Ariston Microcombi overheating from firing continually

[Bugwug]

Hiya Oracles,

I have an Ariston 23/27 Microcombi and it appears to be overheating whenever CH Mode is enabled.

It fires up almost immediately and appears to be on full as after some minutes the Overheat light starts flashing and in time it shuts down. Some minutes later it resumes and this cycle repeats itself.

When it does fire up it is not respecting the temperature guage on the front of the boiler, likewise, irrespective of the room thermostat, it will fire up whenever the CH is enabled. Only way i can stop the heating is by disabling the CH (if the Overheat hasnt beaten me to it!)

What would typically cause this? i would hazard a guess that its the thermostat on the temperature guage but hoping for some suggestions.

Many thanks

Nat.

 

[Bugwug]

Sorry, it works fine and dandy for the DHW (which also shuts the CH off whilst DHW is demanded)

 

[Agile]

All combis only provide one heat output at a time.

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Tony

 

[Bugwug]

Hi,

I know its supposed to work that way, but i mentioned it in case anyone wanted to know if it worked ok for DHW.

Hopefully there is an idea whats wrong with the CH firing up on full and then overheating etc.

Ta

Nat

 

[Bugwug]

Hi,

Are any of you fabby oracles able to help please?

Its not normal for CH to come on as soon as CH is enabled, it should wait for the thermostat to call for heating. It suggests something is either stuck or broken.

I hope you put your clocks back!

ta

Nat

 

[Agile]

I wonder why you keep asking for advice but ignore it when its given to you?

 

[Bugwug]

Sorry Agile but what have I ignored?

I have used this forum in the past and I do use peoples advice, I don't understand why you think I do not. Am I being confused for someone else?

My boiler fires up the CH as soon as the CH is enabled, the room thermostat is not even calling for heat. The CH then heats continually until the safety shuts it down for overheating. Once it cools it fires up again.

This isn't how it should work and wasn't the case at the end of last winter when I last used the CH. Then the CH could be enabled and heat only be drawn once the room thermostat demanded it.

Thanks

 

[Agile]

You seem to have ignored what I wrote above!

Asking for advice and then ignoring what we say does not encourage anyone to give you free advice!

Tony

 

[AlexCarp]

Bugwug, do not waste your time with this one. He says he is a professional but knew little about a Baxi/Potterton when I asked questions. He clearly came across as an amateur. I figured out how the combi operated, not him. He tends to have an attitude which is not helpful. Wait until someone more experienced comes along to answer your questions.

 

[Bugwug]

Thanks for the friendly tap on the back AlexCarp.

I was wondering why he was being so cold as clearly if something had been advised then I wasn't understanding it. I appreciate peoples time is precious which is why I try to articulate my problems succinctly in order to avoid dragging anyone into a long conversation.

Hopefully someone will either be able to explain Agiles advice more clearly or provide their own input soon.

Many thanks

Nat

 

[Agile]

I am very surprised that you are unable to see where I gave you some advice as a starting point.

Please carefully read all my posts above!

Be aware that Alexcarp above is an amateur and was unappreciative when I gave him free advice about his own boiler.

He thinks he knows better that any professional!

Tony

 

[Agile]

I am sorry Bug but I have decided to delete the advice that I gave you.

Alec clearly thinks that he knows all about boilers so he will I am sure point you in the right direction. (?)

If you really don't get anywhere then you could always email me directly.

Tony

 

[Bugwug]

Morning guys,

I appreciate you both taking the time to respond but its a shame that your own personal history is interfering with your otherwise good intentions for someone like myself or future people who may have found this thread relevant to them in weeks/months/years to come.

Agile, I know what was in the line that you have now obscured which suggests that was your advice you were referring to.

It was not clear to me as I am not a plumber/electrician but a lay person trying to establish some ideas of the fault so that when a plumber arrives I don't end up paying hundreds for a part that cost £7 as has happened to me in the past (which in hindsight I doubt was ever actually changed as the problem reoccurred and I was subsequently able to resolve by topping up the water in the system)

I can now search on your advice, thank you.


Nat

 

[Agile]

It is a relatively easy part for a DIYer to replace.

The only difficulty is the diagnosis but a test meter will usually do that.

But be aware I was only suggesting the first thing that you could check yourself. It may or may not be the problem. I have not seen your boiler myself!

Tony

 

[Bugwug]

Hi Tony,

Thanks for the confidence poke, that's appreciated! If it is a couple of screws and terminal placements then I am happy to try that. I will see if I can borrow a test meter.

I understand your final comment, not trying to snare you!

Will update the thread for others if I figure anything out.

Thanks

Nat