Macerator Installation

G

gene

New member
Sep 29, 1999
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And I like the rubber y that Duane uses instead

gene

>just a suggestion. There is an excellent installation procedure for a
>mascerator in the March 2000 issue of Motorhome marketplace by Dan Stuckey
>of the GMC Heritage Cruisers. It is excellent. I only would change one part
>of it.
>
>I would not glue anything together. I would cut off the dump valve about 3"
>forward of the original dump valve and attach the ABS 3" X 3" X 1 1/2" T
>with a 3 1/2" X 4" neoprene adapter available at any plumbing supply store.
>I would do the same with the output to the 3" dump pipe. That way if you
>ever have to repair anything it can be easily and quickly taken apart and
>repaired. An added advantage is the neoprene couplings act as a shock
>absorber to all the fittings.
>Jut a thought to make things less comlicated.
>

>>

>>> www.westmarine.com This is where we got the $99.00
>>> deal.
>>
>>The latest westmarine sale catalog has it at $110.00
>>until June 18.
>>
>>Jim
>>
>>75PB in MN
>>
>>__________________________________________________
>>Do You Yahoo!?
>>Yahoo! Photos -- now, 100 FREE prints!
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>>
>>
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
Last night I posted about a "little" spill that I had when removing the
macerator with what I thought was an empty black tank.

Here's what's going on:

The JABSCO has an inlet that is concentric with respect to the outer shell
of the macerator. The inlet opening is 1.5" while the shell is 3" in
diameter. That leaves about .75" above the bottom of the 3" opening left in
the tank when the tank appears empty to the macerator. I'm not certain of
how much of the impeller has to "see" liquid in order to pump, although I'm
getting a few ideas. It takes quite an increase in rear height to
compensate for the .75" of residual water left in the tank. FWIW, the tank
may end up with more than one inch of liquid left if my macerator's
operation is any guide to the problem.

Henry
 
>Last night I posted about a "little" spill that I had when removing
>the macerator with what I thought was an empty black tank.
>
>Here's what's going on:
>
>The JABSCO has an inlet that is concentric with respect to the outer
>shell of the macerator. The inlet opening is 1.5" while the shell is
>3" in diameter. That leaves about .75" above the bottom of the 3"
>opening left in the tank when the tank appears empty to the
>macerator. I'm not certain of how much of the impeller has to "see"
>liquid in order to pump, although I'm getting a few ideas. It takes
>quite an increase in rear height to compensate for the .75" of
>residual water left in the tank. FWIW, the tank may end up with more
>than one inch of liquid left if my macerator's operation is any
>guide to the problem.
>
>Henry

Henry - you can buy an offset adapter which goes into the three inch
opening and has a 1-1/2" outlet that is offset from the center. This
has a male 3" on one side and a male 1-1/2" on the other. I went to
look at the pictures on both Gene and Billy's sites and I think that
both of them are using an adapter with the 1-1/2" centered. This, of
course, will leave about .75" still in the tank.

I may have to crawl under my GMC to take a picture of my off centered
reducer. The are readily available at most RV parts stores. I
bought one at my local small RV store here in Santa Fe when I added
my maserator.

Emery Stora
77 Kingsley
Santa Fe, NM
 
>Henry - you can buy an offset adapter which goes into the three inch
>opening and has a 1-1/2" outlet that is offset from the center. This has
>a male 3" on one side and a male 1-1/2" on the other. I went to look at
>the pictures on both Gene and Billy's sites and I think that both of them
>are using an adapter with the 1-1/2" centered. This, of course, will
>leave about .75" still in the tank.

That's what I see. My macerator installation was done by a PO - actually
suspect that it was done by an RV shop given the materials etc.

Since I'm redoing the outlet anyway, I plan on looking for an offset
adapter. Of course, that also means getting a new macerator since the front
doesn't have a pipe inlet and I can't see any threads. BUT, I'll double
check. Maybe I'll plumb in an emergency dump as well.

