As you now have a lack of flow to your heating, it seems more than just a possibility that a water leak at the gland at the motorised diverter-valve, has blown the stepper-motor drive, with some effect on the fuse, etc. I have myself had just such a leak, but in my case the blown motor did not have knock-on damage. I lost motor-function, and the main clue was a slow dripping from the valve-gland;-- so a new danfoss valve assembly, and a plumbers time req., as drain & refill + fresh anti-corrosive additive was req.
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