Moving sewage outlet?

[Stefrobrts]

The black tank outlet on our trailer is located directly under the toilet, putting it about two feet under the trailer, pointing straight down. When it's time to hook up to it, you almost have to get on your knees to reach it, which is not a pleasant idea at most dump stations. Seems like I've seen new trailers with connections on the side of the trailer, where it would be much easier to hook up to. Has anyone rerouted or redirected their vintage outlet to make it easier to access?

[markdoane]

If you are taking off the belly pan, you can install a tee, with a macerator pump mounted on the side of the tee. It is easy to run 3/4" line from the macerator pump out to the side, and not have a lot of stuff hanging down. You would need a 12v power line to run the pump.

[malconium]

Stephanie,

I am intending to add a macerator pump to my AS (when I finally get to that point). It will need to mount below the belly pan with the way that my holding tank works. There is a unit available at the RV Parts Outlet store in Tualatin, OR for $152.95 that has my attention. In your case you could just install an elbow onto the bottom of your holding tank and mount the macerator horizontally. It would hang done slightly more than 3" total. The small hose would connect to the side of the pump and could easily be routed to any convenient place. It would also be a lot easiet to connect at the campsite than the 3" line if you wanted to do it then.

https://www.rvpartsoutlet.com/newsto...2FFF6A2A68EB32
Malcolm

[till]

Stephanie,

I plan on doing the same thing. You may have to cut a hole in the frame to route it out though. That is part of my master plan. Basicly just mount a 90 on the dump valve and a short section of pipe that goes through that frame with the proper cap and connector for dumping.

[Stefrobrts]

Since this is our first RV, macerator pumps are a new topic to me. I'll have to read up on them a bit. I assume you can still use the 3 inch hose, since that seems to be the size all the campground hookups are set up for? Does it slow down dumping a lot? In our system grey water runs out through the 3 inch hose while at the campsite (no grey tank, though I'd like to fix that someday to make boondocking a little simpler), is that a problem if I add one of these pumps?

[markdoane]

The advantage of a macerator pump is that you can use a 3/4" hose (just stick it down the hole) instead of dragging around a 3" hose. Also, it can pump uphill if that is required. You could also attach the 3/4" hose to an adapter on your 3" greywater hose, if you want to leave the 3" graywater hose hooked up to the campground hookup. There are really a lot of options how to use it.

If you decide to do this, I would use a tee mounted vertically on your tank outlet, with a regular valve and 3" cap pointed down, and the macerator pump mounted on the side outlet of the tee. That way you have a way to empty the tank if the pump malfunctions.

I mounted a new greywater tank forward of the axle, with a 3" outlet. By using a macerator pump, I was able to co-locate the macerator pump outlet with the grey tank outlet, just forward of the streetside wheelwell.

[eubank]

Ya know, my dad installed a swimming pool vacuum hose instead of an RV hose to dump his rig (a 5th wheel). He just makes sure that he uses a liquifying-type chemical in the black tank.

Lynn

[Janets Husband]

I have a few questions about macerator pumps and the wisdom of using them.
What do you do when the pump does not grind the gunk?
How long will one last, without repairs or cleaning?
What is the recommended maintenace?
I for one really like simple, and Gravity works without maintenance.
The dump valves are common to both systems so I won't consider them as an extra point of failure.

[87MH]

Originally Posted by Janet's Husband

What do you do when the pump does not grind the gunk?.

I tee'ed into the line between the dump valves and the discharge outlet (see White 3" tee below). If the Macerator fails, use the original dump system as prior to Macerator installation. - the only change to the original system is the installation of the 3 X 3 X 1 1/2 tee. I have not yet had it fail to pump, and it has had some pretty serious "loads" through it. I always pump the black tank first, allowing the gray water to "flush" the pump. - I would suppose that if a huge amount of solids were to hang up at the pump the head of grey water would tend to dilute them.

Originally Posted by Janet's Husband

How long will one last, without repairs or cleaning?.

I have a friend who has had one installed on his boat for 5 years (salt water application) and is still in service.

Originally Posted by Janet's Husband

What is the recommended maintenace?.

I don't recall that any service was recommended - there is a replacable rubber impeller - note that due to the impeller the pump will not allow water to "free flow" through the pump. The motor has to be running for any appreciable amount of fluid to pass.

Originally Posted by Janet's Husband

I for one really like simple, and Gravity works without maintenance..

Yeah, but the Macerator pump makes things SO EASY - and clean too. - One of the best mods I installed on the MoHo. It dumps quicker, easier to clean up (I have half unions on all connections), and NO chance of a 3" hose slipping off - yuck.

Originally Posted by Janet's Husband

The dump valves are common to both systems so I won't consider them as an extra point of failure.

IF you have to service a kump valve, install the Tee with the 1 1/2" leg plugged off. You never know when you will "warm up" to the idea of a Macerator.

Below are pics of the 12 gpm Jabsco pump installed on the 345.

