Ariston Micro Microgenus 23 MFFI - intermittent hot water

[thewitmeister]

Wonder if anybody could please help:

I have an Ariston Microgenus 23 MFFI, and have now had a few Plumbers/Engineers to now look at this problem. They have spoken to Ariston technical helpdesk and changed parts as recommended, but still to no avail. So I am keen to rectify this without changing unnecessary parts.

The problem:
- In the kitchen (where boiler is located), when you just run the hot water, the water is scalding, and is not regulating, even with the hot water dial on the boiler turned down to number 2.

- During the hot water being run, the boiler is continuously firing up, then stops firing and then fires up again every 1-2 minutes. Again water stays scalding.

- Temperature lights on boiler continues all the way up to 70, then back down, and then back up to 70 during this.

However, in the bathroom when having a shower or running the bath, the water goes from scalding hot to freezing cold, and this cycle continues for the duration of the shower, despite the temperature/valve on the shower being set to its hottest.

Would be grateful if anyone could shed some light, or have any ideas on this, then it would be most appreciated. It has been cleaned out recently and also had the Fan Pressure Switch changed (as advised, but made no difference).

 

[twgas]

has any the "professionals" you've had look at it checked water AND gas rates/pressures? Once these are correct then proper diagnosis can be undertaken, if there is still a problem.

 

[Agile]

Wonder if anybody could please help:

I have an Ariston Microgenus 23 MFFI, and have now had a few Plumbers/Engineers to now look at this problem. They have spoken to Ariston technical helpdesk and changed parts as recommended, but still to no avail. So I am keen to rectify this without changing unnecessary parts.

I would say that you have had several nupties who are so incapable that they cannot diagnose a simple fault ! Even though its supposed to be their livelyhood!

How did you choose them?

 

[thewitmeister]

I'd probably just like to add that the Heating/Rads are all fine - no issue with the heating side of things, just the hot water.

The pressure has been checked, and all ok.

The engineers I've had thought it could be the heat exchanger, but after speaking to Ariston 6, 7 times, they said it wouldn't be, and kept pointing to the Fan Pressure Switch, which obvioulsy didn't solve the problem once replaced.

Another option was to replace the Plate Heat Exchanger, and another has been a circulation problem. Again, no definite answers.

 

[Agile]

How did you choose them?

I asked you a very simple question about the engineers but unfortunately you chose not to answer it.

Any engineer who needs to call the manufacturers because he does not have the required skills to diagnose a simple boiler fault on hos own is always suspect!

Tony

 

[thewitmeister]

Thank you Tony. The engineers are through a firm that have carried out some other work for me. They don't deal with Aristons alot, so the call was to clarify, but even then, Ariston have given them the wrong info.

Do you know what the fault could be?

 

[A1900]

Hi

My folks seem to have a similar problem, in that the water intermittently flows hot and cold. the boiler is the Ariston Microgenus 27 MFFI. Central heating works fine. I had an engineer fix the problem earlier this year but unfortunately cant get hold of him again. All he seemed to do was clean out the heat exchanger and replace a small component possibly a pressure or thermostat valve - he seemed to exactly know the fault and took him easily under an hour. I don't mind giving this a go if i new the part etc so wondered if any of you guys can advise? Replacement of a new boiler is not affordable at the moment.

Thanks

 

[thewitmeister]

I managed to get this resolved by having the heat exchanger replaced. I had had it put in an acid bath previously but obviously didn't take long before it built up again, so bought a new heat exchanger for about £70, plus labor and now works a treat.

Hope that helps

 

[A1900]

Hi, yes that does im now more confident and can rule out other things.
Many thanks.

 

[thewitmeister]

It might be worth taking boiler cover out and getting it covered after the cooling off period

 

[thewitmeister]

It might be worth taking boiler cover out and getting it covered after the cooling off period

 

[A1900]

Hi,yeah that sounds like a good idea. Will look into it

Thanks.

 

[Agile]

I would have charged £136 for the fault that the OP had he been in our local area.

For a simple cheap boiler like that model boiler, cover is not worth it.

They might need a simple repair every year or two but with a good independent that's unlikely to be more than about £100 on average.

Tony