Failing macerator pumps

[crosswire]

My two cents ...

I have a standard manual Jabsco head with a Jabsco self-priming macerator and TP is allowed as long as it is not a wad the size of a baseball. I make that clear to all visitors to my boat. As a result, I have not had any problems with the waste machinery; however, I have had problems with clogged piping from the tank to the pump. The piping was installed with two 90 degree elbows and a three-way valve, good places for a clog. The clogging problem occurs only when the tank is left too long with waste in it. Pumping after each cruise with a seawater or freshwater flush seems to address that problem. The tank has a V shaped bottom with suction at the lowest part of the V, so the tank can be almost totally emptied. I run the pump until I hear air bubbling from the discharge seacock outside the boat and the pump noise changes. The pump on/off switch is hidden near the pump and valves. With the pump below the tank and waterline, I prefer to close the two valves after flushing the pump to minimize any leaks that may occur.

I have had two diaphram waste pumps in other boats: one was manual and required the v-berth cushions to be removed to access the pump handle, the other was electric and the pump rod broke after about 6 months use. No debris was found in the pump body.

[CaptTom]

Originally Posted by crosswire

...The piping was installed with two 90 degree elbows and a three-way valve, good places for a clog...

Good point. I try to avoid 3-way valves whenever possible. First, have the head pump directly to the tank. Use the macerator (or even gravity, if so configured) to empty the tank where it's legal to do so.

Assuming you already do that (we're talking about macerators, after all) then there's no reason to have a 3-way valve anywhere. Have another way to "lock out" the ability to discharge for when the Potty Police come knocking. For me it's a key switch for the macerator. The key is hidden, never left in the switch.

[s/v Jedi]

Again, the biggest problem many face is that their toilet doesn’t macerate. Most of the problems described would be prevented with a macerating toilet.

Second biggest problem is the choice of pump. Get the Whale Gulper waste pump. It does not get hair wound around the shaft, it can run dry without trouble, it will even pump air or any air/liquid/solids mix.

Third problem is scaling, smells etc. and these are largely avoided by using fresh water flush.

I do like schedule 40 PVC used for waste plumbing, but how do you easily go from pipe to hose? Those barbed adapters are of the devil imo.

[malbert73]

Originally Posted by s/v Jedi

Again, the biggest problem many face is that their toilet doesn’t macerate. Most of the problems described would be prevented with a macerating toilet.

Second biggest problem is the choice of pump. Get the Whale Gulper waste pump. It does not get hair wound around the shaft, it can run dry without trouble, it will even pump air or any air/liquid/solids mix.

Third problem is scaling, smells etc. and these are largely avoided by using fresh water flush.

I do like schedule 40 PVC used for waste plumbing, but how do you easily go from pipe to hose? Those barbed adapters are of the devil imo.

Agree on using PVC when possible. I found the PVC hose barbs and Saniflex hose are pretty easy to use together. That hose revolutionizes plumbing a sanitation system IMO

[crosswire]

Capt Tom, thanks for the reply. The 3 way valve is used instead of a tee at the tank; flow options are to macerator or dockside pump out. Once the tank is flushed and pumped out, the valve keeps waste out of the pump and the piping leading to it.

[Bowdrie]

Originally Posted by s/v Jedi

I do like schedule 40 PVC used for waste plumbing, but how do you easily go from pipe to hose?

Not to worry, all sorts of parts, many using the Dometic adaptor.
It glues into fittings and provides a great fit on hose without barbs.
A couple pages of parts.
https://marinesan.com/pvc-fittings/?page=1
https://marinesan.com/pvc-fittings/?page=2

[sinnerman]

Originally Posted by malbert73

Agree on using PVC when possible. I found the PVC hose barbs and Saniflex hose are pretty easy to use together. That hose revolutionizes plumbing a sanitation system IMO

On my boat's system I used PVC pipe and Saniflex hose with 1-1/2" hose fittings from Marine Sanitation. https://marinesan.com/pvc-fittings/.

Top of the line ABA hose clamps, utilizing 2 clamps per connection wherever possible.

Do not install the drain fitting at the tank's low point (if it leaks you are screw*d), but rather use a siphon dip tube to suction the "effluent" out of the tank.

I installed the Domectic siphon tube kit. You use a drill hole saw to make the hole in the top of the tank, install the bushing then slide the tube (after you cut it to the correct length) into the bushing.

https://marinesan.com/diy-dip-tube-k...SABEgJMzvD_BwE

On the 1-1/2" fittings buy the smooth ones WITHOUT the barbs. They are much easier to slide the hose over, they allow disassembly for repairs (without having to cut/replace hose), and the hose connections are less prone to leak.

The Saniflex hose, although it is much more expensive is definitively the way to go if you want to avoid smelly hoses down the line....

my two cents

cheers