Vaillant turbomax flow sensor

[Sharp Point]

Evening all, is it possible to test for correct operation with a multimeter, the cold water flow sensor on a turbomax combi. It uses a Hall effect sensor and has the three wires.
I did know many many years ago, but with age my mind has eradicated the knowledge.

It’s no good... this age thing, mixed with years of to much wine and Stella

Thanks

 

[AMGasServices]

I don’t know how to test it with the multimeter. However you could check it at the PCB please see image attached

 

[Vee]

You should be able to test with multimeter. The three wires will be Common, Normally Open and Normally closed. If its not labelled you will need to test across the wires with the water on and off to figure out which is which. If the values (Continuity) do not change when water flows to when water doesn't flow, then its had it.