Before doing any maintenance, if possible flush water through the systems before working on them.  Then turn the head/toilet breaker switches to OFF.

Maintenance on head/toilet vacuum generator.  These are located below the floor in the crawlspaces accessed by hatches – one hatch in the galley for the port side (master stateroom) head, and one hatch in the guest stateroom doorway for the starboard side (guest) head.

Replacing duck bill valves.  These are one way rubber valves – four per unit – 2 each on each side of the inlet and outlet pipes connected to the vacuum generator pump.  Should be checked on a regular basis once every couple of years – or more often if using the boat full time.  Need eight duck bill spares for a complete change to both head units.  Note that these duck bill valves come in different diameters so be sure to get the right size (1 ½ “) when purchasing them. (Note: newer GH’s have larger sized valves)

The easiest way to replace these duck bill valves is to remove the complete generator and take it out on the dock where you can more easily remove/unscrew the plastic pipes containing the duck bill valves, located on either side of the generator pump housing.  (see owner’s manual) Doing it while in the crawl space is not impossible, but you need to be a circus contortionist or at the very least slightly crazy to attempt it.  Come to think of it, you have to be slightly crazy to attempt this whole operation anyway.   And if you don’t look at the whole world slightly different after you’ve done this job, then you will afterwards.  Trust me on this.

The starboard side vacuum tank generator is easily removed by removing the two bolts holding the unit to it’s support bracket on the floor of the crawlspace.  Then the unit can be moved sideways from the inside two bolts holding it down.  Leave the two inside bolts alone and only remove the two outside bolts – that are easily accessible.

To remove the generator you must first remove:

a.) both sanitary hoses- input from the head side and output from the holding tank side, by loosening stainless steel hose clamps, and twisting the hoses off the plastic pipes.  Watch out for yukkie stuff coming out the hoses when you remove them.  Have a bucket and clean up rags to clean up any spillage.

When removing the sanitary hoses, you have to slacken off the stainless steel hose clamps holding the hoses on.  The ends of these s/s clamps are sharp.  Remember, you have to bleed at least once when you are doing this.  And if you are wearing the proscribed rubber gloves (to prevent getting yucky stuff on you) they always manage to get at least one hole torn in them.  

b) disconnect the two electrical wires – one black that goes to the motor and one red that goes to the vacuum switch, and then to the motor.  Note some of these wires have quick release attachments, so don’t get them mixed up when reattaching them. (like I did)

The port side generator is more difficult to remove (due to other diabolical hoses etc that are squeezed into this same space)  and I elected to remove only the pump located on top of the generator rather than the whole generator like the starboard side.  You still must remove the two bolts that you see holding the tank to the support bracket to shift the tank slightly to the side to get to the four bolts holding the pump onto the tank.  The duckbill valves are located on each side of the pump that you now remove to the dock, so you can more easily replace the duck bill valves… four per unit, two each on each side of the pump housing.

You must first remove the hoses (as above described) for the starboard generator to remove the pump housing.

Note:  the input side of the sanitary hose is clamped to an elbow PVC pipe that goes into the vacuum tank, and can be removed with a lot (a lot!!) of twisting and pulling the elbow up — it is pressure fitted into the tank with a rubber gasket.  Just lift and twist it up and out.  It takes a lot of effort especially since you are lying on your side in the crawlspace. It only took me about 2 hours to figure this out!  You should be able to do it in a couple of minutes.

When you remove the output side hoses make sure you have a small bucket and clean up sponges or cloth to catch the two or three cupfuls of yukky stuff that is likely waiting in the hose.  It can be messy so be prepared to clean it up before going on.  Use rubber gloves and quick reflexes.  Or you will be cleaning up a mess – don’t ask me how I know this!!  It will take you longer to clean up the spilled mess than it takes to remove the hoses…  especially when you discover that you are now lying in this mess.  And you may even discover that you now know some new really bad words that should not be said out loud.  So remove any children who may be within hearing distance before starting this part of the job.  And here is where you learn how to remove all your clothes before your wife or significant other allows you to come up from out of that crawl space.  (your clothes get put into a large bag that is deposited into the furthest garbage bag on the dock)

Note:  if you must remove the vacuum switch that is located on the upper part of the tank (the L side of the tank that is sticking up), you slacken off the stainless steel 2 ½ “ clamp and then pull the switch out of the side of the tank.  It should come out easily.  Remember the electrical wires are connected to the “B” side of the switch and NOT the “A” side which are left alone/not connected to anything. We replaced this switch on each tank in March 2012 after finding that the wire connectors on the top of the switches were loose. When reinserting a new switch into the tank be careful of the two rubber gaskets and make sure they are seated correctly and not twisted out of position. I used a little silicone sealant around where the switches attach to the tank to assure there are no air leaks.

Inspect any open hoses and inside the pump housing for calcium buildup that restricts the movement of yukky stuff from the toilet to the holding tank.  I ran an old garden hose through the sanitary pipes to check for blockage. Where I couldn’t get the garden hose through the pipe, I found that replacing the sanitary hose was easier than trying to remove the calcium buildup.  (all hoses replaced with new anti smell hose in March 2012)  When installing NEW hoses, use a heat gun (or hair dryer) on the attachment end of the hose to make it easier attaching the hose.  Remember a heat gun gets things really HOT so be careful not to burn yourself.  Don’t ask me how I know this!

Any PVC Y’s or connectors can be totally cleaned out by putting them into a bath of muriatic acid – be careful and use gloves and eye glasses and DON”T spill it!  The acid eats the calcium and leaves the PVC totally like new.  Wash off the muriatic acid with a lot of water afterwards to remove the acid totally before handling anything.  Muriatic acid is great stuff, but it does burn like crazy!  Trust me when I tell you this!!

After cleaning everything, and installing new hoses as needed, reinstall the vacuum pump and/or the vacuum generator and the electrical wires.  Put it all back in the reverse order you took it out.  You do remember that don’t you?

Only after you have inspected every part of the operation…  from sanitary sewer pipes reconnected – both input and output, and electrical wires reconnected – be sure you get them right, only then do you go up and flip the breaker switches on to see if the units work.   Have someone (I don’t know why my wife refused to do this part, after all I had already done the hard part! – **) down in the crawlspace to check for leaks and run one or two water flushes to make sure everything is back on line.  If you have a small air leak, just switch the breaker switches off after the vacuum pump has cycled to prevent it cycling every so often.  Just remember to switch it back on before flushing the heads/toilets.  

If anyone else wants advice on how to work on their vacuflush head system, you can call me anytime and I will be glad to offer any advice….   like you’d be better off to get an expert to do it, or have your wife read the above and get her to do it, or call your best buddy and tell them they have to experience this wonderful opportunity to do something really different.  But don’t ask me to do it for you.  

** this reminds me of that old saying, “The flogging will continue until moral improves.)