Myson Midas Si

[lingfield]

Morning All

Before you all burst out laughing I have a query regarding a Myson Midas Si combi.


I’ve seen these boilers slated on various forums but I’ve had mine since they first appeared about 30yrs ago and this is only the third time it’s thrown a wobbly.


Like various equipment the pcb is probably it’s Achilles heel but having replaced it with a brand new board the problem persists.

The DHC works fine, the CH works fine. But not simultaneously.
The problem should be obvious but having changed both the main pcb and the programme selector I’m now at the head scratching stage!

Example – Programme set to CH on / HW off – CH working fine

Switch to CH on / HW constant and the CH pump immediately switches off.
Am I missing something obvious here?

Any suggestions much appreciated.

Thank you
Ian

 

[Last Plumber]

I would say you are missing a good Heating Engineer.
You are supposed to be Gas safe registered to work on any gas appliance.
Are you registered ?
If you are you can send your card details in and join the gas safe crew

 

[Ray Stafford]

Nothing wrong with the Myson Midas SI, although 30 years is stretching it a bit.

It was the Myson Midas B (balanced flue version) that was the complete dog.

Apart from that, Last Plumber has given you the best advice you are likely to get here.

 

[lingfield]

I would say you are missing a good Heating Engineer.
You are supposed to be Gas safe registered to work on any gas appliance.
Are you registered ?
If you are you can send your card details in and join the gas safe crew

Thank you so much, that's really helpful!

 

[Rickster123]

Thank you so much, that's really helpful!

It's extremely helpful and it's the only advice that you will receive on boiler repairs from this forum.