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Last year was my first on vacuum and I installed gauges at the top of each run (3/16 straight to the pump) to see the vacuum accurately. What I experienced was that initially the gauges would read correctly, but eventually they would get "stuck" at a reading, never to return to zero again. I assume this is from ice damage, but it happened on the cheap "empty" gauges as well as the more expensive filled gauges so I'm just looking to see what experience others have had with this situation.
When I would have a gauge location where the gauge needed to be isolated from freezing I would install something called a "Gauge Saver" it was a fitting with a diaphragm in it they were very expensive so where I could I started installing a length of tubing made into a long hanging loop and fill just at the bottom of the loop with antifreeze. That would isolate the gauge from the main line and its product. make the loop a larger diameter and long enough and that might work??? What to use for the antifreeze in a food grade situation ???? now that is another question . Jay
Humm, Not quite sure I follow the antifreeze logic?? Wouldn't want that in the sap. Dont know what the answer is as I dont have any gages on any lines in freezing conditions. Maybe someone will come along and have a answer?
Regards,
Chris
i have gauges at the end of 2 main lines. i had the same issue. so what i did to prevent it (has worked so far) is at the end of the main, i put a 90 deg fitting and a 1' to 2' piece of tubing or pipe sticking up, then put the gauge on top of that. i found that if the gauge was too close to the pipe with sap in it, that it would freeze and stick the gauge where the pressure was. after adding the additional piece sticking up, i haven't had that issue. i have also switched to all oil filled gauges in the woods.
When I added 2,000 taps in 2013, I put cheap vacuum gauges on the 18 main lines with no cover over them. After the first year, a number of the gauges did not work, so I covered all of the gauges with small plastic bags. That brilliant idea did not work. By the next season, most of the plastic bags had fallen apart. So I replaced the bad gauges and then covered all of the gauges with small tin cans tied down with a piece of wire. A bit of a pain checking for vacuum leaks, but no more bad gauges. For once one of my brilliant ideas worked for me.
Joe
I also use the cheap non filled gauges and have not had any problems with them freezing. I transition to 5/16 tubing before the gauge and then install the gauge on an end line tee as though it was the last tap on the line. The "drop" to the gauge runs straight up against the tree to a PVC valve which is bungied to the tree with the gauge installed on the valve. I can isolate the gauge by closing the valve. Sometimes I keep the valve closed and only open to take a reading, but other times I have left it open all the time and have not had a problem either way. I also cover the gauge with one of those clear plastic cocktail glasses, which usually stays on since the gauge is tight to the tree. I think having the 5/16 tubing and the gauge elevated helps to keep any sap from getting to it and the glass protects it from rain and snow.
All of my gauges are on the end of a 2'-3' long 5/16 tube and all are tied to trees so they are essentially straight up from the lateral or the mainline they are on. While I sometimes get a gauge that goes bad, the % is low, most stay fairly accurate (meaning they continue to appear accurate) even after 2 or 3 seasons. I only use the cheapo gauges.
Put them a good bit above the connection (dropline, spout) they are near, add a loop in the line, and put a tin can over them. Those things will help reduce the chances of failure, but you'll still need to replace a few here and there due to seal failure. Buy cheap gauges and realize they may vary a couple of " Hg.