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Macerator toilet system to replace entire vacuflush system

I am starting research into replacing the entire vacuflush system in basement and the Dometic/Sealand Magnum Opus model 3048 toilet with a macerator toilet.

 If I do the changeover it will either be this fall, or next year or two.  Our vacuflush basement mounted pump system and toilet are both working fine right now, so no hurry.  Quite a bit of noise with the vaccuflush, both from the toilet and from the pump in the basement.  Macerator would be quieter, and replace a aging system before it eventually has some type of failure.

Initial research shows a Dometic Masterflush 8700 series macerator toilet has nearly the same footprint (which is what we want), requires 20 amp service  and 12 gauge 12 volt wire.  Our current toilet has 12 gauge wiring to it, even though the vaccuflush toilet only requires 14 gauge and 7-8 amp fusing.

So the wiring is sufficent, but I need to check the fusing or breaker that serves the 12 gauge wiring and toilet.

We have a hamper behind the toilet with a false floor, so pretty good access to wiring and piping.  Under the bath sink in the counter, there is room for changing out vacuflush monitor to either a status panel for a macerator toilet with flush handle, or a remote flush controller for a macerator toilet without flush handle.

The remaining thing to determine inside the bathroom is the size of the discharge piping and water input piping size, to see if it will work as is or must be modified.  Also location of discharge and input pipes to macerator toilet (should be close).

In a bit I will discuss the basement vaccuflush pump system and piping that will have to be changed or modified.

Current system in diagram.

Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #1 –
I can see the following additional advantages to the swap out:

No more duckbills to replace every 3 years (I would guess the macerator system doesn't use them)

RV service folks are MUCH more familiar with macerator toilets (at least one toilet in every bath and a half DP is a macerator model) than VacuFlush systems.

ETA the one downside is you'll use more water/fill the black tank faster with a macerator toilet.  Just something to consider if you boondock or frequently do W/E-only sites.
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: Macerator toilet system to replace entire vacuflush system

Reply #2 –
Quote from: Michelle –
I can see the following additional advantages to the swap out:

No more duckbills to replace every 3 years (I would guess the macerator system doesn't use them)

RV service folks are MUCH more familiar with macerator toilets (at least one toilet in every bath and a half DP is a macerator model) than VacuFlush systems.

ETA the one downside is you'll use more water/fill the black tank faster with a macerator toilet.  Just something to consider if you boondock or frequently do W/E-only sites.
I've been rebuilding the vacuflush generator every 2 years (and sometimes sooner) when in a stable location, to prevent issues when traveling.  I replace duckbills and bellows as well.  With 2 of us full timing, there is a lot of usage. 

Dometic Masterflush 8700 series macerator toilet has a water reducing usage feature that allow the toilet not refilling water after flushing (mainly for boaters in heavy waves).  It will still use more water than vacuflush, but less than normal mode. 

Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #3 –
Pics of inside layout.  The fan control will have to move up, to make room for macerator status display or flush contoller.  Easy access for wiring.

The toilet and hamper are on outside wall, drivers side.

Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #4 –
Dan, where are your grey and black tanks located in your coach?  Just wondering why FOT set up this type in your coach!
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Macerator toilet system to replace entire vacuflush system

Reply #5 –
Basement
Quote from: juicesqueezer –
Dan, where are your grey and black tanks located in your coach?  Just wondering why FOT set up this type in your coach!

Not a direct drop.  Hard to visualize inside the coach, but seems black tank is further back than toilet.  Plumbing runs are mostly hidden.

Black and grey are behind rearmost basement door, by the water manifold when viewed from passenger side, and behind drivers side rear dump valves.  40' tag axle coach.

Toilet discharges to rear of toilet, not downward.

I'll post some pics of basement plumbing when I can get file types to work.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #6 –
In the pic of basement vacuflush generator, the black pipe from the vacuflush is the one that dumps into the black tank.

The white flexible one is the one feeding from the toilet.  Above the black and grey tanks the white flexible hose connects to black rigid piping. 
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #7 –
Quote from: AC7880 –
In the pic of basement vacuflush generator, the black pipe from the vacuflush is the one that dumps into the black tank.

The white flexible one is the one feeding from the toilet.  Above the black and grey tanks the white flexible hose connects to black rigid piping. 
There is little space and little access above the sewage  tanks (behind the water manifold cover) to merge the two black rigid pipes (feed and discharge). 

Seems easiest to retain the white flexible hose and modify the black dump pipe above the vacum generator to make a turn and then attach flexible hose to it.  I would hire a plumber to make that change.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #8 –
Quote from: juicesqueezer –
Dan, where are your grey and black tanks located in your coach?  Just wondering why FOT set up this type in your coach!


6106 is a custom floorplan.  It's a little AGDS, a little PBDS, and a little WTFS...  The couple who designed it did an amazing job IMHO.

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: Macerator toilet system to replace entire vacuflush system

Reply #9 –
More investigation on possibly installing Macerator  8700 series Masterflush toilet and removing vacu flush toilet and the vacum generator in the basement.

