Ariston 23 mffi electrode problem

[bennythedip]

Looking for a bit of help on an Ariston 23 mffi microCombi. The burner will run for 5 mins then lockout. If I reset it will run straight away for another couple of minutes. While the burner is running the electrodes are constantly sparking trying to ignite. I changed the detection electrode but still the same. Anything else I can do apart from changing pcb?? Thanks for any help

 

[ShaunCorbs]

have you checked your getting the correct ma at the board?

 

[AMGasServices]

Check the condition of the wiring harness in the combustion box due to heat damage it may be causing the issue.

Also check the resistance to the air pressure switch once the boiler locks out if your getting an open circuit then sounds like your air pressure switch is on its way out.

Is the Venturi clean ?

 

[bennythedip]

have you checked your getting the correct ma at the board?

Sorry for my ignorance Shaun but what do you mean by the correct ma?

 

[ShaunCorbs]

Sorry for my ignorance Shaun but what do you mean by the correct ma?

milliamps

 

[bennythedip]

Once the boiler locks out check the resistance to the air pressure switch if it’s an open circuit then replace the air pressure switch.

Thanks for help but I’ve checked the air pressure switch, thermistor and overheat thermostat, all ok. It will run no problem as soon as I reset but the electrodes are constantly sparking all the time as if it doesn’t recognize that it’s lit??

 

[bennythedip]

milliamps

Is this coming from the detection electrode?

 

[ShaunCorbs]

Is this coming from the detection electrode?

Yes could be the wires broken / getting old

 

[bennythedip]

Yes could be the wires broken / getting old

I’ve replaced the detection electrode today but it hasn’t made any difference, that’s why I’m looking for a bit of advice, thanks

 

[AMGasServices]

Thanks for help but I’ve checked the air pressure switch, thermistor and overheat thermostat, all ok. It will run no problem as soon as I reset but the electrodes are constantly sparking all the time as if it doesn’t recognize that it’s lit??

It sounds like the rectification signal isn’t been transmitted to the PCB or it’s not registering at the PCB. Check the wiring harnesses. Before replacing the PCB speak to ariston Tech see if there any other checks that can be done.

 

[ShaunCorbs]

I’ve replaced the detection electrode today but it hasn’t made any difference, that’s why I’m looking for a bit of advice, thanks

So the new one includes the wire ?

 

[bennythedip]

It sounds like the rectification signal isn’t been transmitted to the PCB or it’s not registering at the PCB. Check the wiring harnesses. Before replacing the PCB speak to ariston Tech see if there any other checks that can be done.

Tried to get through a few times today but no joy. Eventually an agent took my name and number but I’m lucky I didn’t hold my breath waiting on call back!!

 

[bennythedip]

So the new one includes the wire ?

Yea but it only as far as a connector which then goes to the board

 

[ShaunCorbs]

Yea but it only as far as a connector which then goes to the board

I would say board then if you've replaced the cable eg new electrode

 

[Gas74]

Defo pcb mate.

 

[bennythedip]

I ordered a refurbished pcb but the one they sent wasn’t compatible . Ordered new one in local merchants and the one they gave me also wasn’t compatible ! Being a tad Soded off I just googled it and came across a you tube video which showed where the problem was on the board. All it required was replacing capacitor on the board and all sorted. Cheap fix compared to buying new board. Thanks for the help

 

[Elgordo]

Can you send a pic of capacitor location ?

 

[bennythedip]

I ordered a refurbished pcb but the one they sent wasn’t compatible . Ordered new one in local merchants and the one they gave me also wasn’t compatible ! Being a tad Soded off I just googled it and came across a you tube video which showed where the problem was on the board. All it required was replacing capacitor on the board and all sorted. Cheap fix compared to buying new board. Thanks for the help

Can you send a pic of capacitor location ?

It’s the grey one with the M marked on top of it. Think that there are also ones which are blue in the same location. Same thing

 

[Elgordo]

Thanks Benny , it might make me a hero some cold evening!