When to shut off the pump

[Littlesap]

Hey guys,

I'm new to vac this year and wondering if there is harm in leaving the vac pump on all night even if the temp drops below 32 degrees - supposed to go down to 29 tonight around 3am.

Should I plan on shutting it off before I hit the sack or just let it run all night? What damage will I do by leaving it on?

Thanks

[Jec]

I say shut it off you will just waste power by leaving it on. The sap won't flow so there's nothing to vacuum anyway.

[Haynes Forest Products]

YES BUT............run it past freeze up so the lines are as clear as possible and turn it on early so when things thaw the sap that is in the line will have a place to go. Not all the trees in the bush start running at the same time so you want vacuum to get sucked into the line to get the process going. So if freeze up is at 11:00 and thaw is at 6:00 you do the math.

[Thompson's Tree Farm]

If the forecast is correct and the low is 29 then let it run. If you shut it off at 11 you lose a couple of hours of sap. if it is 2% worth 32 cents per gallon, it won't take many dumps of the releaser to pay for running the pump the extra few hours.

[JoeJ]

Leave to pump on, except during prolonged freeze ups. If you do the calculation for my 3 HP vacuum pump (Kilowatts = volts x amperes x .86% power factor divided by 1000)
you get 230 volts x 15 amps x .86% divided by 1000 equals 2.97 kilowatts per hour. if you run the pump from 10 PM to 6 AM, 8 hours, it costs me $3.32 at $.14 a Kilowatt. If you value your sap at $.32 a gallon it only takes 10 gallons extra sap to pay for the pump running all night. In the past 5 years since I have had my vacuum syatem, the biggest runs that I have had are the overnight runs, sometimes 1200 gallons on 900 taps. Last season I started Feb 24th and turned the pump off only once during a two
a two day freeze up and then shut the pump off for the season on April 3rd. Continous vacuum makes a lot of sap. I averaged 31.5 gallons of sap per tap last season from 924 taps. From that I made 475.5 gallons of syrup.

Joe

[maplwrks]

I agree with Joe--If you want to make sap, leave the pump on!!

[Littlesap]

OK, just wanted to make sure I wasn't damaging the trees, lines or vac pump by leaving it on during a freeze.

[ennismaple]

You could damage the pump (depending on what type it is) if it freezes solid and you don't have a vacuum regulator on the pump.