Electric Flush Mod to Manual Head

[zstine]

After finding myself out cruising with a full holding tank and no pump out, I've decided to add a macerator pump so I can pump out myself. Since I'm getting a pump, why not also plumb it to suck my toilet bowl dry? I'd like to keep the manual function too. Can I use a macerator to empty the bowl through the flapper and joker valves? If not, I can use the clean-out, but that complicates the plumbing. Anyone have experience with this? BTW, the toilet is well below the waterline and gravity fills. I would just wait for the bowl to fill 1/2 way, close the intake valve, and push the flush button.. Then watch in amazement as the bowl empties like magic! Electric flush for ~$100!
thanks,
zach

[model 10]

Gack.

[peghall]

After finding myself out cruising with a full holding tank and no pump out, I've decided to add a macerator pump so I can pump out myself.

That's fine as long as you understand that you can only use it in open sea at least 3 miles from the nearest point in the whole US coastline. (If you're not in the US, refer to the legla requirements for the country you're in).

Can I use a macerator to empty the bowl through the flapper and joker valves?

You can't use the same macerator pump to empty both the toilet and the tank, so you'd need a second macerator. You'd also have to remove the toilet pump, which means you'd no longer have any way to bring flush water in, and also because the macerator pump and the manual pump won't move bowl contents at anywhere near the same rate...so you'd be constantly "frying" impellers in the macerator and or creating backups in the discharge line. Bottom line: it's a bad idea, but if it any consolation, you're not the first person to think of it.

If you want a macerating electric toilet, replace the manual pump with a real macerating electric toilet. Most toilet mfrs offer "conversion" that replace everything south of the bowl, reducing the price considerably...only about twice the price of a macerator pump. Any bowl that mounts using a 4-bolt + pattern will fit any of the "conversions." IMO the Raritan SeaEra SeaEra Conversion Kit is the best choice, but the only one I'd advise you to avoid is the Jabsco 29200, which only replaces the manual pump with what even Jabsco admits is a very poor excuse for an electric toilet.


Wiring it according to mfr's specs is critical to trouble free operation. So the right wire size for the distance to the battery (which is always the round trip distance) is essential...as is the need to have enough power for the toilet. All electric toilets--even including your bad idea of installing a macerator pump inline--need to be on their own separate dedicated circuit, shared by nothing else that can pull power away from it 'cuz low voltage will quickly destroy any electric motor.

BTW, the toilet is well below the waterline and gravity fills.

That's NOT how it or ANY toilet should be installed...in fact, it's a good way to sink a boat! Read the installation instructions for your toilet and install it correctly. If you don't have the instructions, you can get them from the mfr's website. I'll send you the link if you'll tell me the make/model.

[zstine]

Originally Posted by peghall

That's fine as long as you understand that you can only use it in open sea at least 3 miles . .

I am aware and island hopping planned. so no issues there.

Originally Posted by peghall

You can't use the same macerator pump to empty both the toilet and the tank, so you'd need a second macerator.

Is this another government rule like the 3 miles?.. certainly it is physically possible to have both the tank and toilet piped to the pump.

Originally Posted by peghall

You'd also have to remove the toilet pump,

Why can't I have the manual toilet's discharge hose plumbed to the macerator and leave the manual pump? It should suck bowl water through the flapper and joker vlave. Or if you think the joker valve will clog, then pipe the bowl clean-out to the macerator, like Lavac toilets. That skips the manual pump without removing it or disabling it.

An electric toilet doesn't solve the primary issue... a full holding tank with no way to empty it while out cruising in the middle of nowhere.

Originally Posted by peghall

BTW, the toilet is well below the waterline and gravity fills

I know that is not per current ABYC standard, But that's how the boat was delivered from the factory. i didn't do it. Besides, it provides me with 15 seconds of lazy bliss as i watch the bowl fill wondering how long it would take to sink if I passed out at that very moment.. time to flush...

[peghall]

You can't use the same macerator pump to empty both the toilet and the tank, so you'd need a second macerator.
Is this another government rule like the 3 miles?.. certainly it is physically possible to have both the tank and toilet piped to the pump.

No gov't rule against it. So do it that way if you don't mind watching your holding tank contents fill up and overflow your toilet bowl. Yes, I'm sure you'll install y-valves to prevent that...but you'll only have to leave it open to the "wrong" side for that happen. Lavac toilets don't use the same macererator pump to dump the tank and flush the toilet...converting a Lavac to electric requires replacing the manual diaphragm pump with an electric pump.

An electric toilet doesn't solve the primary issue... a full holding tank with no way to empty it while out cruising in the middle of nowhere.

You'd install the macerator to dump the tank...an electric toilet "conversion" to replace your manual toilet pump.

Why can't I have the manual toilet's discharge hose plumbed to the macerator and leave the manual pump?

All toilets come from the factory plumbed for above waterline installation..It's up to boat owners to make the changes necessary for below waterline installation. You've not only failed to do that, but if your toilet fills "by gravity," it means the wet/dry cam assembly--which is only marginal protection at best--has failed...leaving you with -0- protection against sinking if you should fail to close the intake seacock before leaving the boat or turning in for the night.

