Vacuum pump smoking/not pulling a full vacuum

Hey everyone. So for a bunch of reasons, I had to stop growing and making concentrates for the past 3 years. Getting married and having a kid took a lot more time out of my schedule than I expected lol.

I have an MKIII I purchased from terpp about 3 years ago. I ran it less than ten times, and since then all my equipment has been sitting in the garage for the entire time. I finally have time to start running it again, so I got everything cleaned up today and put back together. I changed the oil in my robinair (the same oil had been sitting in the pump for the entire hiatus), hooked it up to the MKIII, threw it on and started pulling a vacuum. It got down to 28.5hg easily. And then it just stalled. I noticed the pump was smoking basically until I shut the valve off on my pump.

Right now the vacuum has been holding for a few hours, going to see if it holds through the night. Anyone know what might be up? Is the pump shot? I would think not only because it has less than probably 10 hours of total use on it. I am thinking maybe there might be a leak on the actual MKIII.

Appreciate any feedback & thanks in advance.

aod

Try and isolate the problem. Connect the pump to a gauge only and see if there's still vapor coming out.
Make sure the gas ballast is closed.

RB

Ricky, thanks man. I have a spare gauge from an old cab chamber laying around, will get that hooked up.

Sorry for what is probably a dumb question, but what is the gas ballast?

Thanks.

aod

My Robinair 5CFM two stage pump doesn't have a gas ballast, probably yours doesn't either, you'd notice the knob. When I first unpacked the pump I filled it, ran it for a few minutes, and then changed the oil to remove the residual oil from the factory test. Haven't changed it since, I just keep topping it off. Something like a couple of hundred hours over several years, color looks ok, light yellow with no cloudiness.

Only time it overheated and spewed nasty smoke/dense vapor was when I forgot to either close off the vacuum chamber valve or tighten the cap on the second pump inlet, and then went off and left it. Before I noticed the open air intake, I figured I'd burned out the motor along with the pump.

^it was the other air intake on the pump. It was really loose. Thanks - working like a charm now.

Appreciate the input from both of you.

aod

AOD2012 said:

Ricky, thanks man. I have a spare gauge from an old cab chamber laying around, will get that hooked up.

Sorry for what is probably a dumb question, but what is the gas ballast?

Thanks.

aod

Click to expand...

ROTARY VANE PUMPS AND GAS BALLAST EXPLAINED
18.04.2018

What is a Gas Ballast and How Do They Work?

When a pump is evacuating a chamber, all gas molecules in the chamber are being expelled through the pump. Gases included are water vapor, solvent vapor, and or any other contaminants. An increase in pressure as the vanes rotate through the compression stage causes some of these vapors to condense. As this “wet” vapor is exhausted from the pump through the oil reservoir, the condensate remains trapped in the pump oil. This can be seen in action through the pumps’ oil level sight glass, the oil will appear light colored and or bubbly. This problem eventually affects performance of the pump, as condensate will degrade the oil’s lubricating and sealing properties. A gas ballast is a passageway that leads into the compression side of the crescent cavity allowing for small air flow. The amount of air flow allowed is controlled through a cap located on the exterior of the pump.


Using a Gas Ballast

Some pumps have three positions for the gas ballast: closed, medium flow, and high flow. Others may only choose between fully open or closed. A check-valve located between the ballast valve and compression chamber opens to allow air to enter, but not leave back out through the gas ballast opening. Opening the gas ballast allows for air to enter the compression cavity and raise the pressure to atmospheric pressure. This prevents most evacuated vapors from condensing, allowing exhaust back out into the atmosphere. Because of this mechanism of introducing air into the compression chamber, operating a pump with the gas ballast open will affect the ultimate vacuum of the pump, and this information is commonly provided by the pump manufacturer. In applications requiring a deeper attainable vacuum than with the gas ballast open, it’s recommended to operate the pump with the ballast open to minimize wear on the pump while in primary evacuation, then to close the gas ballast as pressure decreases to attain the required vacuum level. Gas ballasts can be found on higher end vacuum pumps that may be higher in cost, more effective, and longer lasting. A gas ballast is highly recommended for applications that are known to have the presence of vapors harmful to the pump, such as water or other solvents.

https://www.bestvaluevacs.com/blog/rotary-vane-pumps-and-gas-ballast-explained/