Poorly flushing wc

[k-e-e-f]

First post:

As the title says we have an Armitage Shanks Wentworth wc which has never worked properly
since it was fitted. I have tried cleaning the holes under the rim, The flush seems to go down ok
if you look in the cistern i.e. the whole tank goes down. It's just that it doesn't clear the pan.
Could this be a fault somewhere in the casting? I am thinking of changing the siphon to a more powerful
version- would this provide a solution? Can't believe how bad this is.
Any advice appreciated.

(The wc is completely standard single flush with a lever.)

 

[oldbuffer]

There should be a line marked in the ceramic of the back of the inside of the cistern. If the water is not filling up to this mark, then less than the standard 6 litres will be flushed, which could be your problem.

Adjust the height of the float valve so that the cistern does fill to this line.

 

[k-e-e-f]

hi, The cistern is filled to the top of the overflow pipe.
I don't think this is the problem but thanks for your reply.

 

[Scally-Ho]

How old is the china? Need to know so that to establish if fitted with a syphon or a flushing(dump) valve, or a series number could be helpful.

 

[k-e-e-f]

Its 40 years old.
Where do `i find a serial number?

 

[Scally-Ho]

I said series number NOT serial number.
At 40yrs of age, the flushing mechanism will be a syphon unless the innards have been renewed within the past few years. This means that there is a possibility of the syphon's diaphragm becoming distorted or not flexible enough to allow a good passage of water. Take the syphon out and renew that diaphragm; that might improve the flush speed. It might even be a damaged syphon allowing air ingress.

Toolstation

www.toolstation.com

 

[k-e-e-f]

Thanks, Do I have to detach the cistern from the pan to get at the siphon?
I think there is a series number under the lid - 1765

 

[Scally-Ho]

The syphon cannot be removed without separating the cistern from the pan.

 

[k-e-e-f]

That's what I thought.

 

[CountryFan]

Thanks, Do I have to detach the cistern from the pan to get at the siphon?
I think there is a series number under the lid - 1765

From that it sounds like you have a Close coupled cistern, so yes would need to be removed and likely a new donut washer and possible plate too. Something could have got into the cistern and blocked the holes. Perhaps the syphon is an adjustable type and the air hole has changed?

 

[k-e-e-f]

Yes i think I will have to dismantle it and take a look.
What is a good brand of syphon to replace with?

 

[CountryFan]

What is a good brand of syphon to replace with?

Thomas Dudley are good and expensive. Wirquin/Celmac are ok too. Fluidmaster are good. So a few to choose from, but probably best getting one you can service (dismantle)

 

[Scally-Ho]

Your replacement syphon will depend on the height of the waterline marked inside your cistern.

 

[k-e-e-f]

Ok thanks for the info.

 

[foxhole]

There is a huge variety of toilet designs , many have poor design and flush is less than perfect .
Only real solution if everything works as it should is to replace pan .
Older toilet were often used with high level cisterns which often negated the poor design due to the power of the flush.