"John" writes:

IIRC the coil has four pins to a split winding a-b and c-d but I can't
recall the resistances therein. An el (very) cheapo multimeter will only
cost around a tenner or less so bite the bullet

Sounds a bit like my Honeywell model. In which case it's a couple of k
on one coil and a few more k on the other. Of the five pins, pin 3 is
earth and there is a connection between 2,4 . Rectified mains being
applied across 1,5. In my case though it got lower and ran hotter
until open circuit failure. I now have one ok winding on each of my
failed valves. Thank f**k I reinstated the immersion heater in this
house.

Jon