Henry
 
>
>>Henry - you can buy an offset adapter which goes into the three
>>inch opening and has a 1-1/2" outlet that is offset from the
>>center. This has a male 3" on one side and a male 1-1/2" on the
>>other. I went to look at the pictures on both Gene and Billy's
>>sites and I think that both of them are using an adapter with the
>>1-1/2" centered. This, of course, will leave about .75" still in
>>the tank.
>
>That's what I see. My macerator installation was done by a PO -
>actually suspect that it was done by an RV shop given the materials
>etc.
>
>Since I'm redoing the outlet anyway, I plan on looking for an offset
>adapter. Of course, that also means getting a new macerator since
>the front doesn't have a pipe inlet and I can't see any threads.
>BUT, I'll double check. Maybe I'll plumb in an emergency dump as
>well.
>
>Henry

Henry - don't think you would need a new macerator because the
adapter is not pipe but it is abs plastic. You can just use a rubber
coupler from the adapter to the front of the macerator. I'll try to
get a picture of mine and post it in the next day or two.

Emery
 
If you read Duane's description, he just builds up the outside of the
Macerator a little and it fits the adaptors , so you should not have to buy
a new pump...

gene

>
>>Henry - you can buy an offset adapter which goes into the three inch
>>opening and has a 1-1/2" outlet that is offset from the center. This has
>>a male 3" on one side and a male 1-1/2" on the other. I went to look at
>>the pictures on both Gene and Billy's sites and I think that both of them
>>are using an adapter with the 1-1/2" centered. This, of course, will
>>leave about .75" still in the tank.
>
>That's what I see. My macerator installation was done by a PO - actually
>suspect that it was done by an RV shop given the materials etc.
>
>Since I'm redoing the outlet anyway, I plan on looking for an offset
>adapter. Of course, that also means getting a new macerator since the front
>doesn't have a pipe inlet and I can't see any threads. BUT, I'll double
>check. Maybe I'll plumb in an emergency dump as well.
>
>Henry
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
>Hope this helps everyone thinking of installing a mascerator. This
>installation is easy using the flexible plumbing sleeves and relatively
>cheap. The big advantage is no 1" radiator hose coming out the back to play
>with.
>
>tom

Sounds like a great method for handling this messy problem. Thanks for a
very clear description of it.

Regards,
Steve in N. Texas
 
The first 2 photo's at:
http://www.web-access.net/~bmassey/macerator/index.html
show what was labeled as a "Holding Tank Bushing" at the small RV Supply
store here. It is PVC and is glued into the 3" tee. The 1 1/2" fitting is
female and is offset to the bottom of the bushing. I also tilted the tee
down just a little to allow for better drainage.

I haven't had to take the system apart since it's installation, so am not
sure how much fluid it leaves in the tank. Seems to work well
though. It's dern sure a lot easier to work with than the original setup.

hth
bdub

>>Last night I posted about a "little" spill that I had when removing the
>>macerator with what I thought was an empty black tank.
>>
>>Here's what's going on:
>>
>>The JABSCO has an inlet that is concentric with respect to the outer
>>shell of the macerator. The inlet opening is 1.5" while the shell is 3"
>>in diameter. That leaves about .75" above the bottom of the 3" opening
>>left in the tank when the tank appears empty to the macerator. I'm not
>>certain of how much of the impeller has to "see" liquid in order to pump,
>>although I'm getting a few ideas. It takes quite an increase in rear
>>height to compensate for the .75" of residual water left in the tank.
>>FWIW, the tank may end up with more than one inch of liquid left if my
>>macerator's operation is any guide to the problem.
>>
>>Henry
>
>Henry - you can buy an offset adapter which goes into the three inch
>opening and has a 1-1/2" outlet that is offset from the center. This has
>a male 3" on one side and a male 1-1/2" on the other. I went to look at
>the pictures on both Gene and Billy's sites and I think that both of them
>are using an adapter with the 1-1/2" centered. This, of course, will
>leave about .75" still in the tank.
>
>I may have to crawl under my GMC to take a picture of my off centered
>reducer. The are readily available at most RV parts stores. I bought one
>at my local small RV store here in Santa Fe when I added my maserator.
>
>Emery Stora
>77 Kingsley
>Santa Fe, NM
 
My "revision" from initial install might be of interest :-)

http://www.my-gmc.com/macerato.htm
May 30,1999: Redoing the Macerator installation

Sofar I havn't torn the macerator off. Not sure how much still remains in
the tank but at least it's less than before.

Still love it (the macerator).

Heinz

> Last night I posted about a "little" spill that I had when removing the
> macerator with what I thought was an empty black tank.
>
> Here's what's going on:
>
> The JABSCO has an inlet that is concentric with respect to the outer shell
> of the macerator. The inlet opening is 1.5" while the shell is 3" in
> diameter. That leaves about .75" above the bottom of the 3" opening left
in
> the tank when the tank appears empty to the macerator. I'm not certain of
> how much of the impeller has to "see" liquid in order to pump, although
I'm
> getting a few ideas. It takes quite an increase in rear height to
> compensate for the .75" of residual water left in the tank. FWIW, the tank
> may end up with more than one inch of liquid left if my macerator's
> operation is any guide to the problem.
>
> Henry
>
>
 
Henry & Guys
When I installed my macerator last fall I used an 3 X 1 1/2 eccentric reducer
which offsets the pump suction to the edge of the pipe, I also rotated
the piping
a little bit so the pump is the low point in the line and my tank
empties completely without problems. I have not yet received my new
digital camera yet but when I do I will post the installation.

J.R. Wright
GMC GreatLakers
77 Eleganza II
Michigan

>
> >Last night I posted about a "little" spill that I had when removing
> >the macerator with what I thought was an empty black tank.
> >
> >Here's what's going on:
> >
> >The JABSCO has an inlet that is concentric with respect to the outer
> >shell of the macerator. The inlet opening is 1.5" while the shell is
> >3" in diameter. That leaves about .75" above the bottom of the 3"
> >opening left in the tank when the tank appears empty to the
> >macerator. I'm not certain of how much of the impeller has to "see"
> >liquid in order to pump, although I'm getting a few ideas. It takes
> >quite an increase in rear height to compensate for the .75" of
> >residual water left in the tank. FWIW, the tank may end up with more
> >than one inch of liquid left if my macerator's operation is any
> >guide to the problem.
> >
> >Henry
>
> Henry - you can buy an offset adapter which goes into the three inch
> opening and has a 1-1/2" outlet that is offset from the center. This
> has a male 3" on one side and a male 1-1/2" on the other. I went to
> look at the pictures on both Gene and Billy's sites and I think that
> both of them are using an adapter with the 1-1/2" centered. This, of
> course, will leave about .75" still in the tank.
>
> I may have to crawl under my GMC to take a picture of my off centered
> reducer. The are readily available at most RV parts stores. I
> bought one at my local small RV store here in Santa Fe when I added
> my maserator.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM

- --
 
>Today when I go and work on my coach I will take digital pictures of my
>installation.

Thanks Tom.

>You start by cutting the current dump tube off about 5" from the dump tube
>which is about as close as you can cut it since the crossmember is so very
>close.

Unfortunately my plumbing was installed by a PO. Original dump tube is
history. The macerator attached directly to the slide valve via a rubber
coupler. AND, the slide valve leaks from the body.

>At the GMC Heritage Cruisers Rally in Watkins Glen this last weekend I had
>the good fortune of seeing another recent installation of another member and
>will now make one modification to this. A transition at a bulkhead connector
>mounted under the rear of the coach going to a 3/4" quick disconnect
>available from my local plumbing supply house.

That's what I've used on my macerator for the last two years - it's a big
help. No fussing with screw on connectors.

>Hope this helps everyone thinking of installing a mascerator.

Nice description.

Henry
 
>If you read Duane's description, he just builds up the outside of the
>Macerator a little and it fits the adaptors , so you should not have to buy
>a new pump...


My macerator pump does not have a pipe fitting of any kind. As far as I can
tell, it was designed to be directly plumbed into a system using a rubber
adapter. It makes sense when you look at the JABSCO plumbing diagram in
which the tank outlet is at the lowest point in the holding tank and the
pump is plumbed in such a fashion as to guarantee that the tank can be emptied.

Henry
 
yep he slides it over the outside of the pump near the grinder.

gene

>
>
>>If you read Duane's description, he just builds up the outside of the
>>Macerator a little and it fits the adaptors , so you should not have to buy
>>a new pump...
>
>
>My macerator pump does not have a pipe fitting of any kind. As far as I can
>tell, it was designed to be directly plumbed into a system using a rubber
>adapter. It makes sense when you look at the JABSCO plumbing diagram in
>which the tank outlet is at the lowest point in the holding tank and the
>pump is plumbed in such a fashion as to guarantee that the tank can be
emptied.
>
>Henry
>
>
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
I will be posting pictures of my installation soon on my
site also. I know my installation is unique because I made
the offset fitting 3" to 1 1/2". Yep thats me, work hard
not smart. BTW my tank drains all the way and the pump is
in the Generator compartment.

=====
Alan Bredbury
Clinton, Ct.
1974 GMC 26' Classic Motorhome
http://www.finesttool.com/index.html/special.htm

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