Vaillant Turbomax VUW boiler won't fire up - tries to but stops and then on/off light flashing. Manual just says this indicates the overheat themostat. Is this likely to be a failed part or something bigger? I can't reset it from the controls.
overheat thermostats do fail - happened to me once - different boiler though.
John Smith wrote on 26/09/2020 :
Have you checked to ensure the water is ciirculating through the boiler? Check the pump actually runs and is not seized. Remove the shaft end cap and check the shaft is spinning, if not it might be seized - use flat bladed screw driver to turn it and free it.
Could it be a flame detection device? I haven't looked up what kind your boiler has, but they are usually more-or-less easily replaceable.
So boiler guy reckons it's the PCB as all else is working as it should
- just not receiving the right signals.
A new one is £200 from main suppliers. But ebay has new ones at about £40 - are these really genuine parts. I guess I'd have to fit it myself as company probably won't touch them.
Try this guy. Used to be in this group and is well thought of.
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