maximum number of taps 3/16" tubing gravity

[Worcester]

Ok so last year I asked about overloading 5/16" tubing and someone came up with about 200 taps could probably go on 5/16" tubing on gravity.

So this year I am going to run between 70 and 100 taps on the 5/16 i set up last year. I will try reducing this to 3/16" after the last tap if I have tubing left. Does anyone know the science behind this? will it actually help pull sap through bigger tubing?

However today I stretched some 3/16 around trees and it looks like i could get up to 90 taps on this 500 or so foot long line. I will go back and cut and install drops, stretch tight, and tap in the next week or two.
Should I split this in to two 3/16 lines?

What is the maximum number of taps that people have set up on one 3/16 line?
What is the science behind this?

thank you mapletrader!

[DrTimPerkins]

Should I split this in to two 3/16 lines?

200 taps on a 5/16" line is too many even for natural vacuum. If you're going to reduce it from 5/16" to 3/16" at the bottom, then 200 taps on 3/16" is WAY WAY WAY too many (did I say WAY). Even 90 taps on a 3/16" line is probably too many. Having too many on the line will result in the build up of sap and back-pressure in the system, which is BAD (it restricts the flow of sap).

Off the top of my head, I'd say that 50-70 on a 5/16" is probably near the max. About 25 taps on 3/16" is the max according to the research that Tim Wilmot (UVM Extension) has done. You should read the papers he has at http://www.uvm.edu/~pmrc (look for 3/16" tubing under "Recent Publications". If you're necking it down from 5/16" to 3/16" tubing, you should use the recommendations for 3/16", as this will determine your maximum carrying ability of the system. Think of it as a road system. Sure, maybe you can pack 200 cars on a short stretch of 3 land interstate (your 5/16" tubing) at one time, but if the road was optimized for 50 cars, the flow of traffic will be greatly reduced if you put 200 there. Now if you suddenly went from 3 lanes to a 1 lane road (3/16" tubing) with that same number of cars, it would be a huge traffic jam. The road can only carry so many cars at once, and the carrying capacity is dictated by the most limiting factor (1 one lane road, or in this case, the 3/16" tubing).

My suggestion is that you split up the lines into runs of 25 taps per line max.

[NhShaun]

Well said DrTim! So you will still get sap from your 70-100 taps on one 5/16 line, but it will be restricted and produce less than 2 lines with half as many taps.. i think.

[Worcester]

I forgot to mention that about 3/4 of these trees are red maple.

I am not sure if this matters or not? I noticed last year that they would not run as hard as sugars but the sap was nearly as sweet.

Could it be possible that I need more taps with red maple to achieve the critical mass of sap to create vaccuum?

Please anyone that has run red maple on gravity chime in

Last year I had 5/16 setup with 45 taps and it would run, we had a horrible season, but it never ran much or looked as if sap was backed up. I will try about the 70-90 on 5/16 and not use the reduction to 3/16.

The link you referenced Dr. Tim, there is mention of up to 37 taps on 3/16. it does not mention if there was reduced flow or not. If I am not mistaken the article suggested that the maximum number of taps has not been explored?

Anyone have experience of pushing the tap numbers on gravity tubing?

I will have enough material to do two lines of 30-40 taps on3/16 instead of the massive line.

[Worcester]

also how would i know if there is back pressure at the taps?

is it as simple as if i see sap backed up all the way up my drops to the tap it is too many taps, if there is space under my taps sap is moving fast enough?

Thanks for all the replies!

[Sugarmaker]

We have about 20 to 25 taps on 5/16 gravity lines. with 5% slope on lines.
Regards,
Chris

[DrTimPerkins]

Could it be possible that I need more taps with red maple to achieve the critical mass of sap to create vaccuum?

No, red maples will run just fine (almost like a sugar maple) when you have good vacuum.


If I am not mistaken the article suggested that the maximum number of taps has not been explored?

http://www.uvm.edu/~pmrc/3-16%20Tubing%20-%20Wilmot%20-%20Maple%20News%20Dec%202014a.pdf

I believe what it says is that lines of up to 37 taps have been tried. However the GUIDELINES on the third page of that article state that 15 is optimal with a maximum of 25 taps. You may certainly do more, but might not like the results.

If you create backpressure you will produce less sap. You'll know you have backpressure because when you pull the tap the sap will come out instead of air being sucked in (not a great way to check though, as you'll either kill your vacuum or lose sap), or because you just aren't getting much vacuum on your gauges (although you won't know if it is a leak or backpressure that way).

I guess I just don't understand why you'd purposely set up a system that is so far out of the specified parameters for use and expect that you'd get good results?

[Worcester]

I don't think I will set up out of the guidelines with all of this good input.

Thanks for the replies.
I guess I was trying to avoid running three lengths of 3/16 all the way to the collection tank.

This is only my second season. is running three lines of 3/16 all the way down the drop the best way to get the sap down the hill?

[psparr]

Once you get your 30' on each line you can transition to a single mainline.

[DrTimPerkins]

Once you get your 30' on each line you can transition to a single mainline.

30' of DROP that is, preferably from the first tap on the line (nearest the mainline) down.