So to answer your question, on a boat on which the toilet is plumbed correctly, the suction from the macerator would mess up the seals, o-rings etc in the pump because it wouldn't just pull what's in the bowl, but it'll pull through the pump too...on your boat the macerator will also pull flush water IN through the pump, starting a siphon that you'll only be able to stop by closing the intake thru-hull.

Good luck with it!

[zstine]

Thank you Peghall for your reply. You have made some assumptions about my system and stated conclusions that are not true.

You assume 1) that my holding tank is above the toilet level 2) that only one valve separates the pump out line from the toilet discharge, 3) that my wet/dry cam valve is failed (it has not) and 4) that effluent back-flowing into my toilet would go unnoticed. I'm also guessing that your statement that the manual pump seals would get destroyed if I put a suction on them was an assumption, not an experience. Also, there's no way for the macerator to pull in raw water causing a siphon unless the piston in the pump has failed, b/c the 2 sides (raw water and sewage) are positively separated by the piston. I conclude you are making statements without any real experience with experimenting on a manual pump toilet in the manner I'm describing.

I understand the lavac and industry standard install as described. I wouldn't be asking for help here if I wanted to do the same standard thing... Progress never happens that way! I won't spend nearly $1,000 to buy an electric head plus a macerator and mics parts, when I believe I can get similar or more functionality for $200.

Is there anyone else with real experience in this matter? I've heard (separate forum) that a cheap macerator like the Jabsco 18590 will not have enough suction to flush a toilet. Is this true?

I have attached my proposed plumbing schematic. let me know if you need anything explained. Note the following allowable functionality:
- Electric flush to holding tank
- Electric flush to overboard
- Manual flush to holding tank
- Manual flush to overboard
- Electric tank pump out to overboard
- standard pump out

[meridian28]

I believe Peggy Hall has been in the head business before you were born. She knows of what she writes.


Sent from my iPhone using Cruisers Sailing Forum

[AlwaysFORSAIL]

I have converted two electric heads to manual and one manual to electric. I think that manual heads are head (pun intended) and shoulders above electric flush. Mainly because manual heads will flush as long as you can work the pump. Electric heads will stop working for several reasons.

By all or any means get your head above water.

And, I have a new Elctra Scan system that I started to install and did not. It was connected to power but not to poop so it is virtually new. I am selling my boat and the Electra Scan separately. Write to jcvillines@gmail.com if you are interested. The boat is a 2001 Hunter 380.

[mitiempo]

Originally Posted by zstine

I understand the lavac and industry standard install as described. I wouldn't be asking for help here if I wanted to do the same standard thing... Progress never happens that way! I won't spend nearly $1,000 to buy an electric head plus a macerator and mics parts, when I believe I can get similar or more functionality for $200.

Macerator pumps - or any other impeller pump for that matter - are not designed to suck and are terrible at it. They are designed to push. That is one of the reasons your idea will not work.

I doubt you could effectively pump through the manual pump in any case, at least without gutting it.

I'm guessing you have the Jabsco manual head, one of if not the least expensive in the world. It is standard on many boats whether they are expensive or not. If installed below the waterline the hose from the pump to the back of the bowl needs to be replaced by an appropriate hose with an anti-siphon at a point higher than the waterline at any normal angle of heel. This is in the manual. The supplied hose is also not the proper type to be used below the waterline. Any sharp surveyor wouldn't pass an installation without this.

This is from the manual:

[AlwaysFORSAIL]

You can design and install a 'better mouse trap' but keep in mind that Peggy Hall has done a ton of research, practice and gone through many years of trial and error. All of the advice I saw from others is in agreement with Peggy Hall. That is not to say that your efforts won't be successful.

Keep in mind that human waste on a boat is a very nasty thing when not contained.

[peghall]

The ONLY assumption I made was that the wet-dry cam assembly in the toilet has failed...and that was based on your saying that your toilet fills "by gravity." YOU assumed I made the rest of 'em.

About your schematic: You want to be able to flush using either the manual pump or the macerator. That will require TWO y-valves-which you seem to show in your schematic--that will allow the toilet to bypass the macerator because the manual pump will not push the waste through it. Forget to change even one of them and you'll have a mess. If it were a good idea, at least one toilet mfr somewhere on the planet would offer such a "dual flush system"...and one of 'em may have tried it at some time. It wouldn't be the only bad idea that lasted only a very short time on the market....the combination pumpout/overboard discharge deck fitting that Jabsco introduced in the early '80s may be the worst idea ever! But...if that's what you want to do, it's your boat. Good luck with it.

[Mithril Bham]

Appreciate your innovative spirit but bad idea.

[Stu Jackson]

I have been active on internet forums for as long as we've had our boat in 1998. Peggie has already written her book back then.

Listen to Peggie, she is THE world-wide expert on head systems and boat odors.