Using Heater 3 as Fan 3

AndrewD2

Hello I'm rather new here. I had a bad fan in a 2 fan setup for my part cooling fan and I've just now figured out that it must have fused the mosfets for it. And unfortunately when it stopped working on Fan 0 I moved it to fan 2 and the same thing happened.

I'd discovered that I can use Heather 3 as a fan. And as far as I can tell I have it configured correctly. But I'm not sure which wires should go to which pin.

I believe the negative wire should go to pin 8 on the expansion slot, but I'm not sure where to hook the positive wire up. I've connected it to the various "VFAN" pins and it runs constantly.

My GCode is:

M307 H3 A-1 C-1 D-1 			; disable heater 3 to make it available
M106 P3 A3 S0 I1 H-1 F500		; fan 3 uses logical pin 3, which is heater 3

As far as I can tell that should be the correct gcode. So the only thing I can think of is the wires not in the right place.
Any help would be greatly appreciated. I can't afford a new board right now and I don't know anyone that could replace the mosfets.

dc42

Remove the I1 command from your M106 command.

AndrewD2

Alright, so does the positive just go to any open VFAN pin?

dc42

@AndrewD2 said in Using Heater 3 as Fan 3:

Alright, so does the positive just go to any open VFAN pin?

The positive can to to the positive pin on the heater output, assuming that if the fan voltage is the same as VIN.

Caution, on verson 1.0 Duet WiFi boards the VIN and E0- terminals are labelled the wrong way round on the underside of the board. So are E1- and VIN.

AndrewD2

Thank you very much. I'll give that a go!