Thawing Mainlines

[philkasza]

We had a question whether the mainlines thaw better in the morning if we start the vac. pumps before they thaw or if we should let the lines thaw out then start the pumps. We have heard the sap will freeze under high vaccum at higher temps (maybe 34 or 35 degrees). I think the big producers have their pumps running all the time so that must be the way for most production right? We have most of the time started the pumps just as it starts to drip in the releaser but maybe it would be good to wait for a couple more hours, what are your thoughts?

Samuel

[Jeff E]

I wouldn't think vac would make any difference in thawing out mainlines. Once sap starts to run, pump should be on. The big issue really is you should work on getting your lines to totally drain, with nice slope (at least 2%) with no sagging spots. That way there is no sap sitting in lines to freeze. This will also help sap and syrup quality, as no sap will sit in the line on warm days and get skunky.

[spud]

[QUOTE=philkasza;211703]We had a question whether the mainlines thaw better in the morning if we start the vac. pumps before they thaw or if we should let the lines thaw out then start the pumps. We have heard the sap will freeze under high vaccum at higher temps (maybe 34 or 35 degrees). I think the big producers have their pumps running all the time so that must be the way for most production right? We have most of the time started the pumps just as it starts to drip in the releaser but maybe it would be good to wait for a couple more hours, what are your thoughts?



I would turn your pump on as soon as the first drop of sap is in the releaser. The vacuum will help break up the ice as it's melting in the mainlines and lateral line. You will show lower vacuum on your gauge until all the lines are thawed but no need to worry.

Spud

[unc23win]

I have mine on a timer and I set it to turn on 1 hour before the hourly forecast looks like it will be running. Some days maybe it will be a little late and another a little early, but I don't have anyone to turn it on so I will take it either way. Depending on the day part of my bush will get early morning sun while the rest will be later on. As spud says it will pull ice as well.

[Russell Lampron]

I set my woods up with dry lines so that vacuum can be transfered to the taps beyond the frozen spots. The sap will come into the releaser through the dry line until the wet line thaws.

[maple flats]

They will freeze at higher temps with vacuum. Consider a real cold bevearge, liquid until you open it, then it freezes almost instantly. When capped the pressure inside helps it not freeze, open it, pressure drops, voila, ice. The same is true in sap. However, run the pump. It will thaw and you'll be up and running as soon as that happens.
I also have wet/dry, but the taps are all in the single mains before they enter the wet/dry. As soon as a single main thaws, it will flow thru the dry line if the wet line is frozen and then go to the wet line as that thaws, via a manifold, or the incoming mains that are running.
While the sap freezes slightly sooner with vacuum, I don't want to lose any flow that is running.