Slow draining toilet

Discussion in 'Plumbers' Talk' started by mcampster, Sep 21, 2016.

  1. mcampster

    mcampster Member

    The problem is that when I flush the toilet, it fills up the pan then slowly drains away (total time 10 seconds). There never seems to be enough 'suction' to do a good job. 9 times in 10, it does get rid of the waste, but often leaves the water a little murky or some tissue still in the pan.

    The waste pipe goes on a long run of approximately 10 meter at 2.5 degrees decline before reaching a junction where both this run and the main soil stack meet the main soil pipe running under the house. The main soil stack is vented, but no vent on this 10 meter run with the toilet at one end. A utility sink and washing machine discharge straight into the 10 meter run about 2 meters along from the toilet.

    To complicate matters further, due to the position of various steels in the house, the soil pipe is approx 40mm above the pan outlet. So it is connected with a 40mm offset, going UP, before continuing on the 10 meter run at 2.5 degree decline.

    http://www.screwfix.com/p/mcalpine-mac-4a-40mm-offset-pan-connector-white-110mm/34897

    I was under the impression whilst this was less than ideal due to water permanently sitting on the pan connector, it would not effect the discharge as the power of the flush would be enough to push up the extra 40mm, which is just a continuation of the upward rise of the trap in the pan. Is this impression wrong? Is this the main problem?

    I actually created a make shift air admittance valve by disconnecting the sink, which joins the 10 meter run approx 2m down from the toilet, and leaving the 32mm pipe open so air could enter the run. The result was not effected.

    Anything else I can try, or is it simply I cannot do the 40mm offset upwards? Would using a flexipipe make this better or worse?
     
  2. KIAB

    KIAB Super Member

    A flexipipe will make things worse.
     
  3. mcampster

    mcampster Member

    This was my assumption - since better to get the waste up the 40mm whilst the flush is at its most powerful.
     
  4. mcampster

    mcampster Member

    Will the main soil stack's vent be enough, or do I need to vent this run separately? The washing machine and utility sink seem to drain just fine, and not noticing a difference on the flush I'm wondering why I do not see at least some improvement.
     
  5. philthespark

    philthespark Active Member

    I normally work on a fall of 1 inch in 48 inches on a soil pipe,once it starts moving it usually flies along.
     
  6. KIAB

    KIAB Super Member

    Too shallow or too steep a fall,solids stay in the pipe, & water runs away, & the 40mm isn't helping the situation.
     
  7. mcampster

    mcampster Member

    Which is approximately 1.2 degrees. My 2.5 degree slope amounts to 1 inch in 33 inches, so should be fine.
     
  8. Pollowick

    Pollowick Screwfix Select

    Has it always been like it or was it fine to start? Possibility of a build up at the high point.
     
  9. Hi Camp.

    When was the loo installed like this, and was it always the case that it's slow to drain.

    I'm not sure what the 40mm upward slope will do to the drain-off speed, but suspect - like you - that once it starts to flow (ie when the pan water level reaches high enough to drain out the U-bend, which in this case would be 40mm higher than ideal - it would actually flow rapidly as you'd expect.

    I mean, a 10 metre run at 2.5o slope should have things moving along rapidly, I'd have thought.

    You added a make-shift vent to allow air in around where the pan is, and this didn't help, so we can probably discount it being a 'vacuum' issue.

    Mind you, if it were a 'vacuum' issue, then you could expect the sink and washing machine traps to gurgle quite alarmingly...

    It takes the pan 10 seconds to drain back to 'normal' (ie 40mm higher than normal) level after he cistern has finished emptying its contents into it? That's quite a while.

    It really does sound like a partial blockage.

    First Q again - Has it always been like this - from the day it was installed?
     
  10. KIAB

    KIAB Super Member

    One good way to clear a partial blockage is a large amount of water down the bog, I have used a dustbin half full of water more than once to clear a pipe.
     
  11. mcampster

    mcampster Member

    The whole bathroom was installed 3 years ago, and has always been slow to drain. I thought it was the toilet itself as it was cheap from B&Q - flimsy seat, flimsy flush handle etc. So I thought replacing it would solve the problem. So in the last 14 days I have replaced it with a new one. It was previously connected with flexi connector so the difference in height was not as noticeable. After much research from these forums and other place, I replaced the flexi with a 110 92.5 bend, a 110mm pan extender and a pan 40mm offset. I was actually really pleased with the job as it was my first toilet replacement :). No leaks!

    The only place there could be a blockage is the existing 110mm pipe.
     
  12. mcampster

    mcampster Member

    Do you get pans that have higher than normal outlets? 220mm is what I would need, not the usual 180mm as the current one is.
     
  13. Hmmm, ok.

    I honestly don't know what effect the extra 40mm height could have. It certainly isn't ideal, and it might possibly be the 'issue' here.

    I guess - soz - the best way to check is by removing the pan and cistern, making a temporary 40mm shelf for the pan, and chucking a bucket of water down it. You could even sit the cistern on top and fill it up using a buckets (no need to plumb it in) and then flushing it - that will give a more accurate test.
     
  14. Can't say I've seen an actual example, yet tho'... :(
     
  15. Pollowick

    Pollowick Screwfix Select

    DAs cooment about raising it short term to prove whether it is te 40mm or a blockage is a first step. It does sound as though the 40mm is the issue.

    Not cheap and will need some work. Get a complete new WC - a FRAME HUNG one, with a frame from someone like Grohe. Install 40mm above "normal" - the frames have adjustment up and down, then box in fame and fit WC - the cistern is within the boxing and attached to the frame. I have just measured the height of mine compared to a standard pan and it is about 45 mm above.
     
  16. Pollowick

    Pollowick Screwfix Select

  17. mcampster

    mcampster Member

    That's a nice suggestion. I've actually just fitted this whole unit which I got ex-display, so I will have to look into whether or not a I can get a frame to sit inside the cabinet. But before I do this, I guess I will have to do this test first.

    http://upload2.evocdn.co.uk/tavistock/uploads/prod_img/2_1403_e.jpg
     
  18. mcampster

    mcampster Member

    Me neither :-( I really appreciate all the ideas ... I've asked questions on other forums before and the members are often less than helpful. So thank you everyone.
     
    Pollowick likes this.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice