Cooling Fan with Thermostat Control

[DetlefSchmitz]

Actually I was going to say that if you set 0 deg then you want the contacts to be closed to turn on the cooling fan. So it sounds like the right part.

oops - too late!

 

[EFLImpudence]

D'oh. Of course. Just shows NO and NC are not the correct way to describe it.

 

[JohnW2]

The instructions state the N/O contact CLOSES with rising temperature , so what I cant figure is why at the min setting of 0 the contact is closed and then as the dial is rotated on the stat the contact opens, which is exactly the opposite to what I need.

Am I being silly or is not what you have observed correct?

If the contacts close with increasing temperature, then they would be closed when you set it to 0°, because the ambient temperature would be above 0°. If you then set it to, say 40°, the contacts would normally be open, but if the ambient temperature increased to above 40°, the contacts would then close (hence "closing with increasing temperature").

... or am I not thinking straight today?

Kind Regards, John
Edit: too slow typing (and missed a couple of posts!) again!

 

[rsgaz]

To clarify for the OP to help get your head around it, by bench testing it first, you are...

Moving the target temperature, while the ambient temperature remains the same.

But in actual, 'proper' operation...

The target temperature remains fixed, while the ambient temperature changes.

That's why it appears to work backwards at the moment.

 

[333rocky333]

We do the same thing with fans to cool the ATM pods, we use a basic central heating stat with the extra N/O contact, not all have them, satchwell do one.

 

[efiste2]

Thanks Guys, thats cleared it up nicely, my ageing brain couldnt see the wood for the tree's so to speak, Thanks again Chaps much appreciated