Macerator Toilet in wet head, custom build, or PHII

[Sassriverrat]

Good Morning,

As I work to finish a new build (hull is finished, now outfitting), I've been stuck in my head design. I'm putting in a wet shower. Holding tank is fiberglass with a 1.5" inlet (about 5' of piping from the toilet) and has a 2" drain off the toilet. Tank can gravity drain out of the hull, so no concern there. Finally, I have a spare Raritan PHII toilet bowl laying around. I've been seriously debating whether to rebuild that (need a new pump casing totally), build a custom head with a macerator using the bowl, or to go with something like an elegance or a dometic (maybe 7120 or 7160). Mostly worried about draining that tank. Anyone have any input on this?

Only concern with the electric toilet is 1. The pump in wettish (no underwater, but spray from shower) environment or having an impeller cook. These toilets used to have a bad rep and I was hoping to get some input.

Note: Tank is 25 gallons- so reducing pumpouts and therefore water is nice but I am on a budget (less than $750).

Thanks!

[Dogscout]

Jabsco Lite Flush. Macerates very well, pumps and motors are protected.

[malbert73]

Rarity an elegance. Phenomenal. Everything lives under the bowl. Mine gets wet all the time. 4 years flawless

[Sassriverrat]

Any idea on water usage of the elegance compared to the PHII?

Also, anyone know if dometic stuff is comparable in quality to raritan? I know raritan makes the sea era conversion for the PHII bowl but it’s not worth the cost. Didn’t know how dometic compares.

[peghall]

Any idea on water usage of the elegance compared to the PHII?

The user controls the amount of flush water with the PHII and also the Elegance if you include the optional "Smart Flush" panel that offers 4 flush choices--bring water in and hold it in the bowl ahead of use (doing that ahead of solids will greatly reduce the amount of flush water needed to clean the bowl), dry flush, "light" flush and "full" flush.

Also, anyone know if dometic stuff is comparable in quality to raritan?

Better than Jabsco, but not the same quality as Raritan.

I know raritan makes the sea era conversion for the PHII bowl but it’s not worth the cost.

Hopkins Carter Marine Hopkins-Carter Marine Supply and Fishing Tackle has the SeaEra conversion for $425. They have the Raritan Marine Elegance--with the SmartFlush panel--for under $750 Hopkins Carter Marine Raritan Marine Elegance


--Peggie

[Sassriverrat]

Yes I do understand the user preference on water usage but trying to figure out how much water moves in one pump of the head (like we used to do 10 pumps on a raritan PEII for pee, 25 for #2) so I can plan against something like an elegance.

Peggy: do you have any opinion on the dometic 7100 series?

Also and most importantly: what are the common failure points- especially in a wet head? Thinking like steel bearings on the pump, impeller, etc. thanks!!

[peghall]

For one thing, like a lot of people you've never learned to use the dry mode to do more than just push the last of the water out of the bowl. The PHII can easily move bowl contents at least 6' in the DRY mode. So pumping 10-25 x is just filling up your tank with flush water, when you only need to use enough to rinse the hose behind the flush.

And the same would be true with the Marine Elegance...which btw, has a pump that can move bowl contents up to 30'! As for common failure points in a wet head, I know of none.

I haven't seen enough from Dometic macerating toilet owners to have an opinion about any model. Their first MasterFlush toilets were made in Romania, but I'm unable to find out where they're made now.

--Peggie

[malbert73]

Originally Posted by peghall

For one thing, like a lot of people you've never learned to use the dry mode to do more than just push the last of the water out of the bowl. The PHII can easily move bowl contents at least 6' in the DRY mode. So pumping 10-25 x is just filling up your tank with flush water, when you only need to use enough to rinse the hose behind the flush.

And the same would be true with the Marine Elegance...which btw, has a pump that can move bowl contents up to 30'! As for common failure points in a wet head, I know of none.

I haven't seen enough from Dometic macerating toilet owners to have an opinion about any model. Their first MasterFlush toilets were made in Romania, but I'm unable to find out where they're made now.

--Peggie

Hi Peggie-
Follow-up question- when you mean my elegance can move bowl contents 30 feet- you don’t mean in dry mode do you? I thought it’s pump needs to be primed with liquid to move anything

[Sassriverrat]

Peggie- I understand what you're saying with the "dry mode" on the PHII but we always are cognizant to both flush the lines (and the fact that we're sending everything nearly 65' on my dad's boat) but the system works like a champ.

I, also, was under the impression that all macerating toilets had to have water to flush and dry running the pump was an issue. Anyone have any idea the bore and stroke of the PHII and then I can compute how much water is used per pump.

Sounds like the PHII is about as water-efficient as they come (forgetting vacuum) at this rate....

[peghall]

I, also, was under the impression that all macerating toilets had to have water to flush and dry running the pump was an issue.

That's true of ALMOST all of 'em because almost all of 'em have intake impellers that can be "fried" by dry friction heat. But the Raritan SeaEra has a diaphragm intake pump and the Elegance needs a remote pump to supply sea water (it's actually designed to use pressurized fresh water that needs no intake pump, but can also use sea water)...and because the remote pump pulls sea water into itself, then PUSHES it to the toilet, the Elegance can--and does--have a "dry" flush mode if you have the multi-function flush panel.

