Vacuum suction leak

[praz]

Hello All,

I've got a similar suction side leak issue as Dkoucky, but luckily I can isolate mine pretty much to the vacuum. Rather than hijack his thread, I'll start a new one.
A little bit about the plumbing (Hopefully my crude drawing makes sense):

                                                                  |-< Skimmer <- Underground PVC
                                |<- Pool Suction <- Jandy Valve <-|
                                |                                 |-< Vacuum <- Underground PVC
Filter <-- Pump <-- Jandy Valve |
                                |
                                |<- Spa Suction <- Underground PVC

Symptom: When I have my skimmer/vacuum valve such that the vacuum is completely turned off, the system works beautifully (except no vacuum, of course). When I turn the valve to allow a tiny bit of vacuum, I immediately hear a change in the pump and water flow, and begin to get significant air out of the filter (if I bleed it). When I attempt to turn the valve a little more toward the vacuum (or turn the skimmer all the way off), my pump almost immediately loses prime, and all pressure drops (neither air nor water comes out of the bleeder valve on top of the cartridge filter). I've checked the PVC connections at the Skimmer/Vacuum valve (and the Pool/Spa valve, though I don't believe this is part of the problem) with shaving cream, and don't see a leak. I've tried (not sure how successfully) to completely submerge the hose for the vacuum and turn the valve to add in a little suction from the vacuum, and again I get air or loss of prime (though I honestly couldn't tell you if that is air that has found its way into the hose, or if it is coming in from somewhere else).

So, several questions:
1) Can I unplug the vacuum hose from the port in the side of the pool, and somehow rig the port to be open (it has a self closing flap) and thus test the underground lines between the pool and the pump, or will this cause some type of damage to the system (having the vacuum port open with nothing attached to it)?
2) I've seen videos about putting a vacuum hose into the skimmer, and using the skimmer to vacuum. While this isn't a good long term solution at all because of the manual work involved in shifting everything around, is this something viable I could do short term to continue vacuuming the bottom of the pool every other day or something? Can my vacuum even be used in this way? (My water has turned green and murky in the meantime, probably because of un-vacuumed debris sitting at the bottom of the pool.)
3) Given the diagram above, am I missing any other possible leaks?
4) Is there anything I should check (and any easy way to check it) on the vacuum/hose?

Thanks, I really appreciate the insight and experience from everyone on the forums!

- Paul

 

[Richard320]

Option 1 is the one I would have suggested you try first, but you beat me to it. If you direct all the suction to that port without the vacuum and the bubbles stop, then you know the problem is the hose. If you still get bubbles, then I'd try coating the jandy valve with shaving cream. If it starts pulling the cream in, or you see the pump basket go white or you see soapy bubbles come out the returns, then you know the valve just needs new seals. You can also coat any plumbing joints in that section with shaving cream, too.

 

[praz]

Well, looks like bad news...When the vacuum is disconnected, and the port is left open, i get a very weak suction at the port, and tons of air in the system. I've checked all of the connections and valves leading up to the pump by coating them with shaving cream, and no holes or voids are created in the shaving cream, and I don't get foam/suds/white in the strainer basket.

Am I correct in now assuming that I have the rare underground pipe leak, or is there somewhere else I can check?

 

[Richard320]

Well, looks like bad news...When the vacuum is disconnected, and the port is left open, i get a very weak suction at the port, and tons of air in the system. I've checked all of the connections and valves leading up to the pump by coating them with shaving cream, and no holes or voids are created in the shaving cream, and I don't get foam/suds/white in the strainer basket.

Am I correct in now assuming that I have the rare underground pipe leak, or is there somewhere else I can check?

Repeat it with the hose installed. The leak gets worse when it's straining. Don't forget to check the pump basket lid and drainplug.