3/16 tubing - we are believers

[Snowy Pass Maple]

Colin, What kind of fittings did you use to go from the 3/16 to the 5/16 if any? I don't have more than 10-12 feet of drop to work with, but I'm still temped to try it. Did you guys try it on less than 30 feet of slope anywhere? Thanks.

We used the fittings from D&G - they are just straight transitions with single barbs on each end and a central ring/stop for the tubing between the sections. They were $0.30; tees were $0.50. Since the transition is 2x the cost of the tap, this is why getting 3/16 taps will make this approach a lot cheaper! That being said, I wouldn't try to cheap out on a fitting elsewhere unless I knew it was the exact same source - these went on easily and held really well and as so many of these threads have shown, the results have been quite variable as people figure out which parts work. I was just a really happy customer with what they supplied.

We didn't try this anywhere with lower slope - but I will certainly give it a shot next year if we setup anything with at least 10 feet drop after last tap.

I think the ultimate combo would be to combine one of these diaphragm pump setups with 3/16" tubing and enough control logic that could use the pump to get the flow started and then switch itself out of the way once the sap is running and vacuum is achieved - which would also greatly extend the operating or battery life in a remote application.

My understanding is that the only real shortcoming with 3/16" vs. traditional vacuum is that you don't get vacuum until the sap starts filling the line under gravity flow. The 3/16 would also have an advantage of a lot less volume to pump out to get the vacuum drawn initially to start things up.

At that point, it's not clear to me what else you leave on the table as compared to a high end vacuum system - but I have never worked with maple vacuum systems, so maybe I'm missing something.

[Snowy Pass Maple]

If you are talking about just going down the shelf, I don't think this will be a problem. I have something similar in my setup with all of my trees on a sloped area that ends with a 30 foot drop-off. The tubing can span 75 or 100 feet without any problems - you'll want to find a way to keep it tight.

If you avoid leaks, you will get really good vacuums at the taphole with those kinds of drops.

I'm wondering why you mention keeping it tight. Our final 250 foot run to build the vertical drop is just laying on the ground. Most is sloped, but I'm sure I have a dip here and there - I didn't worry about it as much as our 5/16 setup. My thought is that the sap loads up and moves so fast in a plug flow pushing everything through that sags may be much less of a concern than with 5/16 where they can harbor stagnant sap?

[Dave Lister]

I think the ultimate combo would be to combine one of these diaphragm pump setups with 3/16" tubing and enough control logic that could use the pump to get the flow started and then switch itself out of the way once the sap is running and vacuum is achieved - which would also greatly extend the operating or battery life in a remote application.

I was curious if “priming” the line by pouring a gallon of water into the top of the line after you put your last tap in would get everything flowing sooner?
The line is so small, it wouldn’t take a lot of water to fill the entire length of a 1000 foot long run of tubing, and then, all of the trees would immediately be on vacuum. All you would need to do is wait for the thaw and you’d be in business. With check valves, you wouldn’t even have to worry about the water going back into the tree hole.

[bowhunter]

Colin,

Thanks for the info on the fittings. I e-mailed the Shurflo tech group and it doesn't sound like their 120 volt motors will last very long....definitely not continuous service. They said they wouldn't expect a pump to last more than 3-4 months in continuous service. It didn't sound like they expected their 12 volts to do any better. I guess I'll check the Aquatec pumps again.

[Snowy Pass Maple]

I was curious if “priming” the line by pouring a gallon of water into the top of the line after you put your last tap in would get everything flowing sooner?
The line is so small, it wouldn’t take a lot of water to fill the entire length of a 1000 foot long run of tubing, and then, all of the trees would immediately be on vacuum. All you would need to do is wait for the thaw and you’d be in business. With check valves, you wouldn’t even have to worry about the water going back into the tree hole.

Interesting idea... I can't imagine why it wouldn't work. And thinking back a little more on this, I'm not even sure if this is a problem after the first run, because I often noticed a lot of sap sitting in the line when frozen, so maybe that alone is enough to get the vacuum primed again on a thaw.

[Snowy Pass Maple]

Colin,

Thanks for the info on the fittings. I e-mailed the Shurflo tech group and it doesn't sound like their 120 volt motors will last very long....definitely not continuous service. They said they wouldn't expect a pump to last more than 3-4 months in continuous service. It didn't sound like they expected their 12 volts to do any better. I guess I'll check the Aquatec pumps again.

Yea, Aquatec definitely has models rated for continuous duty. Their website has some PDF files that show this and it is based largely on temperature rise which is a function of current draw that is determined by pumphead type and pressure.

[ryebrye]

Interesting idea... I can't imagine why it wouldn't work. And thinking back a little more on this, I'm not even sure if this is a problem after the first run, because I often noticed a lot of sap sitting in the line when frozen, so maybe that alone is enough to get the vacuum primed again on a thaw.

Yes, it definitely is enough. I would check my lines after thaws and they would be back to high vacuum very shortly after the lines thawed. One of my lines has a small leak somewhere I can't hunt down - it is the only one that ever drains out completely. The other two have had a full column of sap - frozen or thawed - since mid march.