Toilet seems to have a weak flush

sand_hun

I noticed that one of the Heritage toilets in my home appears to have a weak flush. Specifically, it won't easily flush away toilet tissue. I think this has become more of an issue in the last 6 months or so.

I took the lid off and looked in the cistern. The water level is approx half an inch below the white (overlow?) pipe on the left.

Can anyone advise what I can try in order to resolve this issue before I contact a plumber. Thanks.

Niv

If its been the same set up and nothing has changed in that time then my guess is its the diaphragm that's gone. You can get replacement ones, but I wouldn't bother, I would just replace the unit .
Something like this:
https://www.screwfix.com/p/flomasta-dual-flush-siphon-95mm/179FY?tc=YT4&ds_kid=92700055281954514&ds_rl=1249404&gclid=EAIaIQobChMIwoPgiLm87wIVCKp3Ch1opwY4EAQYAyABEgJTQPD_BwE&gclsrc=aw.ds 

sand_hun

@Niv, By replace the unit, do you mean buy a new toilet rather than a new diaphragm?

Niv

sand_hun said:

@Niv, By replace the unit, do you mean buy a new toilet rather than a new diaphragm?

Replacement of the bit i linked. Its about £6. Takes longer to drain the water then replace the part.

nofoollikeold

1. A syphon is a device which either works or it doesn't.  If the diaphragm has failed, it won't flush at all, or it will take several pushes of the handle but then will fully flush.  So I don't think its the diaphragm.
2. Changing the diaphragm, or the whole syphon mechanism, means taking the cistern off the WC pan, as it is a close coupled unit.  If you end up doing so you will need:
2a. A new syphon.  Use a Dudley Turbo 88 as then in future you can change the diaphragm without dismantling the WC.
2b. A new close coupling kit, such as Screwfix 84958. 
2c. The above kit includes a "doughnut" washer, however it is possible yours is different, in which case you will need to get a new one from a decent plumber's merchants.
3. If this is an issue which has occurred gradually, then, if you don't need multiple attempts to flush, I would check:
3a. That the water level in the full cistern is at least up to the line on the back of the cistern marking the expected water level.  You could afford to allow it to go a little above this line provided it is below the overflow level.
3b. That the flush is even across the pan.  The channels under the rim can get blocked / lime scaled, reducing the vigour of the incoming water.  If that proves to be the issue, clean / de-scale under the rim.

FreeBear

If it is a close coupled cistern, then the rubber washer at the join may need to be replaced - The usual recommendation is to replace when ever the cistern/pan is disturbed..

https://www.screwfix.com/p/viva-pp0030-1-close-coupling-kit-silver-black-180mm/924ht

Apodemus

An alternative line of thought...  You've not changed the type of paper you use have you?  Some types are much more resistant to wetting, and hence flushing, than others.  I'd hate to have you dismantle your toilet just to find that a change of paper would have achieved the same thing! 

shinytop

Apodemus said:

An alternative line of thought...  You've not changed the type of paper you use have you?  Some types are much more resistant to wetting, and hence flushing, than others.  I'd hate to have you dismantle your toilet just to find that a change of paper would have achieved the same thing! 

Another thought along the same lines based on experience.  Does the cistern empy in the normal way when you flush?  If so it's possible the drain could be partially blocked. This coud make paper or certain, emm, larger objects more reluctant to flush without actually backing up.  We have a toilet that's very sensitive to this.  It's easy to fix but involves plungers, rods and rubber gloves.  May be more likely on a ground floor, where gravity has less of an effect.  

sand_hun

Toilet paper does flush, but it will sometimes take 2 or 3 goes. We may have switched to bulk packs from Amazon, but it seems fine in other toilets in the home.

@s@shinytop I'm pretty hopeless at this kind of thing so can't be 100% certain what the normal behaviour of a cistern is.  I'm pretty sure that, upon flushing, the water level in the cistern temporarily reduces as the bowl fills up. Then the water level in the cistern fills back up.

Jeepers_Creepers

sand_hun said:

@s@shinytop I'm pretty hopeless at this kind of thing so can't be 100% certain what the normal behaviour of a cistern is.  I'm pretty sure that, upon flushing, the water level in the cistern temporarily reduces as the bowl fills up. Then the water level in the cistern fills back up.

Ooh, that's interesting. When you flush a syphon toilet like yours, the cistern should really empty pretty much fully, leaving just around a half-inch of water in there, and then it refills.

See the photo you posted? The link from your lever goes into a black plastic body, which is kind of oval-shaped (a squashed oval) at the bottom. Yes? The bottom of this is where the water is drawn upwards, around the blue-topped pipe, and then straight down a central black pipe and into the pan. Ok, that 'oval' part is sitting around an inch or so up from the cistern bottom - yes? You can slip your fingers under there? Ok, when you flush, the water level should drop to that point!

You seem to be saying that the water level 'temporarily reduces' before then refilling?

Can you confirm; allow it to fully fill, pull t'handle (does it operate easily with a normal pull?), and then watch the water level. It should plummet quite rapidly - I dunno, taking around 5 seconds-ish? - until it reaches the bottom of that 'oval', whereupon it might gurgle a bit as air is also drawn up there. Then the flush stops and the cistern refills.

What does yours actually do?

coffeehound

nofoollikeold said:

3b. That the flush is even across the pan.  The channels under the rim can get blocked / lime scaled, reducing the vigour of the incoming water.  If that proves to be the issue, clean / de-scale under the rim.

Given the foregoing, this looks likely, and can be tackled first without dismantling the loo.  

Using an L-shaped piece of clothes-hanger wire, or Allen key, go around the underside of the rim and poke through any limescale build-up in the holes.

This video at 4:20 shows the procedure

https://youtu.be/_15OKXl9NRQ?t=261