.

I've just been on the roof again and put a hose down the main vent pipe. There were no signs of blockages or nesting.

This downstairs WC is an extension it connects to a manhole under the kitchen and then joins the main sewer line where the vent stack it. I cant confirm exactly how its vented. I'm just puzzled becasue its works for the past 8 months. Its not a new bathroom either. at least 5 years old. Something must have changed locally but I cant put my finger on it.
 
Are you sure something was not stuck in the toilet?

You could take the toilet out again and call someone round and have a drain camera put down the drain line.

Andy
 
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A second question

Would adding a McAlpine WC-CON8V and air admittance valve to be compliant or advisable? I assuming this would resolve any vent issue.
Low%20Price_3

ae235


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FLOPLAST AF32W AIR ADMITTANCE VALVE
 
Is there a basin in the room? if so, disconnect the pipe from the trap and see if the toilet flushes correctly.

Andy
 
Hi Andy

Thats a great tip but sadly the sink and shower drain on an alternate route to an outside hopper. This hopper then comes back into the home and connect to where the slow flushing toilet connects in the manhole. The sink and shower outlets in the hopper are not under water and are free to air. I guess the extensions on this house haven't had the plumbing completed as would be expected by todays standards. I'm fairly certain the toilet pipe is blocked but will consider the camera idea. With Covid I'm paranoid at having someone in at the moment because I'm under the venerable list and working from home.
 
You've got a blockage in the system somewhere, which is preventing the discharge from the WC draining away. Result, there is a plug of air in the pipe between the blockage an WC, so when you flush the WC, the discharge from the pan has to try and displace the equivalent amount of air, it cant very easily so the water backs up and slowly subsides as it finds its own level. The AAV will not help in this instance, as it only allows air into the system, you have a problem with trapped air that cannot find its way out. However, once the drain is cleared, this problem will not arise anyway.

Removing the pan, or breaking the seal on the pan connector effectively vents the pipework from the top end, (hence Andy asking if you had a basin in the room, removing the trap could allow the pipework to vent from there assuming they were directly connected), and allows the water to immediately displace the trapped air in the pipe and thus find its own level.

You may not have an option but to uncover the manhole I'm afraid, chambers are fitted for a reason and covering them up is never a good idea. It may be possible to try and jet or get a suitable cleaning tool down the pipe from inside after the pan is removed again, and unblock the pipework, but then if there is an underlying issue with the drain that cannot be seen from upstream, you may find yourself back to the start again before too long. This is also quite a messy procedure and is far better done from externally whenever possible.
 
Hi Hugh

Thanks for all that info. Really useful to hear from someone who clearly understand the plumbing world (not me). I have taken it on board. I really appreciate both you and Andy taking the time to offer your thoughts. I can accept that this is probably a system problem rather than something easy. I work in engineering and like to get things done properly. I traced out the manhole a few moment ago thinking this is my project for tomorrow. My wife and I were discussing why now, when an elderly couple have lived until recently and have been here since 1987. I guess the toilet has now had a flogging with a young family moving in (girls and toilet paper) and lock down ( more time at home)

I'll be looking at my indemnity policy tomorrow. thanks
 
Women and toilets are often not a good combination, a gentle remainder of what can/cant go down may be needed. Also possible the previous occupants put a few things down they shouldn't have done, and now with the extra load, the system is creaking. I would strongly recommend you open up the manhole and get a proper assessment of what is/has gone down there, possible build up of FOG (fat/oils/grease), wipes etc, which, once removed, (provided similar are not put back down the system), will give you many more years of trouble free operation.

Good reminder here that Anglian Water are currently using.
Straight Flush.jpg
 
Don't use the above item if you have a flexible pan connector. But you can it you remove the toilet again.

Andy
 
Guys

You've been absolutely great. Since the pan is off and I have a clean pipe approx 50cm away from the covered drain I'll give it a go. I've just found the plans from the original extension and thought id share the drainage plan FYI. I'll take the pan off and rod down to the covered drain
 

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If everything else is draining away ok then the blockage could just be in the run from the toilet to the manhole. Don't be surprised if you have a blocked manhole which might need to be jetted.

Andy
 
Thanks Andy.

Do you think a professional with a Jetta can get down a vertical 4 inch pipe, approx. 70cm and feed to the covered drain approx. 50cm away? I've no experience how flexible the equipment is. I love DIY and engineering but this little problem is beyond the keen DIY man
 

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