Loss of Vacuum

[SenecalsSugarHouse]

Hey Guys. I am new to vacuum and have an issue I hope you can help with. About a week ago we bought a sap puller diaphram pump. When we hooked it up we had about 15" on the gauge. After a few days of fixing small leaks and tinkering the gauge was reading 20". For two days it stayed at 20" but it was only about 35 degrees so very little sap came through. Yesterday it started to run good and I started it up only to get 10". I found some more leaks and fixed them but it stayed at 10. Again today it ran all day and again 10". We got alot of sap and I know it helped us anyway but I am puzzled on why we lost all that vacuum when no major leaks were found. Like I said we are new to this so any ideas would be great. Thanks, Dave

[danno]

Could be a couple of reasons. If your lines were still frozen, you would generally have higher vacuum levels because simply there are no sap lines to draw on and the frozen sap in lines will block every small leak in the system. Also, when the sap is running good, the trees will expel gasses as well as sap. In a low cmp pump, the gasses/air the vac is pulling on will reduce vac. Also, if you sap lines are undersized or you have sags, in a heavy run, I imagine sap can fill the line preventing vac from transfering through as well.

Where are you reading the reduced vac levels - at the pump or the end of your bush?

[syrup2nv]

I have a similar flaw! Im installing a dry line system w/boosters/manifolds! Vacuum cannot pull through liquid! So if there is any sags, ice jams, or full pipes of sap, the system will run lower vacuum. Im hoping this will help my sap flow.

A friend of mine installed a dry line this season on a bush of 2500 and was getting upwards of 1000gal/hr!! It nearly doubled his sap flow!! :o Unreal!!

[SenecalsSugarHouse]

Alright so I think that I've determined that you are right my 5/16 lines are filling up and backing up. Are they any ways to create space for the vacuum without splitting up the lines to fewer taps per line? Can I couple more tubing into the existing lines to create space? Any ideas please throw them out there. Just hoping for a quick fix for the last few runs. I'll split up the lines after the season to get to the 10 taps per line as reccomended.
Thanks, Dave

[JoeJ]

I don't think that there is any quick fix to solve the problem of too many taps on one lateral line. The Leader recommendations may be strive for 5 with 10 for the maximum, but if you are interested in getting the best production from your system, 3 taps per lateral is the most you want. The researchers at Proctor have proven production per tap drops off rapidly after more than 3 taps per lateral line. The more main line the better. Long lateral lines with a lot of taps decreases vacuum transfer and decreases production. Using these recommendations, my woods (978 taps) produced 34.2 gal of sap per tap in 09 and 32.4 gal in 2010

[SenecalsSugarHouse]

Ok. I figured that there probably wasn't a quick fix but I figured it was worth a shot. So now let me ask you this, suppose that you couldn't run any additional main lines, would you still gain production by breaking up the lateral lines to fewer taps but still having a long run of 5/16 with no taps on it to reach the main?

[JoeJ]

In my opinion, if you can't add main lines,it would be much better to break up the laterals with too many taps on them and add additonal laterals with less taps on each lateral. I have heard that the maximum length for a lateral with three taps should be no more than 150' for proper vacuum transfer. When I changed my wood to no more than three taps on a lateral 5 years ago, I added mainline to shorten some longer laterals. I ended up with 8 laterals longer than 100', 18 laterals 75- 100'. I just re-tubed my 948 taps last fall and used 24 rolls of tubing (plus 5 rolls for drops). That came out to an average lenght of laterals being 12.6'
Besides better sap production, shorter laterals give you an added bonus of having to repair less 5/16 tubing