Electric fan preset temp?

9 LIVES

9 LIVES

Demolition Expert
Joined
Oct 29, 2006
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What would be the best temperature for the electric fans to kick in at? 180 or 210?
 
Isn't 210 a little toasty for the motor though? I would figure if it comes on at 210 then its almost to late. If it comes on at 180 it will always be running.
 
I think it depends on how well the fans work. If they can really maintain a temperature than it might be worth setting it at 210, but if they can't maintain a temperature and can only slow a temperature rise, then you will probably want to go lower.

Why can't you set them at, say, 200 or 190?
 
According to Quickserve, the thermostat is to be fully open by 203 degrees and the maximum allowable operating temperature is 215 degrees. Minimum operating temperature is 160.
 
My flex-a-lite is just a bit higher (about 10 degrees) to 190 on. They work well although I did order a spare controller as the one that comes with the kit does not have much of a heat sink and I worry about it getting fried over time.
 
Begle1 said:
I think it depends on how well the fans work. If they can really maintain a temperature than it might be worth setting it at 210, but if they can't maintain a temperature and can only slow a temperature rise, then you will probably want to go lower.

Why can't you set them at, say, 200 or 190?
Click to expand...

Its not variable. Could spend the extra money to get the variable controller if need be.
 
It wouldn't be too hard to build the circuit yourself.

The signal wire coming back from the coolant temperature sensor on the engine will vary from 0-5 volts depending on the temperature.

You need an IC chip called a comparator, and a potentiometer. A comparator turns something on and off when one voltage is higher than another. If you know that the temperature sender will have 3.4 volts at 190 degrees, you can use the potentiometer to feed a 3.3 volt source into the comparator; this will cause the comparator to output a voltage when the temperature gets around 190 degrees and outputs over 3.3 volts. You can then use the comparator to turn on a transistor that can turn on the relay controlling your fans.

If you wanted it to remain on until the temperature dropped to a level, and then turn off, you can use another comparator and potentiometer to set the lower temperature, and use a latching relay or an electronic "latch".

It's like a middle-school science project!
 
Yeah...good info and alot of help. But you lost me on signal wire!

Sounds like it would work great if I knew what a comparator,potentiometer or transistor is :doh:
 
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