Surflo and ball valves

[whity]

We have 3 groves we put on vacuum last season. Running Sureflo 12v diaphragm pumps with a thermostat that opens a mechanical ball valve at shut down. My question is, would we be better off eliminating the ball valve because the release of vacuum make sap flow back into the tap?

[mol1jb]

So the ball valve is currently used as a bypass once the pump is shut off?

[whity]

So the ball valve is currently used as a bypass once the pump is shut off?

That is correct. When the pump is off the valve is opened to gravity feed.

[Biz]

The ball valve bypass is a great idea, since sap doesn't flow through the diaphragm pumps when they are off. I use these on my systems. With the bypass, you won't miss a the sap flow if pump isn't running when it is supposed to. CV spouts should help prevent taphole contamination, especially if drops are not new. Turning off pump after sap has stopped flowing, or when lines have frozen, should help too, since vacuum and resulting backflow will be less. May need some trial and error to get it right, because sap in lines can keep flowing below freezing. 5/16" drops may help if you are using 3/16 tubing, just need the correct size fittings. I will be doing all of the above this year since I got burned last year by doing none of these and had a line stop running 2 weeks earlier than others.

Dave

[Maplewalnut]

I like the bypass idea. I am planning in running a shurflo on battery , is thst enough to open the valve if shurflo turns off?

[whity]

I like the bypass idea. I am planning in running a shurflo on battery , is thst enough to open the valve if shurflo turns off?
Yes it is as long as the battery has a charge. A friend told us we should use a spring return ball valve. If the battery dies it will open the ball valve with a spring instead of relying on a battery.

[Biz]

Something like this (see link) should work for the valve auto open when power is lost. For the battery power loss case, you may want a way to tell exactly when power is lost, because battery power drops off slowly. You don't want valve open and pump running on partial power at the same time. A relay that turns off below about 10 volts might work.

https://www.ebay.com/itm/1-2-Motorized-Ball-Valve-Stainless-SS-EPDM-9V-12V-to-24-VDC-VAC-2-wire-N-O-/301904928622

Dave