Shurflo pump question

[Sunnyacres]

I have about 100 taps on a shurflo 2088. I have a gauge next to the pump reading 13” and at the end of a 500 ft 3/4 mainline reading 12”. But very little sap flow if any it seems more like drips. But if I shut off and switch to using just gravity it has a consistent small trickle. Why? I know it’s still early but why does it seem like I get better flow with just gravity.

[maple flats]

It sounds like you have leaks. Check carefully to find the leaks and fix them, you should be able to get better than 12-13" vacuum with 100 taps on a 2088 if the system is tight.
Do you have a line bringing sap back from the tank to the inlet side of the 2088? They do far better if the diaphragm is kept wet.

[Sunnyacres]

I have had the same set up for three years on this mainline with the same vacuum readings every year but this year it seems like it is producing nothing this year. Just not sure why. Actually in the past I have had it connected to a manifold connecting two 500 ft mainlines with over two hundred taps and still produced the same vacuum readings. This year we are separating the lines and going to run two pumps.

[mol1jb]

If it is early I wouldn't worry about it. You will definitely get more sap on your shurflo than without.

As to your vac readings, I am in the same boat. Last year and this year I get the same vac reading on the same woods at 15" on the main. I do plenty of work on the tubing lines but it always hangs out at 15". Better than nothing.

[Super Sapper]

If the sap is not running pretty good you probably will not due much better until the flow increases unless you use a recirculation loop. If this is what you got in the past when you had good flow it could be a bad diaphragm or poorly seating check valve. Leaks would be the most likely cause though.

[Sunnyacres]

I have checked every saddle tap connector etc ten times and there aren’t any leaks. I just got another pump to try on another line so we’ll see how that works. If it pulls more I will switch out pumps to test. This is definitely the last year with these diaghpram pumps next year full vacuum system.

[Sunnyacres]

Turned the pumps on this morning and one pump has a slight trickle going into tank and the other pump you can see the sap just building up in the mainline backing up the pump and nothing coming out has any one had this happen

[Biz]

Does your mainline have a steady downward slope all the way to the pump? If it is flat or dips anywhere near the pump, you will get air pockets and the pump will have trouble pulling a vacuum. It may behave this way if no sap is flowing too but sounds like it is. You should get around 20".

Dave

[DocsMapleSyrup]

Do you have a recirculation line keeping the diaphragm wet? If not, add one. It makes a huge difference when sap is not pouring in. You will immediately notice your vacuum increase substantially. I had a similar situation before I added a recirculation line.

[Sunnyacres]

I have good slope to pumps and you can see it build up in mainlines for six or ten feet but nothing come out and then eventually it dumps like crazy but seems like it should be more steady than one big dump periodically . I will try adding a recirculate line this weekend

[DocsMapleSyrup]

When it surges like that, it is because of a slug of sap hitting the diaphragm then emptying followed by sucking gas, then another slug of sap. A recirculation line will take care of that and will hold vacuum with a more steady flow through the pump.