home Fix label Heating label_important Home Heating Systems category Ariston

Ariston Microgenus 23 MFFI PCB Defect?

Hi,

I have the very common problem of the flame detector not knowing that the burning is alight. I know it is caused by a defect on the PCB. I have already changed the PCB a few years ago and now have the same defect. I saw that Donald McNaught repaired his 28, does anyone know which resistors I should change on my 23? (they are not the same)

Clive Hancy, October 2016

home Fix label Heating label_important Home Heating Systems category Aristondone

Found out how to fix this problem on these boilers. It's really simple. I made a video to show what to do. Total cost for the repair was only 3p. https://www.youtube.com/watch?v=u-L3PzGQAa4

Clive Hancy, November 2016

Capacitors are very cheap - consider changing all the electrolytic capacitors on the circuit board on spec.

They have oiled paper as part of their construction and the oil evaporates over time and with heat - there will be perhaps three or four of them.

Use Google - select images - enter Electrolytic Capacitor and see what they look like.

Check the link in my first reply.

Good Luck..., October 2016

Sorry, I meant capacitor, I'm not really an electronics guy. Quite capable of changing a part on a circuit board though. Did that on my fridge and saved buying a new fridge. I am sure it is a component of the PCB. There are services to repair them and I am fairly sure they just change the WIMA mks4 22nf 400v but if anyone know more I would really appreciate it.

Clive Hancy, October 2016

It's very unusual for a resistor to fail - you may indeed have failing resistor(s) but you can always spot a bad resistor - they get too much voltage and burn - they first go black and then open circuit.

Capacitors by comparison are very prone to failure - they don't like heat and boilers get hot.

Consider also that the flame might be weak due to a blocked jet or that the detector may be placed in a cold spot towards the centre of the flame.

A failing resistor is your least likely cause.

Although not about your boiler - this article...
http://kaijaks.co.uk/blog/nick/2008/02/10/dodgy-old-boiler
Gives some idea about failing capacitors.

Good Luck..., October 2016

link Click here to see other fixes for Ariston.