Increase in vacuum level /day to day

[windyacres]

Airblo vane pump gave 16 inches yesterday. No major leaks discovered. Today it gave 20 ,21 with no changes to the pipeline. Readings taken an hour after startup on same gauges. How can this be,is this related to temperature. There was about 4 degrees Fahrenheit. Higher reading was a cooler day. ...?? WINDY ACRES

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[BCPP]

Just guessing but if nothing else has changed then only thing that can increase the vacuum is sealing of the system. Possibly sap drying inside very minor leaks causing them to seal up?

[windyacres]

Had a16 hour day so didn,t get to do a balance test on the 4 mains. There is also 2 8 foot ladders and a 400 gallon zero vac tank. Could the seal on tank give an intermittent leak ?

[spud]

It is the barometric pressure and or tree gas causing the problems. I deal with this myself. As the days get warmer and the sun gets hotter tree gas will bring vacuum down 5+ inches. By the end of the season I'm lucky to get 22-23 inches of vacuum. I normally run 27.

Spud

[saphead]

Noticed the same thing yesterday...warmest day off the season,vac down a little. Sun then clouds,clouds then sun,breeze from the south,hard time trying to dial in the autodraw. Did notice some gas problems in the sugarhouse but determined the cause to be "boiling sodas" !

[maplenutter butter]

Had this happen with my airablo. One of your vanes were probably stuck. If when you first started it it was cold (say 32degrees ish) ive found that to happen. Make sure to change oil and filter every season and during the season to drain off moisture in the reservoir. To help the problem i put a little buddy heater on the pump for an hour before start up and dont have that issue once running. Hope this helps.

[windyacres]

Thank you Maplenutter Vacuum back up to 20 plus inches. I believe that was a sticky vane. I have not changed the oil filter since last year and have not drained the condensation daily from tank. I will do a better job on maintenance...
WINDY ACRES

D have not drained