3/16 running uphill

[steve J]

The temperature this morning was right about 32 degrees. Some of my 3/16 was running but I witness one line that was sucking sap uphill. I assume there must be some trees farther up that were freezing up and sucking sap back in?

[GeneralStark]

Sap and air movement in tubing can be misleading. Sometimes the bubbles may be moving uphill, but the sap is moving downhill. It is possible that the scenario you mention could be happening, but typically you will not see dramatic backflow in the tubing when the trees freeze, especially if you are getting good vac. levels in the 3/16 lines.

[steve J]

Actually beyond seeing it in the line the 5/16 tub loop were it connects to main line I could see it being sucker out of that and into the 3/16th.

[Daveg]

The temperature this morning was right about 32 degrees. Some of my 3/16 was running but I witness one line that was sucking sap uphill. I assume there must be some trees farther up that were freezing up and sucking sap back in?
Was that happening in your lines with the check valves and did you check to see if the sap coming out at the downhill end at the same time?

[DrTimPerkins]

Sap and air movement in tubing can be misleading. Sometimes the bubbles may be moving uphill, but the sap is moving downhill. It is possible that the scenario you mention could be happening, but typically you will not see dramatic backflow in the tubing when the trees freeze,...

I agree with this post. It is most likely that you are seeing bubbles move up while the liquid is flowing down. Was there sap coming out the end of the lateral line? I also see from your signature that you're using CV spouts (?), so it seems very unlikely that there would be backflow occurring.

[CampHamp]

The temperature this morning was right about 32 degrees. Some of my 3/16 was running but I witness one line that was sucking sap uphill. I assume there must be some trees farther up that were freezing up and sucking sap back in?
If that 3/16 line saddled into a mainline, then perhaps when an ice blockage in the mainline further upstream thawed, it released lots of pressure into the system. Ice blocks in mainline have created enough pressure on my system (because the trees are forcing out sap with nowhere to go) that I've had tubing pop off of taps. So maybe a large release of positive pressure could cause what you witnessed...

[doop]

When I was installing a lateral I had finished about half of my drops (12) I was about half way up the hill about20ft up 20 to go and ran out of daylight. I came back the next day the line was still frozen and I had sap almost all the way up to top of the hill. I did have my end of line hook on with no drop on so it was open, maybe that's why it went up. I'm not sure

[steve J]

I need to update my signature I now only have CV spots on the 5/16s line !

[DocsMapleSyrup]

I was wondering about the 3/16 line backing up. The other morning, I collected my 3/16 natural vac tubing to boil that day. It was 7:30am and one of my lines has 24 trees on it and drops a total of about 60'. When I checked at the top of the ridge, my vacuum gauge was showing +6 for vacuum. I thought, that cannot be. The drop to my vacuum for the gauge is 24" above the line. When I grabbed the line, the ice cracked in the line. I had sap all the way up to the gauge. I couldn't believe it. Do you think the 3/16 was overwhelmed with the sap flow from the 24 trees the day before or possibly froze down low first, causing sap to back up to the gauge?

[mellondome]

It froze below the last tree and the sap from the trees above the freeze had to go somewhere... so up it goes. If it can get to the top of a tree, it will get to the top of your line. But inly if there is a leak to push the air out.