Help figuring out new vacuum pump?

[Icetigris]

I just got this refurbished pump for degassing mold rubber and resins and what have you, but I've never worked with air compressors or vacuum pumps like this before, so I kind of have no idea what I'm doing.

Here are my questions:

1. Which hole sucks the vacuum?
2. What do the other holes do and do I need any fittings or anything for them?
3. Based on just looking at this, can you tell if this is a vacuum-only pump? The ebay listing advertised this as a pump that would be customized before shipment as a vac-only, vac/pressure, or pressure only pump. I've been trying to confirm with the seller (and ask him all these questions) but he's been very flaky and slow about it.

It appears to be a Thomas Industries 2680ce44 pump.
Here are some pics of it (I can take bigger/more if needed):

Thanks in advance for any help or insight.

 

[Rebelscum]

My take is A (in) is sucking, so hook that up to your tank and that A-C-E-G are all connected together.

B (Out) is your discharge, which you might put a silencer on as it will probably make noise and maybe even carry some particulate. And that B-D-F-H are all connected.

 

[Icetigris]

A, B, E, and maybe G (I'm not sure, it has a weird black rubber thing on it) are the only open holes. I also was reading this datasheet (I think I have a 2680, but I can't tell for sure cause the part of the label with the part number is destroyed), and I think the "in" and "out" holes might be for cooling. I guess I could turn it on and just feel which hole is sucking air the hardest, but I figured that's probably not the best idea.

 

[Rebelscum]

The data sheet confirms the groups of ports are connected. It's kind of like a master casting they drill and tap as needed, depending on the model.

None of those will be for any kind of cooling liquid, it is fan cooled..

Turning it on with nothing hooked up will do exactly what you say, one will suck in. Won't hurt to give it a whirl.

 

[Icetigris]

I figured it out; for there to be suction, the only hole that can be open is the one marked "out". I got it down to a little over 25"Hg in my vacuum chamber with just my hand over the "in" port. I'll go back to the hardware store to get a ball valve for that port tomorrow. Thanks for your help, Rebelscum!

 

[Rebelscum]

Good news. You should use brass NPT nipples and fittings. You only need 1/4" for the connections and valves. Keep in mind you'll need two valves on a T so you can bleed it down easily. If you don't have a hose to use, any 1/4" ID clear hose at home depot is fine, and just get a 1/4 brass barb to connect it to your valve with.