backflow - Jabsco Compact Head

Peggie Hall HeadMistress · May 31, 2011

Water runs downhill...

In my Moody 44, there is a manual Jabsco compact head forward - I believe it's below the waterline. It has the waste hose that goes up to a Y - then to either the tank or a thru-hull. I notices it back flows into the head. I did try adding a vented loop - same issue.

Whatever is left in the toilet discharge line between the bowl and the top of the loop (or the wye) will run back down to the toilet. So you need to pump longer in the dry mode...that will move 95% of it over the top of the loop.

Don't heads have a built-in backflow preventer?

The joker valve should only allow slow seepage...but that's not its primary function. It's a rubber part that should be replaced annually--or AT LEAST every two years--as preventive maintenance.

I also noticed that the raw water adds to the same issue but I did have the valve closed just to be sure the water was coming from the waste hose.

A vented loop is needed in the intake to prevent that...without one, if the thru-hull is left open when no one is aboard, the boat could sink in its slip. The intake vented loop does NOT go in the line between the thru-hull and the pump...it has to go between the pump and the bowl, as shown in the installation instructions for your toilet:
Jabsco 29090 -3000 Twist 'n' Lock manual toilet instructions (does't matter whether yours is the "twist n' lock" version, the instructions are the same for ALL versions). And it needs to be at least 6-8" above waterline AT ANY ANGLE OF HEEL...which on most sailboats puts it 2-3 FEET above the bowl. See attached photo

Ron20324 · Jun 6, 2011

The joker is a regular-maintenance item. Yes, it has to be replaced once in a while. If you get backflow, replace the joker first. That solves my back-flow problems. I think I've replace mine 3 times in 5 years. It's only 2 screws, but be sure to pump clean water through the lines first to clear out the dirty stuff. When you put the 2 screws back in, tighten them alternately maybe one revolution per tighten unitll it's tight.

Head Master18695 · Jun 7, 2011

If you change the joker valve annually, and keep the vents cleared out on the vented loop fittings, you shouldn't have any problem. As you said, it's a maintenance issue.

Peggie Hall HeadMistress · Jun 7, 2011

I know what I'd do...

I'm debating whether I will replace the joker valve and maybe other parts on this Jabsco or just get the same size Compact II or PHC Raritan.

You do have a maintenance issue, but even the most scrupulous maintenance can't do much for a cheap flimsy piece of equipment. So I wouldn't put ANY money into the Jabsco, except MAYBE a new joker valve. Anything more, it would be more cost effective to replace the whole pump--which costs only slightly more than the service kit, and which a surprising number people do every year.(Rick Dinon, have you kept your promise yet? :dance: ) IMO it makes a lot more sense to upgrade to a better quality toilet that that you only have to buy once to have a couple of decades of reliable trouble-free service is you only rebuild every 5-6 years and keep it lubricated.

Raritan discontinued the Compact II at the end of last year in favor the PHC as their compact manual toilet. And the PHC is what I'd buy. You can even recycle your existing bowl, seat and lid, AND save a bunch of money too, by going with the "conversion"...check that out here: sbo.com PHII PHC LBA

The PHC uses the PH II pump...Raritan just figured out how to put it on a compact base to fit in a tighter space...and the PH II pump has been rated the best toilet in it's class for more two decades...so yes, it is well built.

Les · Jun 7, 2011

I like to add to what Peggy just wrote. I have a relatively new Hunter 27 that had a Jabsco compact toilet. There is a saying on the docks that this toilet will break whether you use them or not. I believe it to be true. So recently my wife bought from this web site the conversion kit for the Raratan PHC that Peggy recommended. It was a romantic birthday gift don't you think? And it is now installed using the existing bowl, seat and lid. You can feel the difference in the pump, no doubt about it. But over the years in different boat I have installed at least five Raritan PH II heads. I can't disagree with Peggy--it is the smart move and the way to go.

njsail · Jun 8, 2011

Interesting idea. I would love to convert but....I have a door that swings inward and I think it would hit the pump handle. The jabsco is straight up and down and fits the space. I need need to figure out some accurate measurements this weekend. I've been through a couple of Jabsco pumps in the last two years (The whole head unit is only 2 years old). I even have a spare pump now.

I had a Raritan head in my last boat and besides a few rubber parts worked great for a decade until I sold the boat.

Ron20324 · Jun 8, 2011

njsail said:
... I've been through a couple of Jabsco pumps in the last two years (The whole head unit is only 2 years old)

You might be doing something wrong if you're needing to replace the entire pump, as parts are available. My Jab is going on 6 years and only needed a couple of jocker replacements.

Peggie Hall HeadMistress · Jun 8, 2011

You THINK the door would hit the pump handle...

...But you don't KNOW that it will...so find out! If it does, there are solutions:

The PHC handle is about 4" shorter than the PH II handle...it might not block the door after all. But if it does, you could cut off another inch or so. Or...

Put the pump on the other side of the bowl. Or...

Leave the pump handle in the up position.

Ron...you've gotten lucky. You haven't had to find out first hand that it's cheaper to replace the pump than it is to buy parts for it.

njsail · Jun 8, 2011

Re: You THINK the door would hit the pump handle...

I agree with you Peggy. I haven't had a chance to get back to the boat after this mornings revelation there is a cross brand pump available for the Jabsco head unit. One of the first things I plan on doing is a quick measure. I also just purchased a tank monitoring system from Dennis Ferriello. Hopefully I can install it this weekend as well. It's a tough choice....sail or work on the boat. When the hook sets and the boat settles in I can relax. Drinks magically appear in my hand and I start to forget all about the things that need fixing while watching the sun set. Having a boat filled with pretty women in skimpy bathing suits doesn't help the boat work cause much either (and I'm not complaining one bit). It just stresses the fact that head better pump or the party is over.

WayneH · Jun 13, 2011

OK, Late to the party but let me add my experience. My Jabsco was backflowing with a vented loop. I bought the service kit from SBO. And found out while I was servicing the pump that the flapper valves were corroded and the joker valve was well aged and not seating off properly. Now when I empty the bowl, it stays empty.

That said, if I need to rework this issue this year, I'll probably take Peggie's advice and upgrade the works to a Raritan.

Peggie Hall HeadMistress · Jun 13, 2011

If that's your only issue...

Replace the joker valve annually (preventive maintenance needed by ALL manual toilets) and learn to flush long enough in the dry mode to move bowl contents over the top of the vented loop.

Rick D · Jun 24, 2011

DanColucci said:
So - the Raritan head is installed and everything is now working as it should. Regards - Dan

So, Dan, what's your impression of it so far?

Peggie Hall HeadMistress · Jun 27, 2011

Two solutions (three, actually):

PHC/PHII pump can be mounted on either side of the bowl...so try it on the other side.

Cut another inch off the handle...or...

No requirement that the handle has to be left in the down position...if the door won't close with it down, leave it up.

backflow - Jabsco Compact Head

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