how much air should be in 3/16 line?

[raptorfan85]

I built a shurflo system for this year. Its 3/16 line with 5/16 drops on a very flat area. I have 3 runs of 26, 22 and 12 taps for a total of 60. I put my taps in yesterday to get everything set up for the real season coming in about a week... this is my first year doing tubing or vacuum, so Im not sure what I should be looking for. It seems like I have a lot of air in the lines. I know some gas comes from the trees but how much? I walked the lines today and didnt see any areas where the bubbles were "racing". Seems pretty steady for the whole run. I know I have one leaky tap, bubbles coming out of the drop, but Im not sure what to do about that. Im putting a couple videos for people to see. Does it seem like a lot of air in the lines? Its pulling 15 hg with a recirculation line, which seemed fairly good to me. Whats everyones thoughts?

https://youtu.be/g--q9UzRcns

https://youtu.be/lubg1m7aurs

[maple flats]

That close to a diaphragm pump may be changing how it looks, but in my 3/16 lines (which have mechanical vacuum on the mains) are often about 50/50. The sap might be about 2-3" long "slug" then about the same of air. They move along at a steady pace. In my 5/16 where they enter the mains thru a 14-18" long loop is near the same ratio but in those the sap is maybe 1'1.5" long, then about the same for air. In the 5/16 coming off the hill it can be different because the air can and does pass the liquid. The more that happens the longer each is as it goes thru that final loop to the main. In 3/16 the air does not pass the sap so depending on how fast the flow is the ratio may change but it is still a continuous procession thru the tubing.

[raptorfan85]

Thanks Dave. I went back out a little later when it was running a little better. Everything was moving along at a good steady pace. Seemed to be less air in the lines as well. I checked the lines a short ways back from the pump and it was similar to how you described it. About 50/50 sap and air.

[mol1jb]

How much air is a good indication but will change as flow picks up during the day. I like looking at sap speed as well. When one line is flowing much faster than another I will back track it and usually discover a small leak speeding things along.

[raptorfan85]

So I have found 2 taps that are pulling a little bit of air. If I make a loop in the 5/16 drop I can see a good sized bubble go through about every 3 to 5 seconds. I tried giving the spouts a little more of a tap but not too hard and it did nothing. One tree was large enough for 2 taps so I tried drilling a second hole and it still did the same thing. Is it possible that the spout is bad? Didn't see any cracks in it. Thought maybe it was just not sealing in the hole but it did the same on both holes. The other tap was doing the same thing but I decided not to mess with it. It seems like a pretty small leak, but should I take those taps out or leave them? I was getting upwards of 20"at the manifold yesterday.

[TreeTapper2]

I had the same issues as you today. Being my first year tubing I'm not sure what to expect or look for. Hopefully someone can offer some insight.

[kboone1]

**Disclaimer** I am by NO means a 3/16th guru, nor a scientist, but I do have 150 taps on natural gravity, and this is my second full year, so here goes a little food for thought ha-ha!

I had these same questions starting this year (heck, I still do in a way, I want to do a hybrid system next year with the Shurflo), but through some trial testing I have come to the conclusion that if you have enough drop (or I am sure vacuum from your pump), there will be trees that produce less sap and more gas than others. I have used a few trees this year as "trial" trees to see if I could get a glimpse into this a bit more, and I found that the vacuum on the lines with these trees did not change (not really a "leak"), as I still have max vac on all the lines at the top, although it did create more air space in the line, thus almost looking like it was a leak. These drops do insert much more air into the line than the others (especially on high vacuum lines it seems), however it does not seem to effect yield or vacuum on the other taps. I run 3/16 drops with no artificial vacuum due to how much elevation drop I have, so this is based only on what I have found in my lines. I am a bit OCD when it comes to knowing I am getting every once of sap I should, and I have walked my hill way more times than I would like to admit, but I really cannot see where these "more dry" trees should negatively effect the overall production, unless I am missing something that others know about, which could very easily be the case. I hope this helps ease your mind, or maybe we could get some others to weigh in!

Kody