Easy question - replacing a toilet syphon

[ey143]

If it is the large doughnut washer, then again it means the cistern needs to come of the wall right?

 

[Belboz]

If it is the large doughnut washer, then again it means the cistern needs to come of the wall right?

Yep.

The doughnut washer sits between the pan and the cistern. The flush valve exit pipe sits in the 'hole'. You may have disturbed the doughnut whilst removing part of the syphon.

If the leak is from there, whether the doughnut needs replacing or not, it will necessitate uncoupling the cistern from the pan.

In all honesty, if you have to uncouple then best to change the doughnut valve anyway. They are cheap as chips.

 

[ey143]

Will have to check.

Is there a t particular reason why they don't make the diaphram more solid or tougher? I'm trying not to be cynical and think its because they want you to replace the part. But I can't find a logical reason why this part cannot be made to last forever since all its doing is holding water. If as someone above pointed out, it is made of cut out plastic milk bottles, how is that likely to fail unlike a think plastic bag membrane type?

 

[Belboz]

Will have to check.

Is there a t particular reason why they don't make the diaphram more solid or tougher? I'm trying not to be cynical and think its because they want you to replace the part. But I can't find a logical reason why this part cannot be made to last forever since all its doing is holding water. If as someone above pointed out, it is made of cut out plastic milk bottles, how is that likely to fail unlike a think plastic bag membrane type?

I think that the very nature of the job it needs to do makes a more solid version unworkable. Hence why no-one has done so.

I assume they could use some form of longer lasting material but then (a) the unit would cost more and probably be less competitive and (b) they wouldn't get their spares money!!

Easiest solution (as suggested) is a flapper valve. Very little to go wrong and very very simple to fix if it does.

Just IMHO though.

B

 

[Elkato531]

The siphon diaphragm needs to be flexible as it has to let water through when the piston returns to the down unflushed position. In fairness to the design and the plastic used, a diaphragm can normally be expected to last several years working many times a day, 365 days a year. There are many other flush devices these days including the flapper but the siphon, whose basic design is much older than any of us, still remains in use because its very reliable and very simple.

 

[ey143]

Does the siphonage concept also work for the flapper type system - if not how does that work and is that also prone to failure like this one after a few years?

 

[Belboz]

Does the siphonage concept also work for the flapper type system - if not how does that work and is that also prone to failure like this one after a few years?

The flapper is a simple affair.

Basically, at the base of the downpipe inside the cistern there is a round hinged flap with a rubber gasket. This just sits over the outlet and the pressure of the water in the cistern keeps it sealed. When you press the flush, a chain pulls up the flap and lets the water out. The flap falls back down and the cistern fills with water - keeping the flap sealed again.

Basic explanation and probably not the best but I replaced my syphon with a flapper years back and have had very few issues ever since.

Example pic below.

B

http://www.screwfix.com/p/push-button-flapper-toilet-cistern-valve/93300

 

[Bosswhite]

Does the siphonage concept also work for the flapper type system - if not how does that work and is that also prone to failure like this one after a few years?

A new diaphragm can fail at any time if debris gets into the cistern or "Loo Blue" is used in the cistern (to make the water look pretty )

Flapper valves are simple, easy to fit, one just has to make sure the chain connecting the lever or push button is the correct length,
Water flow into pan can be regulated by length of time the lever or push button is operated. Its a question of getting used to it.

If a customer has a syphon Diaphragm problem I change it for a flapper valve. Had no complaints yet .

 

[ey143]

Thanks everyone for their comments. I learnt something from this. One last question: what would a reasonable plumber have charged either to replace the diaphram or to replace they whole syphon if the diaphram alone couldn't be replaced. Say London rates.

Cheers again.

 

[Belboz]

Thanks everyone for their comments. I learnt something from this. One last question: what would a reasonable plumber have charged either to replace the diaphram or to replace they whole syphon if the diaphram alone couldn't be replaced. Say London rates.

Cheers again.

No such thing as 'a reasonable plumber' in London

 

[Bosswhite]

Thanks everyone for their comments. I learnt something from this. One last question: what would a reasonable plumber have charged either to replace the diaphram or to replace they whole syphon if the diaphram alone couldn't be replaced. Say London rates.

Cheers again.

If it was Pimlico Plumbers, you would need a Second Mortgage !!

 

[ey143]

I'm guessing about £50 plus parts for average cost?