[malconium]

I had been thinking that I would need to install my macerator pump below the belly pan because the new combined grey/black tank I intend to install will hang down below the belly pan by about 4". I was trying to get the pump as close to the bottom of the tank as possible. What suddenly occurred to me was that maybe the pump does not need to be as low as possible - just the pick up point. That got me to thinking about how I could mount the pump inside of the belly pan again.

So here is a proposal that I would like some feedback on...

1.) I would mount the pump inside of the belly pan and centered between the belly pan and floor.

2.) I would create some sort of elbow shaped 3" pipe that I would try to insert inside of the new tank. One end would connect to the side of the tank toward the macerator pump and the other end would rest on the bottom of the tank. I realize this would reduce the volume of the tank some but I am OK with that I think.

3.) I would cut away most of the bottom end of the elbow leaving small feet to support it a constant distance away from the bottom of the tank. I am thinking that the openings would be about 1" tall from the bottom of the tank.

4.) I would connect the macerator pump to the elbow from outside of the tank. My connection would pass through one of the holes in the cross-member that would be between the pump and the tank.

So does a macerator pump have enough suction to be able to work in a position where it is centered at a point maybe 6" above the floor of the tank?

What do you think?

Malcolm

[87MH]

Originally Posted by malconium

So does a macerator pump have enough suction to be able to work in a position where it is centered at a point maybe 6" above the floor of the tank? What do you think?

The Jabsco Macerator is "supposed" to be self priming to four feet ....however......while your pump mount description above should be fine for a gray water tank, I would think that the pump would have a difficult time picking up any solids at all through the 3" ell (no velocity in a 3" line to "lift" the solids). Remember the solids (both the toilet paper and the "other" stuff) must flow as a plastic until they hit the macerator blades where they are ground up into little bitty pieces that are then held in a suspension in the water and can be "pumped" like water. Also, as you indicated, when the water level in the tank is drawn down to the top of the cutout in your 3" ell , suction to the pump will be lost (air will be drawn into the pump) and the bottom 1 inch of fluid in the tank will not be able to be pumped out.

The description of your proposed combination gray/black tank plumbing sounds more like a true septic tank than a holding tank. I would be afraid that the solids would take quite a while to dissolve naturally (via biodegradation) to the point that they could be held in suspension and be pumped (pulled up with the water through the low velocity suction line), also I think that the cut outs (inlets) in the 3" ell would be low velocity choke points to the inlet of the pump, and would have a high likelihood of "packing off" with the "plastic solids".

So, in my opinion, I would have to say that your proposed plumbing arrangement would have a high likely hood of operational failure due to loss of suction or solids packing off somewhere in the suction line.

I might offer this as an alternate proposal...the bottom of the tank has already been established as the "low point" of the installation...install a 3" line horizontally into the tank where you want to dump from (a conventional 3" dump arrangement), install your valve onto this line, and install plumbing similar to my set up as pictured above (3" X 3" X 1 1/2" Tee). If the pump fails for any reason I have the conventional dump system as a back up. By taking the suction to the macerator from the downward facing leg of the tee the pump suction is assured of being flooded at all times (it will "suck" the tank dry). If you will note in my installation, the sections of the plumbing that are closest to the road, and subject to collateral damage, are all rubber or flexible PVC hose - the thinking was that these are sacrificial connections - easily reattachable or replaceable if damaged. One thing I should change if I have to work on the pump - the outlet of the pump in the last picture above is pointed "down" toward the road....the pump head is "clockable" in 90 degree increments - I believe if I turn the outlet 90 degrees (horizontal instead of vertical) it would be exposed to fewer road hazards.

In over a year of use (and over some really nasty gravel roads in Missouri) everything is still secure.

Good luck - I'm looking forward to pictures of your solution.

[74Argosy24MH]

Originally Posted by Janet's Husband

What do you do when the pump does not grind the gunk?
How long will one last, without repairs or cleaning?
What is the recommended maintenace?

Go to Phred's site, way down near the the bottom of the page is a diagram for hookup and the maintenance requirements.

He shows a bypass system in case of problems. He also says they do plug and need to be torn down yearly to be cleaned and to prevent damage. I read this a few years ago and also decided gravity works. You are still handling a sewer hose, but you are adding another item to maintain and a nasty one at that.

John

[Stefrobrts]

Dennis, your sig seems all the more appropriate considering the topic...

[malconium]

Dennis,

I appreciate your comments and suggestions. I had originally been thinking of an arrangement similar to what is in the attached sketch - except without the T between the macerator and the dump valve. Does this seem like a better overall approach? I notice that your assembly uses a 1-1/2" connection to the macerator. Do you think there is any advantage one way or the other for 1-1/2" vs 3"? The standard macerator pump I am looking at comes with the 3" connection and the pump body itself is pretty much the same diameter. Perhaps this approach would still not put the pickup point for the "plastics" low enough. What do you think?

Part of the reasoning for using a combined gray/black tank was that the extra water would help keep the solids in suspension and might help break them up better. Again what do you think?

Malcolm

[87MH]

Originally Posted by malconium

......I had originally been thinking of an arrangement similar to what is in the attached sketch - except without the T between the macerator and the dump valve. Does this seem like a better overall approach?

