homemade vacuum releaser using 3-gallon vauum kit?

[SapTsunami]

I have a Shurflo diaphragm pump setup that has never worked right. I can only get 5-10 inches of vacuum, even with all my inlet lines shutoff any only the recirculation line running. I have removed the inlet strainer fitting completely. It's just 4 5/16" mainlines into a star fitting and a PVC adapter into the pump. It doesn't really suck, which sucks.

I realize these diaphragm pumps are designed to push liquid, not meant to pull air.

So I'm looking at a vacuum chamber and pump kit, to make a cheap DIY vacuum releaser:

https://www.amazon.com/VEVOR-Gallon-Vacuum-Chamber-Pump/dp/B0D8T6XB7S?gQT=1

looks like it's a 3 gallon reservoir, which is plenty big for my 40 taps.
3 HPM HVAC-style vacuum pump. I calculated it could completely pump down my lines in under a minute after releasing the vacuum.
I would need to tap in a new fitting for sap inlet/outlet, as well as the float valve/timers to trigger the release cycle.
Probably should figure out a moisture trap as well.

Any suggestions or reasons why this wouldn't work?

[nhdog]

with all your sap lines shut off and if you still can't get a vacuum by adjusting the amount of feedback you still have a leak some where. if you are sure you have no leaks in the manifold and that is the case then i would that a look at your pump. you may have a bad diaphragm.

before sending $ on the kind of pump you referred to, you had best check on weather or not it is made to run full time many of them i think are not.

[DRoseum]

Agreed. Tons of people use the shurflo 4008 pumps and get over 25 in hg without issue if there are no leaks.

I second the suggestion to check the diaphram and valves in the pump head. I had one of these develop a small leak where the diaphram is sealed to the harder black plastic parts where the screws hold the diapghram to the wobble plate.