My 13 year old Ariston 20 MFS combi boiler recently has stopped giving hot water when the hot tap is turned on. If I waggle the auto/manual lever on the diverter valve it starts working. It is an intermittent fault but its getting more frequent. Also there appears to be a slight leak when hot water is drawn off . The heating side of the system seems to work ok.
Ariston 20 MFS Combi - no domestic hot water occasionally
- Thread starter jif06
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Is there a question in there somewhere? 
Yes, you can either replace it or you can repair it, if you know how!
Whether you should attempt it will depend on your level of DIY skill with electro hydraulic devices.
We would charge £106 inc. in London to fix it!
Tony Glazier
Whether you should attempt it will depend on your level of DIY skill with electro hydraulic devices.
We would charge £106 inc. in London to fix it!
Tony Glazier
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OK,
I am a machine tool fitter and have experience with solenoids, actuators, electronics and things like that. Will I need any spare parts or is it a case of taking the three way valve out and cleaning it? Also its right at the back of the boiler and it looks like a big job to get at it, although I do have the book that came with the boiler with brief instructions. Should I risk having a look myself or call a local engineer out . I'm a little afraid of taking it out and finding that I need new seals or gaskets and being without any heating for a few days.
I am a machine tool fitter and have experience with solenoids, actuators, electronics and things like that. Will I need any spare parts or is it a case of taking the three way valve out and cleaning it? Also its right at the back of the boiler and it looks like a big job to get at it, although I do have the book that came with the boiler with brief instructions. Should I risk having a look myself or call a local engineer out . I'm a little afraid of taking it out and finding that I need new seals or gaskets and being without any heating for a few days.
We would aim to replace the diaphragm assembly in situ but I agree its a fiddly job! Thats why we charge £106 inc.
If anything went wrong ( as it often does ) then we have all the seals and spare parts to expect to get it working again the same day to keep the client happy!
Its difficult for me to advise you!
Tony Glazier
If anything went wrong ( as it often does ) then we have all the seals and spare parts to expect to get it working again the same day to keep the client happy!
Its difficult for me to advise you!
Tony Glazier
jif06 said:
You would be better advised to change the whole valve, especially if it is leaking as well, not to difficult once you have done a few.
Isolate the boiler at the power switch, shut the mains cold off, drain off the hot tap before you start.
Good luck.
Yer. Practice on some other mug's.
I note the mfrs Instrs say take a load of stuff out to get the diverter (did the call it deviator) out. The instructions I have don't have a parts list
so I can't see what's in there. There will be a flow detector(diaphragm) which evidently operates the motor which in turn operates the diverter valve. Does anyone know which part is intermittently operating?
I have an interest in this because one of "my" dentists has one which is bound to go wrong sometime!
Since the poster is in Leeds, you can hardly accuse Tony (Agile) of touting for business. He merely gives information which is useful to the poster and others in judging the appropriate level of charges for a repair.softus said:
The installation and servicing booklet says to"remove the water unit from the appliance to get at the 3-way valve".
The book goes on to say the water unit consists of the circulator, volute(scroll), water deviation body, heating water filter, 3-way valve, by-pass, d.h.w. heat exchanger, automatic air release valve, d.h.w. flow switch, NTC probe on d.h.w. circuit, and the heating water flow and return pipes.
Local engineer coming to have a look tomorrow so I will let you know what happens
Well , it was a long wait but the engineer came to look at the boiler on the 2 Nov and only just got round to replacing the faulty part on Wednesday 30th Nov. He replaced the synchronous motor on the 3 way valve and charged 15 quid for that and 120 quid labour.(He was at the house around 3 1/2 hours) The thing is, the boiler is still leaking and he's telling me he will try to fix the leaks but cant promise anything. I thought he would have cured them because the leak is around the area of the valve at the back! Anyway, he seems a bit of a cowboy and I might have a look myself at curing the leaks. Ariston technical helpline said to go in there with a tube of LSX handy and I should be OK. What do you fellows think?
I think they're fobbing you off. I can't see LSX working in such a situation, even if you had decent access to it.
If you look back to Agile's earlier post, you will see that he anticipated that leaks might occur around the diverter valve which would have to be fixed as part of the repair. Your "engineer" did not apparently bother with this and has left you to deal with it. Stop the cheque and insist that he completes the repair.
After 4 months of emptying the bucket 3 times a week and adding pressure to the system I decided to do something about the leak.
A quick look inside and I spotted a bit of the deviator that takes a clip to hold the flow and return pipes had snapped off . M.T.S. (Ariston UK) provided me with a parts diagram(PDF by email) with all the part numbers on, and I ordered a "Deviator kit" from European Spares(£43 inc vat and p&p). To get at the deviator body I had to take the pump body off because the deviator is at the back of the boiler. Anyway, after getting everything back together the boiler worked first time apart from 1 or 2 small leaks from seals that did not come in the kit. European Spares then supplied a "seal kit x2"(£23 inc vat and p&p) which has every o ring for the boiler x2.
The boiler now works fine with no leaks apart from the pressure in the system is slowly creeping up by about 0.5 bar every couple of days.What could be causing this because otherwise everything seems to be working ok?
A quick look inside and I spotted a bit of the deviator that takes a clip to hold the flow and return pipes had snapped off . M.T.S. (Ariston UK) provided me with a parts diagram(PDF by email) with all the part numbers on, and I ordered a "Deviator kit" from European Spares(£43 inc vat and p&p). To get at the deviator body I had to take the pump body off because the deviator is at the back of the boiler. Anyway, after getting everything back together the boiler worked first time apart from 1 or 2 small leaks from seals that did not come in the kit. European Spares then supplied a "seal kit x2"(£23 inc vat and p&p) which has every o ring for the boiler x2.
The boiler now works fine with no leaks apart from the pressure in the system is slowly creeping up by about 0.5 bar every couple of days.What could be causing this because otherwise everything seems to be working ok?
Well done and thanks for coming back. (How long did it take you, sounds like a marathon??!)
Pressure slowly rising is often the filling loop "letting by", so disconnect it.
Occasionally a secondary heat exchanger can be perforated - if so, come back, we might be able to help you get one .
Pressure slowly rising is often the filling loop "letting by", so disconnect it.
Occasionally a secondary heat exchanger can be perforated - if so, come back, we might be able to help you get one .
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