Another plumbing question?

[Scott T-Bird]

I'm thinking that I should have known a little bit more about basic plumbing. Last winter, I replaced my toilet (standard jabsco marine toilet), all the hoses and the macerator pump for discharging tank contents to sea. I installed a new electric toilet with fresh water connection. It works great but I'm pretty sure I got one thing wrong. I didn't install a loop from the toilet discharge to the tank. The toilet discharge is about even with the top of the tank. It is a very short run of less than 3' and it feeds by gravity to a discharge at the top of the tank.

What I have noticed is that when I put fresh water in the bowl following a flush, the water never stays in the bowl. It drains very slowly to the tank. I'm guessing that it drains slowly because the water has to go thru the macerator pump that flushes the toilet. I can tell when the tank is full because only then does water remain in the bowl. The side effect is that I can still detect a urine smell in the head - it's not strong but it is annoying until we open the hatch. I assume that I should have fresh water in the bowl to block the hose from back-venting into the head. I think that I should have introduced a small vertical loop so that my fresh water doesn't drain until it's flushed. The original plumbing didn't have a loop, so I didn't think to do this (it was such an easy, short run). I think I will put a loop in this winter and see if there is any improvement.

 

[Peggie Hall HeadMistress]

It works great but I'm pretty sure I got one thing wrong. I didn't install a loop from the toilet discharge to the tank.

A vented loop isn't needed in a discharge line that ONLY goes to the tank.

What I have noticed is that when I put fresh water in the bowl following a flush, the water never stays in the bowl.

Except for the pricy all china "throne" toilets, marine toilets aren't designed to bring in water and hold it. Reason: rockin' and rollin' in messy seas or even just heeling will send water in the bowl all over the head. So unless you don't ever plan to SAIL your boat, forget about the loop to keep water in the bowl.

How fast it drains and whether you have odor seeping back into the bowl--which most likely is from the toilet discharge line, not the tank--depends on how worn your joker valve is and whether you're following each flush with a little clean water to rinse the discharge line. A brand new joker will drain very slowly and will block odor...the bowl will drain faster and allow more odor as the slit opens up more. So if you have odor from the discharge line, you need to do two things. Follow each flush with second clean water flush (only about a a quart) and replace your joker valve.

If the odor IS from the tank, it'll be a sewage smell, not a urine smell. If that's the case, you need to increase ventilation to the tank by replacing the "vent" thru-hull with an open bulkhead thru-hull and switch to a tank product that prevents odor from occurring. No-Flex Digestor is the top rated tank product. Odorlos is another good one...You'll pay a lot less if you get Odorlos from an RV supply store instead of a marine store. Both products are environmentally friendly.

--Peggie

 

[Scott T-Bird]

A vented loop isn't needed in a discharge line that ONLY goes to the tank.

How fast it drains and whether you have odor seeping back into the bowl--which most likely is from the toilet discharge line, not the tank--depends on how worn your joker valve is and whether you're following each flush with a little clean water to rinse the discharge line. A brand new joker will drain very slowly and will block odor...the bowl will drain faster and allow more odor as the slit opens up more. So if you have odor from the discharge line, you need to do two things. Follow each flush with second clean water flush (only about a a quart) and replace your joker valve.

Hmmm, I see your point. I wasn't thinking about a vented loop. Just enough of a rise so that a small amount of fresh water remains in the bowl. And I'm also not talking about filling the bowl to the extent that water sloshes around. Just enough water to fill that small sump at the bottom to block odor like a trap works in household plumbing. All my components (except the tank) are new and installed last spring. Service can only be described as very light at this point in time. Except under very rare circumstance, we only do No #1 when we are staying on the boat - we use marina facilities in lieu of the boat facilities whenever possible. The new toilet is a Raritan Sea Era electric and the joker valve can't possibly be worn unless the factory put in a used one.

Perhaps the issue is that there is just enough rise in the discharge line that a very small amount of water will always be present in the bottom of the bowl. One thing I have observed is that a slug of freshwater never really eliminates the urine in the bowl. It is always mixing with each flush. It seems that it is necessary to dilute it with a highly excessive amount of fresh water to completely eliminate the urine that mixes with the flush water. I typically use the water-saver flush option. Sue tends to use the regular flush option, which is 3 flushes with freshwater. I think we use too much water as it stands (when Sue is on the boat).

I improved the vent and it is an open-bulkhead thru hull fitting. After thoroughly flushing the tank in the past year, we don't have any sewer smell. It is just an annoying urine smell confined to the head when it is fully enclosed for a period of time. (Sort of like walking a typical NYC street ).

 

[Terry Cox]

Hi Scott. Started a thread sometime ago regarding our clogged aft head discharge hose. Long story short, where the old hose connected to the base of the electric toilet, there was a small loop rise, maybe three inches. It was always disappointing to find that any water left in the bowl after flushing would slowly drain into the holding tank.

When I installed the new hose I left a much higher loop (eight inches) and found, to my surprise, that now water after flushing remains in the bowl for the next use, which makes me much happier. It's very easy to empty the bowl when sea state might cause some splashing, but for the most part I really like the idea of having water in the bowl for the next use.