VACU FLUSH Problem

[Brian Nolf]

Hello Everyone,
   I'm a new guy to the forum. I Just purchase a 2000 Marquis 42 Amethyst. It has 2 toilets. In the rear bathroom is the vacu flush switch. When I turn the switch on, it goes red and then turns itself off. Now I have had a 2000 Searay 270 Sundancer and understand what the vacu flush theory is. Can anyone tell me where they have hidden the vacuum pump ?!!! Also if you know why it's shutting itself off that would help too....I don't hear any sound at all from the pump...  The front toilet works with gravity but the rear toilet does not want to drain well at all. I pray you guys can help me through this. In the boat it was easy to find cause it was back under the engine hatch.............. Obviously the motorhome is going to be a very steep learning curve.
Thanks in advance for your help !!

Brian Nolf

[Steve Huber Co-Admin]

Brian,
I'm pretty sure your coach is a 2001 as the Amethyst model didn't come into existence until the 2001 model year. See the Brochures to verify. It may have been built in late 2000 however as this was common practice.
Since the toilets are close together and approximately over the wet bay, I'd expect the pump to be in that bay.
Steve

[Fred Brooks]

    Brian,
There are a few things to consider, the vacuum pump is inside the tanks enclosure. Remove the curb side carpeted cover in the compartment forward of the drive axle. The 3 most popular faults are the tank is full and cancels the flush cycle or false reading from the tank sender. 2- The vacuum pump is inop or blown fuse, 3- The discharge pipe from the toilet to the tank is plugged. (Sometimes guests or children contribute). There are 3 videos on youtube that may assist. Hope this helps, Fred

[Steve Huber Co-Admin]

Fred,
Apparently there are different approaches depending on the model. The manual I looked at (500 plus, 706,and 1000 series) shows an external vacuum pump and tank in line between the toilet and waste tank.

Brian, what model are you toilets?
Steve

[Brian Nolf]

Not sure Steve. Need to dig into this. I'm just real confused the the switch turns itself off in 2 seconds. If it was a blocked line I would think the pump would try to pump a bit. The tank is totally empty. Oh, by the way Steve. This baby was built in DEC. 1999. Before Monaco bought them. I had a hell of a time finding a Brochure for this thing 

[Brian Nolf]

Hi Fred & Steve
  So like i said in my post. When you switch the switch on, It turns itself off in approx. 2 seconds. If the motor was burned out would it do that? If the fuse were blown, would the switch even light up ? If it was clogged wouldn't the pump try to cycle? And lastly. If it's the pressure switch would it act like that ? The tank is completely empty........

Thanks Fred & Steve !  Your help is priceless !!

Brian

[Steve Huber Co-Admin]

Brian,
There are a number of Vacu Flush manuals on the web but w/o your model# it is difficult to ID which one is applicable. Couple of thoughts... If the motor is jammed it may produce the symptom you are describing as it may take a few seconds for the amperage draw to become high enough. However, I'm surprised that a circuit breaker / fuse doesn't trip. Checking to see if there is 12v on one side of the switch when it shuts off will tell you if a breaker is dropping out or if the switch itself is bad. Your coach has thermal breakers in the front elec bay. If excessive current is drawn, they heat up and open. When they cool down they reset. However, the diagrams in Coach Assist don't ID a breaker for the toilet, but that's not surprising. If the switch fails and then won't work for a period of time, get it to fail and then check the breakers fed directly by the battery to see if any don't have 12v on their output.
Alternatively some Vacu Flush toilets have a service switch on the rear of the unit. If in the service position, the unit can exhibit the type of symptoms you are seeing.
Steve

[Brian Nolf]

Thanks Steve,
    When it stops pouring rain hear, I'll go dig through my paperwork and see if I can find a model # on this thing. I'll post when I'm positive . Thank You So Much !!

Brian

[Steve Huber Co-Admin]

There should be a label w/part # somewhere on the toilet, usually in the rear.
Steve

[Brian Nolf]

OK Steve,

   I found a VACUFLUSH owner's manual. Hand Written on the front is MODEL# 506  SERIAL# 0506003379. Is that what you and Fred were asking for

Brian

[Steve Huber Co-Admin]

Brian,
Here is the manual. I'll load it on Coach Assist also for future reference. It contains what appears to be a fairly comprehensive troubleshooting section.
Steve
https://www.dometic.com/assets/46/90/operating%20manual_64690.pdf