Is replacing the diaphragm on a 'Jetflow' siphon system in my toilet cistern an expensive job?

It would be easier and cost effective to just have a new siphon fitted. It's a Billy basic job for any plumber. Tbh a DiY'er could do it. I charge 50-70 for a job like this depending on the location and thats including materials.

It would require the cistern & pan to be seperated to allow access to the diaphragm. There maybe an issue with getting the nut & bolts holding the cistern to the pan off, due to rust. Depending on the size of the cistern, the replacement diaphragm could cost from £15 - £25 with one hours labour. I hope this helps. Handy to Help www.handytohelp.co.uk

you would be looking at around £70 - £80 total to carry out this work

you have two options, both been mentioned already, remove cistern in both instances, either cut new diaphragm from new material and refit or replace syphon completely. hours work, no call out as no diagnostic required and to replace or fix you should be looking at 65gbp

If you can get a new diaphram it should be quite cheap, you could also make one from plastic cut to the same shape, should take about 2 hours. Hope this helps Fred

The cistern has to be removed from the pan. Meaning the whole toilet needs to be unistalled. It's all standard stuff for any plumber or bathroom installer. I've changed syphons in far more complex close coupled toilets. It's about an hours work. Regards, Peter

yes that is correct ,thats why most people end up having a complete nre syphon as labour would be the same.Should take no longer than an hour at a cost of £65 supply and fit.