Size of main line for 70 taps?

[bagpiper]

I'm setting up a lunchbox vacuum at the bottom of a 4% slope. I'll have about 70 taps with 5 to 8 taps/lateral coming into the main. This is a red maple stand, so not high volume producers. My question is, should I use a 1/2 in. or 3/4 in. main line? Is one better than the other?

[wiam]

I think saddles are limited for 1/2.

[Chicopee Sap Shack]

1/2" but using 3/4 gives you more options with better parts for only a few cents more a foot


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[spud]

Minimum 3/4 but it would be better to use 1 inch. Using to small of a mainline will only hurt vacuum transfer if you were planning on using vacuum.

Spud

[Bricklayer]

I have the lunchbox. And the way I set mine up was with no mainline. I found it pulled the best vacuum when the lines were full. With a mainline you won't get that. The pump will cycle like crazy like a machine gun. I used a 6 way star fitting on the releaser with 6 laterals going to 75 taps. I was able to get a constant 20 hg. With an air pressure of 45 psi. And a super tight system. 1 leak and you will know it. Air compressor will go off like crazy and pump will machine gun.

When I originally had it set up I had a 1/2" main on it. About 100' and it cycled for hours.

I'm no expert on vacuum but the vacuum created by a diaphragm pump is different then true vacuum. It's more like using 3/16 on gravity. The vacuum is created by the sap being pulled through the tubing.

I ended up using the 100' of mainline from my sap tank to a high point in the bush. My discharge from my lunchbox 5/16 went up 40' then slightly downhill for about 700' then drained into the mainline to my sap tank. It's amazing how much that little pump will do. But it will always be a diaphragm pump so it has its limits.

[Super Sapper]

I would agree with Bricklayer, a diaphragm pump is much more efficient pumping liquid than air. The less space for air to accumulate and the faster you can remove it the better as long as you do not overload the line capacity. With the air diaphragm pump it will not cycle without flow coming in if wet but will cycle a lot if it has air. The mechanics of vacuum with diaphragm pumps and 3/16 line are different than conventional vacuum. With a pump designed to move liquid air is your enemy.

[Clinkis]

Not familiar with the lunchbox but with a Shurflo diaphragm pump you get much better results with 3/4 mainline as opposed to all 5/16 tubing.

[Bricklayer]

The lunchbox pump has very low CFM. Not even sure what the rating is on it cause the sticker was taken off it. All it is is a beverage pump that is usually used on Co2 keg systems for beer. It does work good though for a little pump.