Dual haskel problem


No, I’m in Maine.

1 Like

Now that I think about it, the iron fist ex40 I was running had twin Haskell’s in the closet, but was only using one.

The other was plumbed in to be used as a spare should the need arise.

Presumably someone had decided two wasn’t much better than one, much as @dabgrow did.

Note: the pumps were on independent compressors. As were the pair working together on a much smaller ETS machine across the isle.

It was one of the ETS compressors that blew the breaker.

1 Like

Wanted to touch base here as I’d been away on a road trip over the weekend and was briefly chatting with @Doctorsmith4200 over instagram DM’s before I’d made it back home to a keyboard. For anyone else like me who’s searched the Haskel threads for information on troubleshooting.

First off we had some questions about the Haskel pressure ratings and I provided the same suggestion I would to anyone new to these pumps, read the brochure and manual.

Brochure: https://www.haskel.com/wp-content/uploads/EXT420-Brochure11.pdf

The brochure tells you what type and size fittings are on the pump (1/2" tube JIC, 37º flare). It has the inlets and outlets labeled (although the Gas Outlet Port on the right-hand side is mislabeled as inlet). These ports are tagged on the pump with metal safety wire attached placards, so it’s hard to mess up (unless someone’s removed the tags).

It tells you that you need an air speed control valve, like a Gate Valve or a Globe Valve.
Not a ball valve. I’ve seen this too many times. Ball valves won’t let you accurately meter airflow.
It tells you the airflow requirements -25 CFM of air at 90psi or higher. Compressor located in a separate room from the extraction room.

I asked if the hoses and fittings were put together identically as before. @Doctorsmith4200 had taken pictures before hand - a great practice. Another way is to Mark hoses and fittings with colored tape or 2 different colors of Sharpie before disassembly so you don’t mix things up.

He shared a video of the two pumps both cycling at significantly different speeds.

Asked if the pilot stems and cycling valve had been checked for lubricity and everything reported good.

I suggested to put a gloved finger over the pilot valve exhaust of a pump to stall it out for a few seconds and listen to just one pump at a time. I assumed he had a single control valve for both pumps and suggested to turn up the airflow to the “slow” pump and see if it would happily reach the target speed and run smoothly. At this point I was told the pump was taken off and out of service and didn’t spend more time talking about diagnosis. Sorry for not continuing the discussion on IG on Sunday after you told me the pump had been taken off, sorry Doctor.

@cyclopath is exactly correct with the next step. If the pump doesn’t happily pick up speed then take off the hose from mole sieve to pump and clean it with hot alcohol and pour the alcohol in a clear glass dish or jar. If there is any hint of color here that means oil was drawn through this hose and there is oil in the gas drive. Take the crossover tubes off and unscrew the check valves with a large socket or wrench and take them apart. Keep the inlet and exhaust valves separate or just clean them one at a time.

Check valves are covered in the Haskel rebuild video at 49:14, https://youtu.be/rCNbmx4f7HE?t=2954

There are only a couple parts here, the housing, a ball and two springs and some plastic seats. You don’t need to take O ring off or take the seats out of their housings like in the video - we aren’t replacing anything, just cleaning. Make sure you clean each part. I suggest using a white rag. T shirt, Diaper cloth or white lint free microfiber.

After you get the pump back together you might want to check the mole sieve and its inlet hose, and clean / replace sieve beads as needed.

If it still doesn’t pick up and get to 60 cycles a minute then its time to pull it apart and inspect the air drive barrel and piston o ring, and the gas drive section walls and seals. Aka rebuiild. If you aren’t comfortable with this stuff then I suggest FLW for the rebuild on the West coast.

@extractionjackson207 I ran an EX40 with dual haskels worked just fine with a single regulating valve and then a tee going to equal length lines to the pump air inlets. I disagree about opposing stroke. i think the pumps scavenge from each other on opposing stroke. I had slightly higher recovery rates when the pumps were in sync. I would tap the pilot stem exhaust to get the pumps in sync.

I believe a better way to plumb these pumps would be to have the top cap of the molecular sieve have 2 outlets, then run independent hoses to each pump. That way the molecular sieve acts like a ‘surge tank’ like the intake manifold on a car, for the pumps to draw from without scavenging from each others inlet strokes as much.

@dabgrow Talked with Iron Fist about that and their thoughts are just not enough vapor being created with the size of the collection vessel for 2 pumps to have enough vapor to pump without scavenging on pump stroke being a major detriment to pumping efficiency. Seems to be an issue with the EX 10 sized vessel only. The 20’s and 40’s still come with 2 pumps, but the 10’s now come with a single pump.

@cyclopath I saw higher recovery rates with 2 pumps in good shape compared to 1 off and one running. But only when there was adequate heat to maintain pressure aka vapor production in the collection vessel.


@SamuraiSam: Excellent write up!

Thank you!!


Thank you for all the help I have a new haskel being delivered tomorrow and I am sending in both of the ones I have now for rebuilds. I am just going to run one pump until I get the rebuilds back. Is there anything I can do to stop oil and crud from being sucked past the desicant beads

1 Like

demister mesh before beads and/or avoid bubbles+splashing out of your recovery vessel


Ensure there arent any restrictions in the mole sieve. If using a sock to hold the beads, leave an inch or two of excess sock length above the stem inside the mole sieve to mitigate the oil buildup. Does your mole sieve have a gauge? If so, check it out during recovery. lower pressure on the outlet side of the mole sieve than in the collection vessel indicates a restriction between the pump and the collection vessel. Inspect your hoses and fittings, particularly the 90° on top of the vessel. I’d see a lot of crystalline buildup inside the fittings. How high does the solvent/ oil level get in your collection vessel? High activity and high levels make carryover more likely.

What’s the sustained pressure in your collection vessel during recovery? Any condensation or frosting issues on the outside of the vessel? If so simply turn the pump speed down to pull less through. If possible I liked to leave the pumps off when receiving solvent from the columns to minimize carryover.


I should’ve elaborated more. I don’t disagree with what you said. The reason I use ball valves is because I regulate each pump individually. I failed to mention that. The opposing strokes can compensate for borderline cfm output from the air compressor with check valves (the check valves eliminate scavenging). A compressed air accumulation tank will do wonders as well to not starve the pumps as well.


@cyclopath in OK. Curious if you offer professional consulting services new start up? If possible DM me.


Yes, sorry I missed this. Let me know what you’re looking for. If I can’t help I probably know someone who can.