Is there a list of trouble-shooting tips for diaphram vacuum systems?

[NTBugtraq]

I was told all I would have to do is walk the lines and I'd hear leaks, but alas, this isn't true in my bush. Perhaps its because its near a highway, or that many of the taps are at heights that require a ladder to reach, but I've walked the lines when I had 0" and heard nothing. We ended up capping Y's to isolate which artery (3/4" that Y's into the 1" mainline) had the leak. That's a lot of work (next year I am going to put shut-off valves at every entry point to the mainline.)

On another note, my sap is coming into the vacuum booster in "waves", like an ounce at a time, with maybe 3-4 seconds between dumps. I wondered if this means I have an area in my main line that is full, such that no air is passing. I know I have at least one spot where my mainline somehow got wound entirely around the wire. I was reading about wet/dry systems and wondered if maybe I should run a piece of 5/16" above my 1" main over the area I suspect might be filling??

[donniet22]

Do you have a check valve installed? I know with no check valve you wont build any vac...

[NTBugtraq]

Do you have a check valve installed? I know with no check valve you wont build any vac...

Yes, there is a check valve between the vacuum booster and the pump, and another after the pump before the storage tank sump.

[Quabbin Hill Farms]

There should a rubber check valve at the inlet and outlet of the pump they open and close with the suction created by the pump. If these aren't installed the pump won't create any vacuum. Take off the inlet piping and put your hand over if you have a vacuum gauge on the inlet side it should jump to -15 to -20 if the pump is working properly.

[NTBugtraq]

The check valves aren't the issue, they're installed as prescribed, and visibly functioning (they are made of clear plastic so I can see them operating).

So here is my first stab at a Low-Vac FAQ:


Bubbles are good, but a "lot" of bubbles means there's a leak
Walk the main line and/or arteries, and look for a lot of bubbles at lateral connections, it means there's a leak on that lateral
Hearing leaks is very dependent on things, if you're too close to a highway, or the taps are too far off the ground, you won't hear them
The inches your meter says makes no difference if there's no sap coming into the pump. Only worry when there is liquid sap coming to the pump
Always check your end plugs/caps first, then look for drops you never drilled
Unless you have a mouse in your line, crap in your laterals will get sucked into an artery and then your main. Check your filter screens daily
Always be looking for damage to laterals that can be made by porcupines, coons, and other critters
Put a shut off valve on every line that connects to your main, you can often figure out where the unheard leak is by isolating an artery (take it out of the equation by closing its valve)
If you think you have things in the field tightened up, it may very well be a bad diaphragm...not that there is anyway to check that that I know of. So a shut-off valve before your pump might let you check if the diaphragm has a leak
Using ties on your main and arteries every 18" helps to ensure you don't end up with sags that could prevent air from travelling over the sap
Vacuum recovery is very quick, in stages, like 0"-10" should be quick (like 10-15 mins), but above that it takes longer. Be patient
If your diaphragm has any damage, there will likely be some sap on the outside of the diaphragm