New Vacuum Question

[cur dog]

I'm new to Vacuum this year, so bear with my stupid questions. I've got a new vacuum pump rated for 8cfm and new releaser. I've got everything all hooked up and ready to roll, if we ever get a thaw. The woods are tapped and waiting. I ran the pump this morning for the first time. With my mainline valve closed, the gauge on the releaser read 27.5". With the valve opened up, after several minutes, the gauge settled in at about 20". There are about 525 taps on this system. My question is whether this sounds about right to everybody? I know there will be some loss from the taps and 100 saddles and various connections. Do I have a major leak someplace, or should I be happy with this? Thanks.

[Thompson's Tree Farm]

You should be able to get within an inch or so of what the closed off system shows. Most likely you have many small leaks if you have 20" not a single major one. Don't ever be satisfied!

[lpakiz]

I think you can do better. It will be tough to find small leaks without sap flow. I find large leaks by sight, not by hearing, because the big ones don't make much noise. So you can search for them anytime.
Small leaks are found by inspecting flow just before each lateral connects to the mainline. Look for very slow, steady movement-maybe an inch every 2-3 seconds. If bubbles and sap are traveling much faster than that, check that lateral.

[maple flats]

What length and size tubing are you using for the mains? They could also be too small. But more likely the issue is leaks.As soon as you start getting sap flow, walk the lines and check for leaks, then fix them.

[brookledge]

do you know at what Hg your pump is rated. Many vacuum pumps are rated just like air compressors, They are rated at "open flow" or zero. If you ever look at an air compressor it will have cfm's at a certain psi, the higher the presure the lower the cfm. Well a vacuum pump is just the opposite. The higher you crank the Hg. the lower the cfm. So hopefully you just have air leaks that you can fix. If you go through your tubing and can;t find any leaks and it is still at 20" then your pump is to small
Keith

[BreezyHill]

Cur dog

Sounds to me you have many leaks. I would spend so time walking in the woods listening for leaks. When the saps starts running look for little bubbles in the lateral lines and or faster than average moving sap in the lines.

If you installed valves on your main lines then isolate each one and check the vacuum gauge reaction when you turn each one off and back on. If the system is tight the gauge should not make any sudden changes after a short time of closure or on closure of the valve.

If it does you have isolated a leaky area.

Each tap will allow a minor amount of air to the system, but a drop of 7.5" is way over. I only loose about .5" on a 500 tap system. I had a 1" drop and found a connector that had failed and was wide open.

Give it a walk asap and see what you find. I am looking at a good run day today and poor tomorrow...this will give plenty of time to fix problems that are located and not finished immediately.

Good Luck!

Ben

[cur dog]

I was able to spend some time in the woods today. From 200 ft away, with def ears, I found my first leak. It was a loose clamp on a camlock coupling. I tightened a few saddles, and found 3 taps that I missed. I've now got 26" at the releaser and 22" at the end of my mainlines 3000' from the pump. I'm definately feeling better now. It warmed up enough this afternoon for the sap to run a little. I took the advice and checked some loops entering the saddle/mainline. At one location I found the sap to be zipping around the loop. I inspected the entire lateral and 5 taps for chews. After about 15 minutes of talking to myself and scratching my head, I determined I had a hollow tree. Sure enough after popping the tap and plugging it tightly into its cup, the flow slowed to a normal pace. Thanks for all the help and suggestions.

[lpakiz]

And when you get tight enough to get 26, more leaks will present themselves, because they wouldn't leak at 25, but will now. So, keep after them, it is a never-ending activity. Wish there was a fool-proof way to check saddles.
And figure out a way to remember the hollow tree, spray paint, ribbon, chain saw, something. It will get you every year.