I have three fittings on the top of my water heater processor, but have questions about what connects to each of them.

Here's how I understand it:

1. I know I need to connect one to the sight tube to allow it to fill with oil
2. I know I need to connect one to an exhaust tube to vent gases/allow air to escape while filling with oil/relieve high temp & pressure
3. I know I need to connect one to the output of the pump so the oil can return to the tank

However, when I look at tanks like Graydon's I see that he has combined the sight tube on the same fitting as the exhaust tube. That makes sense, but then what is the third fitting used for? It looks like it's also for exhaust, but that seems redundant.

Also, why do I need a ball valve on the fitting that connects to the top of the sight tube.

Can anyone clear this up for me?

Sure...
Here's a labelled diagram of what I use them for:


I use all three holes.
-Graydon

I plan to use my sight tube only to measure the amount of oil and then drain it and isolate it so that the system runs on hard pipe.

Is there any real reason to have the sight tube connect back into the tank? Seems to me that if it is open on top with a elbow so dust doesn't fall in it would work just as well.

Anyone see a downside? Known problems?

Andrew

Graydon,

Oh, by the way, thanks for all the work you put into labeling that diagram. Real helpful!

Andrew

Nah...no real reason to connect them back.
I guess it just prevents spillage.

If you could ensure you could keep it clean & free of debris, you could probably get around hooking the top of it up to the tank.

Glad you liked the diagram.

It's not "the gospel of how to build an appleseed", but just a mere example.

There's lots more here:
http://www.biodieselpictures.com

-Graydon

Must the pump return tubing/processor inlet enter the top of the reactor via the cold water inlet, or does it matter? Is there a way to remove the dip tube or does it matter if it remains in place?

Graydon, why does your Processor Vent outlet on top have a ball valve? When would you want to keep the system closed, and when would you want it open? (Basically, isn't the pressure relief valve enough to vent to the outdoors?)