4.2 fan not running


 
J

JimGreenwood

New member
First time builder, have the HeaterMeter 4.2 with a Raspberry Pi B.

I have my unit up and everything seems to be running properly with the exception of the fan. The HeaterMeter unit is responding properly to pit temp changes, showing fan rates from 0-100%, but I never draw current at the blower pin. I've tested the circuit backwards to the resistors and have continuity, but then I am not sure where the circuit goes next. I've confirmed that the fan itself works properly by connecting it to the 5V and GND pinouts on the RJ-45. Any tips for troubleshooting this?
 
Silly question: Are you powering the unit with a 12v supply or are you just powering it via the RasPi micro usb port?
 
JimGreenwood said:
Not silly to me...Pi. I guess that is the problem?
Click to expand...

Yes that's the problem. I built my new HM setup last week and when finished left it plugged into the USB port of the Pi for power like the instructions said, and then hooked up the fan and wondered why it wouldn't run. I used a multimeter to find a wire with 12v coming off of it, and never did, so I gave up for the night. Later in bed, I realized "duh, I'm never going to find 12v when I've only got 5v coming in over USB".

Long story short, your fan will not work without a 12v power supply plugged in.
 
ChrisMueller said:
Yes that's the problem. I built my new HM setup last week and when finished left it plugged into the USB port of the Pi for power like the instructions said, and then hooked up the fan and wondered why it wouldn't run. I used a multimeter to find a wire with 12v coming off of it, and never did, so I gave up for the night. Later in bed, I realized "duh, I'm never going to find 12v when I've only got 5v coming in over USB".

Long story short, your fan will not work without a 12v power supply plugged in.
Click to expand...

Found a 12v adapter, works like a charm. Thanks for the tip.
 
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