Make Your Own Biodiesel Processor

Step 6 Pressure and leak test.

Now that you've got it assembled you need to do a pressure test. You can use an air compressor or you can run water through it, which is what we did.

Reasons for pressure testing:
-test for leaks
-gives you an idea of how to use the valves to get liquids where you want them
-to test the heating element
-to be sure everything is facing the right direction (the first time we hooked it all up the pump was facing the wrong way... oops)

Fill a carboy with water and connect a section of hose from the carboy to the intake valve. Use hose clamps to secure the hose. Be sure to have primed the pump.
Now open the valve on the carboy and the intake valve. Turn on the pump and make sure the glycerin drain and out-take valve are both closed, so water doesn't come shooting out. Also be sure that all the valves in the circuit are opened so you don't have any pressure building up. At this point it is very important to have the pressure vent on the tank open.

Mark where you see any leaks with a sharpie.

Go ahead and turn on the heating element, it may take a while to heat up. Mine didn't, 7 gallons of water takes just a few minutes to get hot. You can open the out-take valve whenever you like to get a sample of the water. Be careful, though, we're talking hot water here. You can test it with a quick-read thermometer.

When you're finished, close the valve nearest the tank and let the pump run a few more minutes before you turn it off. There's still some water behind the pump, so open the glycerin drain to drain off the cup or two of water left.

Close the next valve over from the drain and open the first valve. Have something to catch the water as it comes out.
It's probably still hot, so be careful depending on how hot you got the water.

One more thing. After testing all this be sure to open up every connection and let it dry. You don't want a drop of water in there when you make your fuel.