Both toilets use a 1/2" npt fresh water feed from the rear.  Both use a 1.5" discharge to the rear.  Current vacuflush has 12 gauge wiring which the masterflush requires.  And in the basment, that 12 gauge feed already has 20 amp breaker.  So that makes things simpler all around.

I'm suprised Foretravel used a 20 amp and a 12 gauge wire as the vacuflush requires only 8 amps, but it sure makes the feasibility easier.

Next thing to figure out is the black tank full monitoring that shuts down the vacuflush when tank is full.  The macerator toilet also has recommended (but optional) full tank monitoring/auto shutdown. 

What are the odds the full tank system on the Masterflush will be compatible with existing wiring/sensor?  (probably low).

Tecma macerator toilets need 8 to 10 gauge wiring (depending on length of wiring run)  and 40 amp at 12 volt.  That is why I am not looking at Tecma.

Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #10 –
Drawback as Michelle pointed out is water useage.

 Vacuflush uses .27 gallon in normal mode, and .08 in low mode.

Masterflush use .85 gal normal, .45 gallon low mode.

We rarely dry camp these days, but do use some campgrounds with no sewer drop on site, but with a dump station.

If wanting spare Masterflush parts on hand in case of issues:
 macerator motor $413 to $489
water valve $41 to $106
control module $apprx $706

Expensive to have variety of spares on board.



Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #11 –
If I do this in stages, and do the macerator toilet inside the bathroom first, I wonder if the vacum generator in the basement would work in combination with the macerator toilet with no issues?

Then I could schedule a plumber for the piping change in the basement a week or two later.  I can easily remove the vacumn generator (pump) myself, but need a pro for the piping modification.

We are full timers and can only have the toilet system down during daylight hours only and only one day at a time.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #12 –
Updates?
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Macerator toilet system to replace entire vacuflush system

Reply #13 –
Too bad these Coach manufacturers have to make flushing a commode complicated. Our Prevost had the Headhunter system. Uses a ton of water and extra plumbing to route everything from toilet to black tank. If black tank was a direct drop, I would have put in a Dometic 320 - like we did in the Foretravel- which is a direct drop to the black. All manual- no electricity required.

Re: Macerator toilet system to replace entire vacuflush system

Reply #14 –
Quote from: Peter –
Updates?

Project on hold other than investigating how to potentially do it.  Other items (relocating our home base) have taken priority. Our homebase now is a Escapees co-op in Sutherlin Oregon, new homebase will be a Escapees co-op in Benson AZ.

 Also changing hydraulic engine cooling fans from electronic control to wax control is being considered, and higher priority if I proceed on it. 

I have a complete rebuild kit on hand I bought last year for the basement vacumn system, so I can rebuild in the interim if necessary.  I may do that in the next month or two to buy more time for potential conversion t macerator toilet.

My son in law in OK is a licensed plumber. I will have him take a look at plumbing routing in the basement sometime this fall.  Not asking him to do the work, just give advice. 

Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #15 –
Quote from: erniee –
If black tank was a direct drop, I would have put in a Dometic 320 - like we did in the Foretravel- which is a direct drop to the black. All manual- no electricity required.

I would do the same if direct drop.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #16 –
Dan, I changed the 01 U320 to the wax control and it worked fine.  My engine temp was usually 186 F  with a high of 195 powering up rolling hills and then back down to 186.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Macerator toilet system to replace entire vacuflush system

Reply #17 –
Dan, I would not be too concerned with water issues with the macerator system.  We have installed a bidet in our coach and water usage is pretty high with this one, since it cleans itself before use and after.  Not an issue for us, remember, water is your friend when it comes to black tanks and issues.  Right now, I don't dump any more than before and we sometimes boondock or in a park with only W/E, plus we use the washer/dryer at least 3 times a week.  Having done plumbing work over the years, not licensed, but not afraid to take on just about anything with regards to plumbing, I went in and completely changed out my wet bay configuration on how FOT did theirs.  Works so much better!
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Macerator toilet system to replace entire vacuflush system

Reply #18 –
Juicesqueezer
Do you have pics of your wet bay alterations?
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Macerator toilet system to replace entire vacuflush system

Reply #19 –
Quote from: Peter –
Juicesqueezer
Do you have pics of your wet bay alterations?

I thought I had posted them once, but now have deleted those pics and I'm not tearing into the cover again to expose the inside.  Needless to say, I got tired of repairing the cables to the black and grey tanks and the weird setup with the 90's coming from those tanks, so went in and cut them all out and did a direct shot from black and grey out to the front of the bay.  I now have two gate valves out front and when I want to dump them both, I have a Y connector to allow this.  Not a difficult work around, but not for the faint of heart when it comes to doing the first cut!  Hope this helps!
Joe & Dottie Allen
Sold!  December 2023.      2000 U320; build # 5645
Our coach " Maxine"
Motorcade #  15922;  Escapee 150950; FMCA F330833; Boondockers Welcome;  Harvest Hosts;  Thousand Trails
'98 U320 from 2000-'06
USAF '62-'66

"Do not spoil what you have by desiring what you have not; remember that what you now have was once among the things you only hoped for." ―Epicurus

Re: Macerator toilet system to replace entire vacuflush system

Reply #20 –

I am beginning to once again research and plan for a macerator toilet  to replace both the Sealand opus magnum 3048 toilet and the vacumn generator in the basement.  Would like to get it accomplished between Jan and July at the latest. Have funds in place for toilet and pumber labor where needed.

For anyone who has had the Opus up (removed), does the tile go quite far under the toilet? The Opus is a 4 bolt mount, and the replacement macerator toilet 2 bolt mount. I will need to research drilling the tile for the new mount holes without breaking tile if it extends under.  Both toilets use 1/2" fresh water feed, 1.5" back discharge.

The replacement toilet will be a Dometic Masterflush 8740  white (bone not readily available), with flush handle, not remote flush panel. The foot print is VERY close in all dimensions to the exsisting. Have not picked the source yet.

12 gauge wiring is present from existing, and 20 amp breaker in basement serving the toilet/12 gauge.

As part of the basement mod, I just ordered: https://www.amazon.com/gp/product/B0CSN272RW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 
The existing grommet is hardened from age.

I have not yet figured out the basement pumbling mod to remove the vacumn generator. Pretty sure I will hire a pumber for it.

Any opinions on wheter or not the Macerator and vac generator would work together, if I do toilet first then vac generator removal?  (i think it would).




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Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #21 –
Quote from: AC7880 –
Any opinions on whether or not the Macerator and vac generator would work together, if I do toilet first then vac generator removal?  (i think it would).

I'd reach out to a marine service vendor with this question, especially someone like Environmental Marine.  Dometic/Sealand is unlikely to respond given they are more B2B.  I'm not sure if you can interface the vacuum generator's vacuum sense if a macerator toilet didn't provide it, plus the macerator toilet pushes from the toilet outlet and expects minimal resistance, where the vacuum generator pulls and needs to have a good seal in the toilet to pull vacuum against.  The two would need to be coordinated or the plumbing in between would either contain pressurized waste OR the vacuum generator pump would run indefinitely.
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: Macerator toilet system to replace entire vacuflush system

Reply #22 –
Also, a residential plumber won't have a clue about VacuFlush or macerator toilets.  You'll want an RV or marine tech familiar with both systems.

You might want to ask the conversion question on a Winnebago board.  I recall from reading iRV2 that a fair number of WGO floor plans use VacuFlush toilet systems.
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: Macerator toilet system to replace entire vacuflush system

Reply #23 –

Going ahead with this project (as long as the source I ordered the macerator toilet from today (weekend) actually does have it in stock). (they did).

Dometic MasterFlush 8700 Macerating Toilets for Boats and RVs 

The replacement toilet will be a Dometic Masterflush 8740  white (bone not available), with flush handle, not remote flush panel.

Pieces parts for plumbing in the bay:
Amazon.com: Calvana 2-Pack 1-1/2" RV Rubber Grommet (12483), RV Water Tank... (old one is hardened, will remove abs pipe for cut and gluing).  Edit: I did not use this. Too hard working in mainly blocked 5" space above black tank. Used plumbers silicone grease on old original gasket.

90 degreee turn 1.5", with proper connector for the white sanitation hose in pic:  90 degree Bend Kit, 1.5" - Marine Sanitation & Supply One end transition cement to black ABS, other end into sanitation 1.5" hose .  Edit: did not use the 90. Did use the smaller adapter hose conversion piece.  Used  in ABS 180 degree into the 1.5" sanitatation hose.

In the plumbing pic, the black ABS will be cut back, the 90 degree cemented (chemical welded) on, white hose attached.  I can easily support it over the black tank at the transition to open space.  Not enough room to work over the black tank to make transitions there, though I may give it a shot. Edit - used a abs 180 degree from home depot instead.

I will have toilet  up and running first, with white bay sanitation hose into a bucket to make sure it works(water only) before I cut the piping and remove the vacum generator.

As mentioned above, there is 12 gauge wiring (hot and  ground) at the current toilet with 20 amp resettable breaker. I will add an additional blade 20 amp fuse at the control box for new toilet.  Already have 1/2 inch water supply and 1.5" discharge at current toilet. 

Edit: the only PVC actually used was the conversion small piece to 1.5" OD sanitation hose connecter.  The 90 PVC was not used.  Found a Home depot ABS 180 to use.

More pics above.


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Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Macerator toilet system to replace entire vacuflush system

Reply #24 –
Quote from: AC7880 –

In the plumbing pic, the black ABS will be cut back, the 90 degree cemented (chemical welded) on, white hose attached.

Black is ABS, white is PVC.  Waste plumbing is normally done with all ABS.  There is a special adhesive (transition) that you can use to join them IF it's a non-pressure situation (the two cannot be chemically welded together, so it's a weaker joint).  Not sure if the macerator pump in the toilet makes it a pressurized system, but I'd hate for you to find out after the fact that the use of PVC causes a problem.

In a regular building situation, it's against code to glue them.  You have to use a mechanical (no hub) coupler, but again I don't know if this is okay under pressure if it's created because of the macerator.

Here's a good explanation:  Connecting ABS To PVC Piping: What Do Home Inspectors Say?

I would strongly advise getting all ABS plumbing parts for this project.
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