Ariston Eurocombi help please - Fixed

Found a relay (fan relay) on the high voltage circuit board that ticked when switching off but the contact still remained stuck. Tapping with a screwdriver handle released the sticky contactors.

Replaced the fan relay on the PCB and boiler is now working properly again.

What's worse is that I replaced this relay 2.5 years ago and completely forgot that I did it.

Thanks again for all your help, hope this post might help someone else in the future.

you saying you're an electronics engineer? how on earth can you replace this component and where did you source it?

The Ariston manual had a full circuit diagram and the boiler has a diagram on it showing the major wiring. When I disconnected the cable that powered the fan and then reconnected it the boiler followed the correct shutdown re-ignition sequence. Therefore it must have some issue with the fan relays or adjoining circuit.

I had spoken to a boiler engineer who said it sounded like a sticky relay. He suggested I speak to Ariston technical department who also said it sounded like a sticky relay.
So I just listened very carefully to the circuit board and had a tap on the two relays affecting the fan on/off condition.
When I tapped the correct relay the fan switched off and the boiler then cycled thorough the correct sequence.

I de-soldered the relay from the circuit board, sourced a new relay from Farnell or Maplin (matched the specification) and just soldered the new one in.

I take pictures on my camera when I fix things like this. Found a picture and the spec. sheet for the relay on my PC dated June 2008.

Original relay on circuit board


Replaced

Hello all, I'm after a bit of help please. I'm having major problems with my boiler whereby it stays on all time. I've checked the circuit board an I can see one of the resistors has blown.

The resistor has blown so badly I'm unable to see the value of the resistor (the coloured bands) has anyone got a high quality picture that they could post/send please? Or is someone able to post the colour codes? It's the right hand board on the Ariston Eurocombi A/27.

I've zoomed in to the picture posted above but I'm unable to make out the colours.

Thanking you in anticipation!

I just simply don't believe this... it's a tall story

SEDIY said:

The Ariston manual had a full circuit diagram and the boiler has a diagram on it showing the major wiring. When I disconnected the cable that powered the fan and then reconnected it the boiler followed the correct shutdown re-ignition sequence. Therefore it must have some issue with the fan relays or adjoining circuit.

I had spoken to a boiler engineer who said it sounded like a sticky relay. He suggested I speak to Ariston technical department who also said it sounded like a sticky relay.
So I just listened very carefully to the circuit board and had a tap on the two relays affecting the fan on/off condition.
When I tapped the correct relay the fan switched off and the boiler then cycled thorough the correct sequence.

I de-soldered the relay from the circuit board, sourced a new relay from Farnell or Maplin (matched the specification) and just soldered the new one in.

I take pictures on my camera when I fix things like this. Found a picture and the spec. sheet for the relay on my PC dated June 2008.

Original relay on circuit board

Replaced

Click to expand...

Does not look anything like the realy that is removed. Even the size is wrong. So how could the black relay (looks well scuffed) be same as the one removed?

These are standard relays in different packages according to the maker.

But I have never seen any boiler maker provide a circuit diagram! Just an interconnection diagram!

Tony

Despite the naysayers, replacement relay still working fine after 10 years!
Diagrams from service manual that detail the relay;

SEDIY said:

Despite the naysayers, replacement relay still working fine after 10 years!
Diagrams from service manual that detail the relay;
View attachment 290007View attachment 290008View attachment 290009

Click to expand...

Will say this again, replacement relay is not a Siemens relay. While not disputing your boiler is working and has been for 10 years, Relay ( unspecified) fitted by you as a home owner is on a different level to me or another RGI doing same.

On many boilers the relays fitted by OEM do fail prematurely- I would replace failed relay with one installed by OEM
If you want to talk about relays, Will debate you on the operation and individual components

Always difficult to get across differing levels of experience in disciplines on a forum. I have good experience in electronics but not such a level of experience of boilers and their workings. Tony nudged me in the right direction, and an Ariston engineer nailed it with the possible relay fault. I used a slightly better spec'd relay than the original Siemens. This allowed a level of over engineering (for me) that the bean counters may not have afforded to the original engineers. Original Siemens relay was 3amp and the contacts self-welded over time, my replacement was same coil voltage and current draw but with 10amp contactors.