Shurflo Surging.

[bmbmkr]

This was my 7th year with 12V diaphragm pumps. All shurflo 4008's now- started with everflo brand, but they just aren't as high quality or as good of a design. This surging, isn't a bad thing, it is usually the different rate of flow from the trees. I noticed it usually first thing when the trees thaw out and start running for the day, or the first day tapping. The replies about multiple lines are correct, but the perceived surging also comes from trees on one line not all producing the same amount of sap as they don't all start running at the exact same time. Each line, even with the same # of taps will have a different output due to each tree putting out more or less sap. I used to watch my pumps and think something was wrong. Aside from having leaks, or a bad diaphragm there's nothing wrong with it. The pump pulls and pulls and even though your gauge isn't consistent, you are applying vacuum to all of your taps. As far as recirculation goes, if your nearest tap is close or even uphill from your pump, the trees push up to 13PSI your diaphragms are goin to get wet pretty quick, and once wet, they will not dry out. The pump is more efficient with liquid than it is with air, but it is still much batter than gravity. With no leaks, and a properly functioning pump, you will absolutely get more sap from taps on a pump than with buckets or bags whether you see it "surging" or not.

[Hkb82]

All my lines and taps are above my pumps and some not very far away. I still found that on slow days or early and late in the day that the recirculation line kept me pulling a solid -25. Without it I’d get multiple lines having more air/gas then sap enter the manifold at the same time and get a bit of a stall. If that happens a lot I’d only hold around the -20 mark. Just the way my system seems to work but it sounds like a recirculation line would at least keep the original posters pump moving liquid. He stated it stopped pumping for a couple min and then if would start again. I’ve never had that unless it wasn’t getting sap. I think this is more his issue then the surging. Before I had the recirculation line I would get this but only loose my flow for a few seconds then it would start to pee out again. I also couldn’t get it to even -20 when that was happening. I also now can let my lines freeze up and my pump can still run without freezing till I shut it down. I find I don’t get the back pressure of sap going back into my lines when I do this. Or at least it minimizes it as much as possible.

[vach50]

Got caught up in the season quickly and didn’t have a chance to add my recirc line until today. Will be anxious to try it next year. Thanks everyone!

[82cabby]

I’m really thinking about building one of these set ups this season. Would someone be willing to post a link to a specific shurflo 4008 pump? There are several models that start with 4008 - … but then have different model numbers after the 4008. And the prices vary considerably.

Also, in Looking for a dc power supply, what kind of current draw are folks seeing or designing for with these pumps?

[DRoseum]

4008-101-A65 / E65 is the pump you want.

Max current they draw is 7.5 AMPS. You will want a 10 AMP 12 VDC power supply.