Saunier Duval Semia Condens combi problem

[joinerjohn]

My brother's combi supplies CH fine, but he has no hot water whatsoever. Following the problem solving steps in the manual lead him to believe it could/probably be the diaphragm inside domestic water priority valve. However, the diagrams for the boiler don't show this part. They show something called the water valve and another called the hydraulic 3 way valve.
http://www.saunier-duval.co.uk/manuals/pdf/Semia_Condens_Instructions.pdf

Page 45 for the diagram showing the boiler parts.
What do you plumbers reckon?

 

[Agile]

I am not a plumber so my views may not count.

But I do repair boilers so I expect my views may be more useful.

Mick has in next post pointed out that it does not have a motor driven diverter valve on that model.

If you remove the clip which holds the microswitches on to the diverter valve you will see the actuator pin. This should move out about 9mm when a hot tap is operated. I expect the diaphragm inside has failed.

It might be possible to just remove the upper part to replace the diaphragm if you have a good selection of ratchet bit tools. Its probably the standard Gianoni diaphragm as used on many other boilers.

It might be a good candidate for a BG fixed price repair.

Presumably the boiler is not seeing any demand for DHW. But you have not mentioned that. Boilers are a little involved and everything has to be checked in sequence.

Tony

 

[mickyg]

Ignore Agile. He must be thinking of a different boiler.
The part isnt officially available as seperate components, only as a complete valve. You will probably find though that a standard gianonni repair kit will fit. Personally on these I would normally replace the whole valve, basically because it is an absolute sod of a job. A good 2 hrs for someone with experience of the boiler at least 3hrs for anyone else. Hence why its not a bad idea to be sure to be sure and just stick a complete valve in.

 

[joinerjohn]

Just an update on this . Following advice on here, the plumber bought the giannoni repair kit. He took the valve apart and the diaphragm was absolutely bu*****d. Replaced the diaphragm and all is well with my brother's boiler.

Thanks again to all that contributed.


PS, my brother said , it took the plumber about 2 , 1/4 hrs to replace the diaphragm.