Shurflo 2088 Vac system?

[Biz]

Is this with your diaphragm pump? This can happen with a mainline or 5/16" line that has a droop or flat spot in front of the pump. The pump builds up vacuum pumping air until the sap moves, then flow stops when it sees another air pocket, cycle repeats. A recirc line might help but best to remove any flat spots or droops. No issues if using just 3/16 lines.

I haven't used a recirculation line in my sugarbush but if you don't want to mess with a needle valve, try a piece of thin tubing like 1/8" or 2.5mm silicone tubing inserted in series with a 3/16" recirculation line. The thin tuning acts as a fixed restriction to limit flow in the recirc line. You can add a valve to close it off when sap is flowing well.

Dave

I have to get better at using my recirc. line. I'll have like 10' of sap backed up in the mainline coming in with nothing moving. I've thought the pump was blocked, then all of a sudden, it will take in all the sap in a huge slug. Then it all starts over again. I can't quite figure it out. I'm hesitant to put a recirc. line on my remote setups because of all the adjusting needed. How often are you all adjusting the needle valve?

[Super Sapper]

I have looked at using a recirc line on my 3 systems but I do not like to leave several inches in the tank just for that. As far as the surging, the best way I have found to eliminate it is to make sure your manifold is angled into the pump suction with no flat area. I have 150 to 175 taps on each pump so if there is any flow from the trees it should stay wet enough. A recirc line may help me but I do not like the idea of leaving sap in the tank and "seeding" the new sap with bacteria.

[SeanD]

Hmmm. I had thought the surging was related to the recirc. line. Now that you mention the slope, that does make sense. There'a a flatter stretch just before the line gets to the pump. I have a remote setup with your S3 and I never noticed the surges - but I'm only there for pickups once daily. It doesn't have a recirc. line, but it does have a better slope than the one that has surges. Both are Shurflos.

That's something I'll have to explore this season. There's only so much I can do though. I just got a new, bigger tank that sits higher up than the old one. I wonder if running a dry line from the pump to just beyond the flatter stretch will help keep the vacuum pulling and cut down on the surges.

[DocsMapleSyrup]

I used to run 3/16 lines and if there is a dip, the sap will surge; however, if the line has slope to the tank, whether it is shallow or steep, it shouldn't surge when sap is running good. Usually, when sap is just starting to flow or on low flow days, the pump will surge. I put a recirc line in my setup and I used refrigerator water line with a needle valve before the sure flow intake on the mainline. I would open the valve until it just sucked enough sap out of the tank to keep the pump constantly under vacuum without surging. I let it run like that at all times. When I gathered sap, I would empty the tank and as soon as there was a little sap in the tank, the recirculation line would supply the diaphragm and it would keep the vacuum up without surging.

[BAP]

A recirculation line will help you when you need the vacuum the most. Those times when the sap isn’t running a lot because it hadn’t frozen much or at all, or hasn’t gotten going much yet. By recirculating a little sap and keeping your vacuum level up, you will get more sap out of the trees. I have a small slope on my tank and have my recirculation line, which is a piece of 5/16 tubing weighted down in the bottom of the tank. By sloping the tank a little, I only need to leave 1/2-1 gallon of sap in the tank to keep it going. Every few days, I pump the tank dry and put a little water in it to keep the pump going to eliminate bacteria buildup. 1/2-1 gallon of water isn’t going to change the amount of boiling I have to do. Also, by recirculating and getting the vacuum up, I can check the lines while the sap isn’t running much and keep from loosing any good sap runs.

[Ken18621]

My pump pulls from a manifold with 6 lines attached to it.
I have a 7th line with a needle valve that allows me to pull from the collection barrel.
I can se the valve to only draw a little from the barrel but keep the diaphragm wet and pulling higher vac.
I use this when the sap flow is slow. With good days, it is not necessary.

I have been wanting to build something like you have except with an electric sureflo. Do you have any pictures of your setup?