Low pressure systems can do funny things. We are at 34-35 degrees here and I just turned the pumps on. It is running pretty good right now. I don't know the science behind it, but low pressure systems will increase the vacuum some. We've seen it before. I am sure someone on here could explain it.
305 taps on 2 Shurflo's, 31 taps on 3/16" and 229 taps on gravity. 565 in all
Mountain Maple S3 controller for 145 of the vacuum taps
2x6 Darveau Mystique Oil Fired Evaporator w/ Smoky Lake Simplicity Auto Draw
Wesfab 7” filter press