shurflo 4048 vacuum

[nhdog]

this year i've replaced my shurflo pumps with the shurflo 4048's. when bench testing with the manifold hooked up and with a feed back line with a valve for adjustment, what should or could i expect to get for max vacuum at the manifold ?

[Hillcrest Maples]

Not much. Shurflows move water not air very well. And a recirc line only works if you have low sap flow. Close the recirculating line, plug all your manifold ports but 1, set up as long of scrap tube as you can for the input from an 5 gallon bucket and you should be getting around 24”.

[nhdog]

thanks hillcress maple.
i do sort of the same however i plug all of my manifold inputs and use the feedback line to see just how much vacuum the pump can produce . that will let me know if i have any leaks in the manifold before i set it out and hook up my lines in the sugar bush. last night i tested my first one and got -25 1/2 in. i know now the manifold is not leaking and loses will be in length lines and fittings.

[bmbmkr]

If I keep on top of leaks, I consistently pull 25-27" with my 4048's. I run a couple of em from 25 to 150 taps. 1/2" pvc manifolds. 3/16 tubing, some on steep hills, some I'm pulling uphill. Pulling uphill isn't the best, but I tried it a few years ago and it works. It's better than carryin buckets. A couple of my sections will produce 3 gal of sap per tap a day on good runs and these aren' huge trees, average 14-16" dbh. I have never used a recirculation line either. Trees generate up to 40 psi when they thaw out. It doesn't take long for the diaphram to get wet. This is another plus with using them with 3/16. The smaller diameter DOES have more line friction that 5/16 but the shurflo overcomes this easily. Shurflos DO pull air, plenty of it. They aren't a vane pump, but show me a hi vac system for under $2k. They work very well for small sugar bushes, no power, no releaser required. A couple of my pumps also push sap uphill after pulling vacuum. They are handy!

[nhdog]

shurflo pumps while not made, i think, to pull air but if you keep the diaphragm wet they sure do. that is why my feed back line and valve are there. i have only red maple with 5/16' lines ,and only run the pumps during the day, the feed back line allows me to get thing going in the mornings. all these trees are on flat land with the feedback line it dose not take much to build up the vacuum and then the reds start running, on buckets i could hardly get anything from them.

[AlRock]

How many drops per 5/16 line are using?

Thx, Al

[nhdog]

i have only 7-10 per line and running them to 4 way mounted on the manifold. the runs are short because of how the trees are spread out.

[AlRock]

I have a flat flat area about 120yds long and 50-60yds wide. There 40-45 trees that I was gonna try 3/16 to a manifold but then thought I'd try 5/16 seeing I have the tools. Next option will be a 3/4 main but leaning towards the 5/16 and manifold right now.