SeaLand Vacuum Generator

After flushing head I get a loud banging noise from the generator assembly. This noise does not occur during the first half of the pump cycle. At the second half the banging starts and gets louder as the vacuum pressure rises. Otherwise system works perfectly. Any thoughts would be appreciated.(2004 28 gal standard vacuum generator)

Is your vac unit attached to the holding tank, or separate? Can you be more specific as to what you mean by the "first half and second half" of the pumping cycle?

Is this a new noise, or is this the first time you're using a vacuflush?

If it's working properly, other than the noise, then take off any cosmetic covers and have someone flush the toilet while you sit near the tank and observe what it going on - see if you can isolate where the noise is coming from. First thought would be a bad motor (or mount), maybe a partially broken pumping arm. Also check the mounting bolts holding the motor on and to the vac storage unit.

NOTE!!! If you decide that you don't feel it's pumping/vacuuming properly - do not stand/sit/kneel/lay down anywhere NEAR the unit while someone flushes the toilet. I'm sure you can figure out why!

Dennis thanks for your reply. The vac gen is mounted separately. The noise started late last summer and got progressively worse. I visualy inspected motor, arm and eccentric while pump is running and found no damage or wear. It appears that the loud banging is coming from the vac gen housing under the bellows. When the pump first starts to run it runs smoothly and quietly. As the vacuum starts to rise near the end of the cycle the whole vac gen housing starts to bang and vibrate. Could it be the vacuum switch? Maybe its generating too much vacuum? Hope that helps.

Hmmm. Well, I think if it was the switch, you'd be able to isolate that as well - or at least notice it (maybe feel that that is where the sounds originates from). Is this banging different from the normal clicking you hear? Or is this clicking now louder than it usually is? It would really surprise me if the vac system created too much vacuum - the spring that controls it will only get weaker over time and thereby create less vacuum. The only way to create too much vacuum would be for the pump to continue to run. But, you're right, since the noise is building over time, it must be related to vacuum in some way.

Just to be clear: where you hear the noise coming from... You're referring to the 1-gallon (approx) "storage/holding tank"... not the housing around the bellows?

I'd check the screws that hold the motor assembly/bellows housing to the vac tank. Also check the vac/storage tank hold-down hardware. I'm thinking that maybe something is starting to flex/rub as the vacuum builds.

The vac switch is easy enough to remove and check. Verify the rubber seal (on the interior side of the switch) is in good shape. You can remove the metal plate with a small allen wrench or pliers.

I'd also pull the duck bills out and look for foreign articles.

I know I'm throwing out a lot of general ideas and not anything specific - I just keep coming back to thinking that either one of the housings are cracked (or mounting screws loose) or there is something stuck somewhere.

This problem just started on our vacuflush this weekend. I ordered a new bellows and duckbills and will replace them this weekend. I read somewhere else that this can be caused by a loose set screw on the eccentric so I’ll be checking that out too. I’ll post back here with what I find.