Here is a picture of my FARS.
I have looked around the internet and can’t find one like it. It seems to be working pretty well. Looks to have smoothed out some of the temperature errors I was having, but it needs to be tested a bit more and since today was overcast it needs to be tested on a hot, sunny day.
Yes, I know it looks like a space probe. The long bolts are only temporary until I get time to install the shorter ones I picked up at Lowes this evening.
I’m adding the design details of the Vertical Fan Aspirated Radiation Shield (pdf)
Qty — Description
1 – 10″ piece of PVC pipe, foam core pipe is best.
2 – 3″ Snap in drain inserts (Oatey)
1 – 3″ pipe coupler (used to join two pieces of pipe)
1 – 4″ PVC pipe cap
3 – 1/4″-20 Stainless steel bolts 3/4″ long
1 – Approx 80mm PC case fan
Start by trimming off the flange from one of the 3″ PVC snap in drains. This will be the Sensor mount.
Sensor mounted to the modified drain. Use the grid to zip-tie the cable.
Insert the modified drain into a piece of 3″ PVC pipe that has been cut to 10″ in length
Next mount the fan into the 3″ PVC coupler. Trim the corners to make it fit.
I glued it in place using some epoxy.
Now drill and tap 3 holes in the 4″ PVC pipe cap. These should be about 3/4″ up from the edge and spaced 120 degrees apart around the cap.
I used 1/4″-20 bolts.
Assemble the unit.
No PVC glue is required. Everything should fit tightly enough to not need it.
Put the modified drain and sensor about 2″ up inside the bottom end of the pipe.
Route the cable through the unmodified drain and insert it into the end of the pipe. Optionally add a round cutout of screen to act as an insect shield.
Next insert the pipe into the 3″ coupler on the side without the fan.
Next mount the 4″ pvc cap onto the coupler using 3 bolts inserted into the drilled and tapped holes.
there should by about 1/4″ gap all the way around the coupler/cap assembly. This is where the air exhausts.
The bolts should be tightened just enough to hold the assembly together. Too tight and you risk cracking something.
Mount the FARS as you see fit.