Kickspace 500 - Fan runs all the time

[Chris Polhhill]

Hi
My Myson kickspace 500 has a summer/winter switch and in winter position, the fan should only run when the radiator within gets heat from the boiler. In my case, it runs all the time regardless of the summer/winter switch position. I'm no heating engineer but my electrical background let me read and figure out the wiring diagram and see how it should work. I soon suspected that the low limit thermostat was faulty so out it came and as suspected a meter confirmed it was closed (short) at room temp.
I bought a new one and before I put it in, I put it on the meter and it is closed (short) as well.
Have I bought a knackered thermostat?
Have I misunderstood how it works? should the low limit thermostat be normally open?
Can anyone help please?
Chris.

 

[magicmushroom666]

The new one is probably normally closed, when you need a normally open switch. The normally closed type is quite common as they are used for overheat protection in various items. Alternatively the thing you've replaced may actually be an overheat shut off, and the thermostat control is still in there?

 

[Chris Polhhill]

Just wanted to say thanks MM666, you were spot on. Kickspace working perfectly now.
Cheers,
Chris.