DC Controls help wanted...long shot...

[Karch]

I have a DC Controls FK35 controller.

The lowest setting I can set is for 148F, but I want it for about 110-120F.

Does anyone know if there is a way to do this? Perhaps adding a resistor?

Thank you.

[mitch_04]

While I can't speak for the DC Controls temp probe, most coolant temp sensors are simple devices. The resistance between ground and signal is increased or decreased when temperature goes up or down, depending on which type of sensor.

If you can unplug the temp "probe", as they call it, does it have a single wire connection or two? Does the probe screw into the block?

If it has two wires, I would measure the resistance between the two at room temperature, and then after setting the probe in a hot cup of water. Take note whether the resistance goes up or down with heat.

If it has one wire, you would want to measure resistance between where it screws in (on the probe) and the one wire. Do it at room temp and in hot water like before.

If resistance goes up with temperature, you could add a resistor to simulate a hotter temperature than actual. What I would do is heat a pot of water on the stove, very low, until the water reaches your desired "on" temperature. Measure the resistance. Next, heat up the water to 148. Measure the resistance. Take your first resistance and subtract it from your second. The difference would be the resistor you would have to put inline.

Aka at 110 degrees you have (made up numbers) 50 ohms of resistance, but at 150 degrees you have 100 ohms. 100 ohms subtract 50 ohms equals 50 ohms. You would need to put a resistor inline that has 50 ohms resistance.

Beware, however, that this will influence all of your temperatures. You could measure resistance of the sensor at temps up to the highest you think you would need, then figure out how much your resistor will affect all temperatures. The only thing I believe would happen would be fans kicking on a little sooner, but just be aware of it.

If your resistance goes down when temp goes up, then a resistor would not help you.

[Karch]

Thank you very much.
It is two wires, and I thought that was the proper way, but I wasn't getting the results I expected. I'll have to try again with the temp probe.

Thanks.

[Karch]

Update:

32.5F = 300 k-ohms
70F = 29 k-ohms
164F = 15 k-ohms
207F = 6.4 k-ohms

[Karch]

Happy to report I was able to succeed.

I wrote to Baskin twice and no response yet, first time was over a week ago.