Personally, I think it is, because the "extra" Tee connection could either be used as a conventional dump, or, as I have done, install a water hose inlet with a valve to both wash the tank and provide "extra" water for the macerator pump....BTW, I have never had a problem with the pump grinding up anything I have thrown at it....had never had a water hose hooked up to the valve. I had read "Phred's" site previously - I do not see the requirement for the isolation valves he had before and after the macerator pump - the main tank valves should suffice to permit pump repair/maintenance....

I have never pulled the pump for maintenance - nor do I intend to - it might last 10 years or more - I prefer to take my chances with it lasting....bear in mind, the climate here in Houston is such that I do not winterize - if a really cold spell were to be on the horizon I would throw a bit of antifreeze at it, and I keep a small electric heater in the cabin set to the lowest setting.

Originally Posted by malconium

......I notice that your assembly uses a 1-1/2" connection to the macerator. Do you think there is any advantage one way or the other for 1-1/2" vs 3"?

The Jabsco I purchased had a 1 1/2" inlet - it was a heck of a lot easier to run the 1-1/2" instead of the 3" - plus, with the head of water from the gray water tank, I feel as is if I have a pretty good chance of pushing a "plastic slug" through the 1 1/2" line without too much difficulty. The downside of a 3" suction is possibly loosing the pump suction with a couple of inches of water left in the tank -- read below.

Originally Posted by malconium

......The standard macerator pump I am looking at comes with the 3" connection and the pump body itself is pretty much the same diameter. Perhaps this approach would still not put the pickup point for the "plastics" low enough. What do you think?

More than eliminating the solids, I would worry that it would loose suction and not pump all of the water out of the tank - giving credence to John's (74Argosy24MH) comments above - gravity works. For my particular setup, the installation of the macerator pump was absolutely the best thing to do - easy to set up, store, and cleanup the 1 1/2 inch discharge hose and with half unions at each termination everything gets buttoned up in seconds after pumping the "load". I used 1 1/2 inch hose (the pump outlet is 1") because I found a very sturdy PVC flexible hose that would not collapse and was "slick" on the inside - with the 1 1/2" hose I eliminated a lot of discharge head, allowing the pump to evacuate the tanks faster, and allowing for additional sections of 1" or 1 1/2" hose should I find that I would have to pump a good distance to get to a disposal inlet (with 1 1/2" discharge hose I am certain that I could pump at least 100’ into a toilet or similar disposal point).

Originally Posted by malconium

......
Part of the reasoning for using a combined gray/black tank was that the extra water would help keep the solids in suspension and might help break them up better. Again what do you think?

Since you asked....I do not like the idea of a single combined tank at all.....too much chance of odors and other "stuff" backing up into the sink or shower drains (especially the shower)...
Typically the solids do not stay in a holding tank long enough for the aerobic/anaerobic process to do much good as far as suspending the solids....I think that after a weekend of camping the bottom of the black water tank looks pretty much as the bottom of the toilet after the typical male takes a dump - only that it contains a heck of a lot more volume of everything. By “rocking” my black and gray water tank (pumping the black tank, equalizing the gray with the black, pumping the black again, equalizing again, pumping the black one more time, equalizing one last time, and pumping the gray dry) I feel as if I am getting the black tank as clean as possible without having wash jets installed in it. By leaving a few gallons of the gray water in the black water tank I think I leave enough pure fluid to help dilute the “plastics” as soon as they hit the tank, hopefully eliminating the dreaded “brown mountain” that I have personally witnessed, fought and ultimately was victorious over – but at a personal cost.
Another reason for keeping the two water systems separated, IF, at the end of a long weekend, someone really needs to take a shower and the tank(s) are nearly full, with two tanks I can do one of two things – transfer a bit of the gray water to the black tank, or drain a couple of gallons of the gray tank on the ground (or blue tank) so you don’t have to break camp prematurely – I’m not advocating surface disposal of gray water, but in some instances it is still acceptable.
I REALLY do not like to mess with a blue boy with the contents of a black tank in it.
Like I said, the installation of a macerator pump certainly worked for me, but each individual has to analyze their own circumstances.

[malconium]

It occurs to me that maybe I should design a mount for the macerator pump that could pivot downward when it was time to run the pump. I could picture using flexible rubber tubing between the tank and the pump that would bend downward when I lower the pump. The pivot point of the framework could be near the tank. This way the pump could be stored relatively high and used in a position that was definitely below the bottom of the tank so that gravity would help.

Another alternative might be to use a detachable macerator pump. Take a look at the following item:

https://www.rvpartsoutlet.com/newsto...EE151898627E89

This pump looks like it would mount pointing downward so it would definitely be helped by gravity. I think I still like the idea of having the pump permanently attached.

By the way I am intending to use a 1 way valve between the grey/black tank and the shower to prevent reverse flow. The idea to do so came from these forums and it seems like a good one.

Right now I guess I need to hurry up and get the rest of my floor replaced so that I can begin to zero in on the rest of the stuff.

Malcolm