Anyone have any idea the bore and stroke of the PHII and then I can compute how much water is used per pump.

I think this may answer that question...written for me by Vic Willman (now retired) who was with Raritan for 40 years, as plant manager before he spent about 15 years as tech services manager. He was my guru:
"The diameter of the piston of the PHII is 2 1/2 inches. The diameter of the piston of most other manual toilets is 1 3/4". Now this doesn't sound like much of a difference, but given the same length of stroke up and down, for demonstration purposes we'll say 2 1/2 inches for each head that we're considering. When you calculate the cubic inch capacity (displacement) of the PHII with a 2 1/2" diameter piston, it comes out to a little over 12 cubic inches. If you do the same calculation for a pump with a 1 3/4" diameter piston, with the same 2 1/2" stroke, the cubic inch capacity is only 6 cubic inches. So, to put that all into English, the PHII will pump twice as much per stroke, as it's competitors will. Adding the lever-type handle, there isn't as much actual effort required. So, in a nutshell, you only have to pump half as many times to flush it, and your arm doesn't get as tired. Plus, with the lever handle, you don't have to bend over as far, with your nose practically in the bowl, while you're pumping it."

But there's something else that has a major impact on the efficiency of ALL manual toilets: the joker valve:

Most people think that the only thing the joker valve does is acts as a check valve to stop backflow from returning to the toilet or odor from the tank from escaping through the toilet. But that's not a joker valve's most important function...in fact, the joker valve is THE single most important replaceable part in a manual toilet.
Here’s how the discharge half of the pump works and why the joker valve should be replaced at least annually: On the upstroke of the piston, a vacuum is created in the area beneath the piston. This causes the joker valve to close tightly, and the flapper valve beneath the pump to open, allowing some of the contents of the toilet bowl to be drawn into the bottom half of the pump. Then, on the down stroke of the piston, the flapper valve is slammed shut, and the effluent is forced out of the bottom of the pump, through the joker valve, and off down the line. But when the joker valve becomes worn and/or there's a buildup of sea water minerals on it, it can no longer seal tightly on the upstroke of the piston...less vacuum is generated when you pump it. And as it becomes more worn less and less vacuum, till finally the bowl contents simply move up and down a bit, but don't go anywhere. Sometimes the flapper valve needs to be replaced too, which is why toilets should also be rebuilt at least every 5-6 years as PREVENTIVE MAINTENANCE.
You prob'ly won't notice the loss of efficiency at first because it's so gradual...same as we don't see that we've gotten a little older than we were yesterday when we look in the mirror each morning. But I guarantee you that if it's been two years or longer since you replaced the joker valve, you need to pump the toilet at least 50% more times to move the bowl contents to the tank or all the way out the thru-hull....IF they're getting there at all any more.

--Peggie

[Sassriverrat]

Hmmm.... not sure if my math is right here but should be (it was the basis for my physics background).

If the PHII has a 2.5" bore and stroke (and I don't have mine in front of me to check), then it should be 3.14 x 2.5 x 2.5 x 2.5 = 49.09 cubic inches. Divide that by 231 to get to gallons and that's about 0.2 gallons (1/5 of a gallon!) per flush. That's a lot of water suddenly. Even just putting one pump in the toilet before flushing and then flushing that is pretty close to a quart per flush....seems much less efficient (but it doesn't have power consumption!).

Can someone verify this as it seems way too much, but maybe not.

[Mike Banks]

One can buy a quality in-line macerator pump which can be connected to pretty much any well designed head bowl. I used the TMC el-cheapo heads, which had their own macerator pumps built on to the bowl. I used these on advice from a commercial operator who used them and no others, and he replaced them every two years regardless. I had mine for five years without any problems in the main heads, used by two people living aboard full time and one in the ensuite aft cabin which had little use and was also completely trouble-free.

The only thing I would say if you are using the same cubicle for a sit-down shower and a heads as well, as do some vessels and caravans, is to have a simple bowl with an in-line macerator located OUT of the cubicle and so that no electrical equipment except the flush switch is likely to get water on it, and I covered the recessed push-button waterproof press-and-hold switch too. I did this not because my shower was in the heads compartment, but because it was below a portlight and it may get rain or salt water on it in a blow.
The flush switch carries a low current and is used only to activate a remote 30 amp relay, which provides the current to the macerator pump, which draws 15 amps nominally.

In line macerator pumps need to have liquid in them at all times, so if you have a water maker, put excess fresh water into a separate tank that serves the heads and have it connected to nothing else. A simple bladder tank will do, fifty litres does a few flushes.

If one is living aboard, seawater is fine. It is only if stagnant that it turns into a strongly acid sulphurous stinking disaster.

I have seen people using filtered recycled freshwater shower water for flushing the heads--which is OK if one is living aboard, but if left stagnant in the heads bowl and pipes, will smell almost as bad as does putrid seawater.

[Sassriverrat]

The building of a custom head was a side thought that didn't seem bad- water usage is a problem because I only have 25 usable gallons and want to go at least a week without a problem- I never knew how much water my dad's boat was actually going through because we could open the tank all the time, but as I remember, a boat I delivered was a 20 gallon tank and we were filling it every 4 days or so i think