Ariston Eurocombi Problem

[o2x]

Hi there - been reading through the posts but not found anything exactly like my problem (or maybe it's just me being stupid!)

I have problems - with my hot water that is.

When you open the HW tap the boiler will fire up but the water will only get luke warm. Once the tap is closed the boiler stays on and must be physically switched off! It sometimes likes to fire itself up on the odd occasion too.

I have had the diaphragm replaced, but I don't really think the plumber was up to much and just replaced any old part.

Any one have any ideas?? And how much i would expect to pay to get the problem resolved?

PS. The CH seems to work OK. I've only tried it a couple of times and the rads seem to warm up nicely.

Don't know exactly which Eurocombi model it is. How do I find out? I have no manuals.

Any help gratefully appreciated.

 

[Agile]

Thats a difficult question to answer when we dont even know where you are located! Prices vary!

There are all sorts of causes for your problem and quite possibly two faults.

Changing the diverter diaphragm was a reasonable first step. But it sounds as if parts of the diverter may be seized up or very tight and not moving back to the rest position.

We charge £84 plus any parts for diagnosing the fault and fixing it if its reasonably straightforward to do so.

Tony Glazier

 

[o2x]

Thanks for your reply.

Sorry I'm based in South Wales.

To be fair to the guy he did say that it may be a whole host of problems but the Diaphragm and Diverter Valve were at the top of the list.

What I don't understand is that if the valve activates when opening the HW Tap, why does it not get hot??

The Boiler fires (I can see through the window in the front panel.

Should I leave the boiler on and check to see if the rads are warming? Would this be another clue to a faulty diverter??

 

[Agile]

I expect the lower part of the diverter is seized up and the heat is going into your rads!

If the top of the diverter is retracting then I cannot guess why the boiler is staying on after trying to use hot water. Water into electrics can cause anything though!

If we go to South Wales we always add the Toll Bridge fee to the bill!

Tony

 

[ChrisR]

I was told once how many different Eurocombi's there were. Forgotten now but I think it was 17! You have to undo the front cover/door/flap and search for a GC number if there's no name.

I don't know them all but this would apply to most:

If you can find the diverter, where the diaphragm is, you will/should/could/maybe-only-with-difficulty see a switch on the end of it which should (definitely!) operate when the tap is turned on. Usually you hear it click. That turns the boiler on.
Lots of reasons for poor HW but feel the fat pipes under the boiler, or nearest rad, with the tap still on. If anything's getting warm then the diverter valve is not doing its job.

 

[o2x]

**UPDATE**

Thanks for all the replys guys. Here's some more info regarding the problem.

Model is an Ariston A/23 MFFI

Have taken the front cover off to look whether the pin from the DV is triggering the switch when the hot tap is opened. (It is - typically the bl**dy thing has worked since i've got home - here's hoping )

Another thing - it comes on all by intself every now and again. Pin from DV is not pushing switch when this happens ????)

When the HW isn't heating up properly and the boiler stays on - the rads

do warm up.

Can understand the DV valve problem with the HW but what the bejesus is going on with the thing switching itself on???

Pressure is at 1bar on cold and rised a little when heating.

Looks like i have a multitude of problems - phoned my plumber when I got home from work. He's only gone and retired !

Oh well - back to the yellow pages.

 

[ChrisR]

Is the CH working?

 

[Agile]

Thats a good way to solve the problem to retire!

Tony

 

[o2x]

UPDATE #2

So, my excitement was short lived. It's b*ggered again.

Had a chance to have a look at the DV. It seems like it's working properly. Little pin emerges and depresses switch when the HW tap is opened. Goes back into the valve when HW tap closed.

However HW is at best lukewarm.

Boiler stays on (feeding hot water to the rads) when tap is closed.

So, that looks to have eliminated the DV??

What esle do you think it could be. Something on the PCB?? Another sensor/valve??

I'm at my wits end and have to find another plumber

 

[Paul Barker]

Because rads get warm when they shouldn't pin is sticking a little diverter valve main shaft is staying in a position that partially lines up with heating hydraulics, possibly stays on because the unwanted flow around the central heating is self perpetuating. Recon or new diverter valve should fix it. If it's the Eurocombi I'm thinking of there is a smaller flow sensing diaphragm facing the front of the boiler on the side of the diverter valve which is best renewed at the same time, it doesn't come with the new valve, disturbing it and trying to re-use would be foolish.

Do a google search for Gianoni Diverter Valves and similar key words to find cheapest way to buy.

There is every probability of a few leaks after this job is done.

 

[ChrisR]

If it's the Eurocombi I'm thinking of there is a smaller flow sensing diaphragm facing the front of the boiler on the side of the diverter valve

Nah, separate casting over on the left. May be ageing but not contributing to current problem.

 

[o2x]

What would be causing the thing to switch itself on?

Or have I got a very tiresome ghost lving in my kitchen?

 

[Agile]

The lower part of the diverter is sticking and sending heat to rads when you take HW, thats easy to diagnose!

Coming on when you dont want CH is more of a problem and my guess would be the timeclock if you have then nasty round digital one. This would need an electrical check on its contacts, not really DIY.

Tony Glazier

 

[o2x]

Thanks for all your help.

Just one final question is this:

http://www.ezypart.co.uk/parts/part_id__147

the correct DV valve for my boiler.

The last guy (the retired one) said the DV was approx £150. I don't want the next guy to rip me off on parts so I was thinking of buying it myself and paying a plumber to fit it.

 

[chrishutt]

The last guy (the retired one) said the DV was approx £150

No wonder he can afford to retire! Was that his price for fitting as well, or just for supplying? Check this and search for part no 17091.