Micro leak valve?

[maple flats]

I read about introducing minimal amounts of air to enhance the performance of a sap ladder. While most of my ladders work good I have 1 that does not. It has 22-23" vacuum on it, but I still get pooling in the main. That one is a short main, only about 250'. Each end starts as a 3/4", one end is only 20' long, the other is about 180-190', then I have 3/4 x 1" SS couplings joining a40' long 1" main and I have a 4 spider sap ladder in that. The ladder is 12' high, I have good flow to the ladder, but I get poor lift in those spider legs. If I shut the pump off, let the vacuum get to zero, and then turn it on, I get full stream in the 1" line at the top of the ladder until about half of the sap has been lifted, then if gets very poor lift again. I have never needed to introduce air before, but I'm thinking this may need it. This part of the system only has about 50 taps on it. In other woods I have some ladders that are 2 side by side 3/4" lines that work well, but originally that failed here, so I changed to the spider leg type, that works the same.
What valve do you use to let very small amounts of air in near the bottom of that ladder? Is it a little needle valve? Where do you get them, part number?
Thanks

It now looks like I may get 10 days to 2 weeks more, I had to pull my few Reds and silvers about 2 weeks ago, but now the weather has gone to better sap weather and the buds on my sugars are still tight.

[BreezyHill]

Dave, I find that lines pool tat are very tight. You are able to lift the sap from 0" thru the ladder due to the system is evacuating to get to its max vac level. The sap is easily pulled up the ladder since it is in the way of air/gases behind it. When the system is near your max vac level it will slow until you reach max vac.

13900
this is one of my old injector setups. Had to ad the CV to keep out bugs and bees that would get stuck in the valve. It is a 1/8" needle valve. This one is on the end of a short lateral near the ladder. Most are on the main line on a saddle around 30' from the ladder. This gives ample room for sap to gather and the air to ride on top and force the sap down thru the riser connection.

What you are witnessing is the effect of a lack of air in the system. If your system is tight you will need an injector...if you have leaks...which most everybody does then you may not. Micro leaks on my ladder lines usually go noted but not repaired unless I have I fix some until I need to inject again.

On warm seasons like this I find it better to have a micro leak that will help clear the lines so you have less chance of sap spoiling. I find it rather exasperating to see sap sitting nearly still in 5/16 lines on a 55 degree day knowing full well what is happening in that line and then seeing your sap tank temps climb as the day progresses.

I source the needle valves at home depot in a pinch but to save $$$ I buy them
http://www.ebay.com/itm/Parker-103EF-Shutoff-needle-valve-brass-1-4-tube-X-1-8-pipe-/170280002494?hash=item27a57aa3be:m:mfqw7rRVYRyWboN XJx3IRaA

I bought a box and they combined shipping and I saved about $30.

HD valves were around $7.29 two seasons ago.

If using your 3/4" risers install a poly ball valve on each riser so you can: close them to zero out the ladder feeder line to clear a pool and to force all the sap up one riser for cleaning lines or to clear a plug.

Good Luck!

If you need other pics let me know.

[maple flats]

Thanks Breezy. On my double 3/4 ladders I do have a valve in one leg, not the other. I then can regulate if needed. Maybe I'll try one in each for next year. For those I use a Legend ball valve, they have barbed connections on both sides. Come to think of it, I did neglect to put any valves in that ladder that failed, then I removed it and installed a 4 leg spider type.
I just ordered 8 of those needle valves from Ebay. I'll try those. Not much time left, I finally got temps in the low 20's and my sugars still have tight buds. It ran a little today, hopefully will again tomorrow and most days thru 4/3 if the 15 day is close enough. It shows lots of mid 20's overnight and 40's to low 50's day, followed most days by a freeze. That should give me time to see if the needle valve helps. I may try adding a piece of cotton cloth held in place by a hose clamp to keep bugs out.

[BreezyHill]

I have thrown out the CV's but one now.

I finished changing the wet line on ladder #2 and #3 to 1/2" risers this evening just prior to dark...it did help to get 2" more past ladder #5. But the 6 way spiders were at least 1/3 plugged and two where nearly 80% due to wood chips. I will likely change all the spiders to 1/2" on the large ladders this summer. Ran out of inserts again so ball valves had to wait.

I only open most of my injectors open 1/4 turn to unseat the needle then back to 1/8 turn open and they work just fine. I do have one that is open more than 1/8 but it has a 2 season old lateral feeding in 300 taps it has to compensate for.

If you warm up the 5/16 you can screw the injector right into the tubing end for a tight fit.

[Flat Lander Sugaring]

our lines have NO micro leaks at all and we were having trouble on a 6' lift. we went up to one of our old saddles we put a 5/16 cap on and poked just an ever so tiny hole in it. What a difference now.

[BreezyHill]

Last nights low was 27.6 and it is now 34.5 and the 1/2" riser are thawed but the 5/16 lats are just starting to thaw.
Slight over cast with blue sky to the west.

[jimbison]

how far from the ladder are you putting the valve I added a new section have 20 plus on top 15 on bottom of the ladder no sap flow this is all new so very tight tried adding valve stem from tractor tire at end of main not much difference vaccum dropped 200 taps 3 6way stars top and bottom both 1 inch line

[BreezyHill]

All mine are within in 50 feet of the ladders and less if one is moved or installed in a new line. Got lyme last season and less walking in the bush is good, when I am stiff and sore. I like to see how the adjustment affects the ladder and change it down as low as is needed. To much is just a waste of vac.

[jimbison]

Will try it tomorrow thanks for the help