Shurflo sap moving back and forth

[Bbc.396]

First time using a shurflo getting 21 to 24 inches of vacuum. Is it normal that in the line it looks like the sap is moving back and forth? Overall the flow is moving towards the pump, about 100 from the pump it's a nice slow steady flow. Cant figure out how to post a video.

[BROWN71]

Both my shurflo and guzzler do that. I figure it’s the tree’s vacuum and pump fighting it out.

[BROWN71]

Both my shurflo and guzzler do that. I figure it’s the tree’s vacuum and pump fighting it out.

[maple flats]

Normal on any diaphragm pump, as long as it goes more towards the pump you are good.

[Bbc.396]

Awsome thanks guys

[TuckerMike]

I don't want to hijack this thread, but I'm new to using the shurflo pumps this year. I've got two models; the 4008 (3gpm) and the 8000 series (1.8gpm). The best vacuum I can achieve is around 10-15". I'm running a recirc line to keep the pump "wet" and adjust the flow for max vacuum. I'm also chasing down vacuum leaks and my lines are mostly full of sap with only a few bubbles. I do see the trees and the pump fighting it out as the flow reverses occasionally on low-flow days. ...but I can't seem to get this 20" of vacuum I keep reading about. Any thoughts?

Thanks!

[Biz]

I saw a similar condition a few days ago on my setup with 102 taps. Vacuum would rise and fall, 12" to 22" back and forth over several minutes, sap flowing backwards when vacuum dropped. This obviously is not a desirable situation. I was testing a 5gpm diaphragm pump. My thought is that there was insufficient flow to maintain the vacuum. When I went to a 4008 pump (3gpm), problem went away immediately. I have been at 24-25" steady vacuum and good steady flow all weekend. An inch or two less at the end on the lines. On Friday I was getting 21-22" at the pump but it increased on Sat-Sun. I suspect that the larger pump would create good vacuum now with the higher flow rates, but there is no reason to change unless I see the pump unable to generate enough vacuum.

Dave

[TuckerMike]

I saw a similar condition a few days ago on my setup with 102 taps. Vacuum would rise and fall, 12" to 22" back and forth over several minutes, sap flowing backwards when vacuum dropped. This obviously is not a desirable situation. I was testing a 5gpm diaphragm pump. My thought is that there was insufficient flow to maintain the vacuum. When I went to a 4008 pump (3gpm), problem went away immediately. I have been at 24-25" steady vacuum and good steady flow all weekend. An inch or two less at the end on the lines. On Friday I was getting 21-22" at the pump but it increased on Sat-Sun. I suspect that the larger pump would create good vacuum now with the higher flow rates, but there is no reason to change unless I see the pump unable to generate enough vacuum.

Dave Sounds like what I am experiencing. That is why I have a recir line installed in the system, which allows the pump to operate at peak efficiency. I modulate the recirc flow to get maximum vacuum, but can only seem to achieve 10-12" at best. As you said, the smaller pump seems to do better on the lower flow lines, but even those only seem to produce 15". I used the small pump on a limited basis last year and I swear I saw 20" at some point. Makes me think I have vacuum leaks, but I'm not seeing evidence of it in the lines going to the pump. The sap is flowing slow and steady with not too may bubbles.

[bmbmkr]

There's a big difference in performance with 12V diaphragms depending on if you are runnin on a mainline or laterals into a manifold. 10" is the most I can get on 600' of 3/4 with 15 3/16 & 7 5/16 laterals coming in. I get 27" all day with my 3 laterals into a 1/2" pvc manifold. A ball valve on each lateral to isolate leaks is invaluable. This is my 4th year with shurflos & everflo pumps, none have recirc, my laterals thaw out before my tank does, so by the time the inkbird kicks the shurflo on, the lines are already runnin and the diaphragms stay wet. I run em til 30F before they shut off, any ice will catch in the strainer & the pump runs dry so it can't freeze.

[SeanD]

That's good input bmbmkr. I'm struggling to get beyond 10-12" this year. I'm sure leaks are a part, but even when I fix what I can find, 10-12" is the best I can do.

I'm finding the majority of my leaks are from the taps getting kicked out after a deep freeze. I've already had to reset all the taps twice since tapping and we're in another deep freeze this weekend. PITA.

[mainebackswoodssyrup]

Would changing to a guzzler pump help you out? We have a very similar situation to yours with 800’ of mainline, 28 laterals and 140 taps. Not sure what our Shurflo will do but we’re going to find out next week. We got 12” of vac on a very slow sap day last week. Brand new install so leaks should be minimal.