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Topic: Dometic Vacuum Toilet burps.  (Read 252 times) previous topic - next topic

Dometic Vacuum Toilet burps.

As the saying goes, it worked perfect on the last trip.  Wife told me I need to look at her toilet since after she flushed it burped and got her wet.  I checked and Gray/Black tank is empty, coach only has one tank that does both gray and black water.  Not sure what to do to start trouble shooting as to what is wrong with it. I remember reading somewhere about a duck bill and they can go bad. I have no idea where this is located in this coach or how to get to it. I could see if the duck bill is going bad it might not have the regular vacuum but not sure why it is spitting.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Dometic Vacuum Toilet burps.

Reply #1 –
After doing some research on the vf toilet I am not sure what kind it is. It looks nothing like the ones in the posts on Foreforums. There is no label on toilet unless I have to remove it to see the back.  The push button control says Dometic. In looking at pictures it might be a Dometic MasterFlush 8920.  I got a call into FOT to see if I can find out what model and if they have an idea where to start troubleshooting.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Dometic Vacuum Toilet burps.

Reply #2 –
The duckbills are in the pump plumbing of the vacuum generator in the basement.  They need to be replaced roughly every 3-4 years because the rubber hardens with age, etc.  They ensure the contents go towards the black tank - kind of like a check valve.  If they leak, you generally won't hold vacuum.

VacuFlush Pump Rebuild

The bowl seal also should be replaced at roughly the same interval, or if it starts leaking. 

Is she describing the water splashing up as the flush ball opens?  That could be the vacuum level a little too high as well.

I did find this potentially helpful discussion via Google which pointed to the above ball seal and vacuum level:
 VacuFlush Spitting Up - Trawler Forum
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Dometic Vacuum Toilet burps.

Reply #3 –
Quote from: turbojack –
As the saying goes, it worked perfect on the last trip.  Wife told me I need to look at her toilet since after she flushed it burped and got her wet.  I checked and Gray/Black tank is empty, coach only has one tank that does both gray and black water.  Not sure what to do to start trouble shooting as to what is wrong with it. I remember reading somewhere about a duck bill and they can go bad. I have no idea where this is located in this coach or how to get to it. I could see if the duck bill is going bad it might not have the regular vacuum but not sure why it is spitting.

You do have the vaccufush system versus a macerator? You have the vacum generator in the basement?

If so, and you replace the duck bills, I recommend you change the bellows (piston) at the same time. Very little extra labor beyond replacing only duck bills.

On our 2003 U320 parts and source follow.  Your parts are likely different part numbers.  Seacoast can help you order the correct parts.

Edit: on our coach 4 duckbills required, 2 kits. Yours is likely the same.

Dometic Sealand Vacuflush Bellows Kit
Dometic Sealand Vacuflush DuckBill Valves 1 1/2"
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Dometic Vacuum Toilet burps.

Reply #4 –
I have come to the conclusion that it is a Dometic MasterFlush model ??8500??. Not sure what the model number is.  It's a macerator toilet. It doesn't have a  flush ball. If there is something it is totally out of view.  It looks like it will be easy to  remove, 2 screws, unscrew water,  unplug electric, and loosen  1 hose clamp. 

Figuring out what broke my be a different story.  Going to wait until  I get home before I remove it.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago
 

Re: Dometic Vacuum Toilet burps.

Reply #5 –
Quote from: turbojack –
I have come to the conclusion that it is a Dometic MasterFlush model ??8500??. Not sure what the model number is.  It's a macerator toilet. It doesn't have a  flush ball. If there is something it is totally out of view.  It looks like it will be easy to  remove, 2 screws, unscrew water,  unplug electric, and loosen  1 hose clamp. 

Figuring out what broke my be a different story.  Going to wait until  I get home before I remove it.


There are some very good YouTube videos of troubleshooting and doing maint on macerator toilets.  Likely something was flushed that shouldn't have been wrapped on the impeller blades.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide