Inline ball valve between holding tank and macerator

[Mick Laver]

For the second time in five years I've had the seal on my macerator fail and the most inopportune time - full tank and no pumpout in sight. It's pretty impossible to replace a macerator with a spare without making a huge mess while the tank's full, so I'm looking for a way to secure the line from the holding tank to the macerator. I'm thinking a merelon ball valve, or something equivalent that can resist sea water and other "stuff." I believe this has been discussed on the list before and even talked to Stu about a 2007 reference he'd made, but unfortunately I haven't been able to find the post. Can anyone help?

Thanks

- Mick

[KWKloeber]

PS: I have gotten a few excellent open-box buys on GF double-union valves on eBay.

Hey Mick

If you insert a ball valve be sure it's a full-port. 
For commercial uses that I have, I like Gorge Fisher valves and would use a compact GF+ 374 PVC-U, double true union, threaded socket (to accept hose barbs) valve.  Pricey is an understatement but the huge benefit is you can remove it to service/clean and not screw around with hose barbs. The 374 is a less expensive cousin of the GF+ 375 PVC-U which is what I used for severe applications.
https://www.gfps.com/content/dam/gfps/com/datasheets/en/gfps-datasheet-374-375-ball-valve-en.pdf

.

[scgunner]

Mick,

There's got to be a pump out station somewhere in San Diego, I'd find one even if it requires some motoring. Changing out a macerator pump even when the tank has been pumped out and flushed several times is not an enjoyable experience (don't ask me how I know!) Also I'd highly recommend wearing a respirator during the operation, gloves aren't a bad idea either. 

[Ron Hill]

Mick : I've looked at that idea for MANY years - there just is not enough space for any valve!!  Wish there was!!

A thought

[Noah]

I agree with Ron that on the MKI it is very tight. Maybe Mick's MKII has more room between macerator pump and tank?

[KWKloeber]

I agree with Ron that on the MKI it is very tight. Maybe Mick's MKII has more room between macerator pump and tank?

Noah - are you saying between the tank outlet and tee for the macerator?  Is there 5 inches?

[Noah]

Dang! I just left the boat or I would have measured and taken a photo.. but, to my recollection, the macerator is almost touching the tank with a short (maybe 3in.) hose connecting the two.

EDIT: here are some pics I took in 2018 when I installed new thru-hulls. While pics are not ideal,  they may give some idea of space there.

[KWKloeber]

Update.

Yeah Noah, I see a bulkhead or wall or something.
Looks like you have the  tank hose barb almost  butted against the barb on the macerator.

(all conjecture on thicknesses but) eliminating the width of the hub on the exit barb and cutting off the barb on the macerator, there's enough distance for a compact valve and still hold a square dance.

I love when I hear "must do" or "can't do" something (like install a water cooled riser in a 34.)  It gives me "engineer Plan B tingles." d;-)

Yeah dang.
Is that up against a bulkhead or is there some flexibility/leeway in position of the macerator?

[Jon W]

It is very tight. After the studs holding the pump/motor together corroded and fell apart, I replaced the studs with SST ones and relocated the macerator to move it higher and to get rid of the special 90 degree inlet to the pump to make replacement easier. I think the Shields sanitation hoses from the tank to the elbow, and from the elbow to the macerator are each 6-7" long. Theoretically I can replace the pump/motor with the holding tank 1/2-3/4 full without spillage. Haven't tried it, and hope I don't have to.

[KWKloeber]

Thx Jon.  Nice pix, very "explicative." 
The way you relocated it (very nice!) a valve would fit either on the horiz** or on the vertical. 

And leave room for two square dances.

**(On the horiz so long as you have 1-7/8" between the center of the tank outlet to the hull.)


-Ken

[Noah]

Jon's pump is Jabsco and mine is Shurflow, and I have perhaps more restrictive wiring routed in that direction? Who knows what Mick (original poster) has on his MKII?? When my pump goes, I should probably look into moving it a bit too. Hopefully, that day is way far off.

[KWKloeber]

I dint look up the measurements of the Jabsco (like mine) vs the Sherwood, but product pictures look like they are very close to the same.  Same form factor and inlet.

I won't beat this up any more but if anyone wants to install a ball valve (BEFORE their macerator fails and it becomes a poopy mess) I can show how to make it fit. 

[Mick Laver]

Hi all
I've attached a couple of pix. I measured about 14 inches from the macerator to the tank outlet, realistically only about a foot usable to put a valve in, and that on a pretty severe bend. It *might* be possible, especially using Raritan's SaniFlex which is a lot bendier than the Shields (see last pic). At this point I'll just add "check macerator" to the list of things I need to pay more attention to. When I pulled the macerator out the screws holding the "head" on were quite loose, telling me the thing had been failing for a while.

[KeelsonGraham]

We had the same problem recently. Full tank, failed macerator. Luckily, we hadn't used the tank for poopies, so we syphoned it into the bilge and then pumped out. No smell or unpleasantness. But I wouldn't do this for a poopy tank!!

[KWKloeber]

Gobs of room for a compact 1-1/2" valve, Mick.

"if anyone wants to install a ball valve ... I can show how