Jabsco 37010 - Flush Prime

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Pilotpak

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I have a Jabsco 37010 Electric Head, Raw Water flush, mounted slightly above the waterline, and if it hasn't been used for longer than 5 minutes - it seems to loose the prime on the Flush. You need to press the flush button for 15 seconds to get flush water to flow.

I'm toying with the idea of putting a Back-flow valve in the flush line, near the sea-cock, so that when you flush, you get immediate waterflow.

My question is....is it possible that the system is actually designed to backflow, so that there is minimal raw water left in the lines to stagnate between uses ???

Thanks,

Wayne
2006 Larson 310
 
All electric toilets that have a self-priming rubber impeller work pretty much the same way. They don't hold water in the pump and must re-prime themselves with every flush. The rubber impeller is a maintenance item and should be replaced at least every other year, if not every year.

Adding a check valve at the through-hull will help to some degree, but it is one more thing to remember when winterizing the head (there will always be water in the hose between the through-hull and the toilet's pump, which can freeze and cause problems if it isn't addressed when winterizing the head). If you aren't in an area where it freezes over winter, then there won't be any real concern.
 
I have the same model pump and even with a check valve it wasn't that much better. A little growth in the valve and the water would still drain back. Sometimes it would stick shut. I tried several different check valves to no avail.

Ultimately I removed the rubber impeller from the pump, and installed a pressure pump in the line down near the water line (with a strainer), and wired it in parallel with the flush pump. It worked great; primed instantly and best of all it was QUIET!!! It's been in service a couple years now with no issues. I used a Shurflo "Blaster" but Vic might be able to suggest a better one.
 
Bill, that's probably the best solution. The Jabsco rubber impeller pump isn't the greatest, plus it's noisy enough to wake the dead. Shurflo's diaphragm pump quality seems to go back and forth every few years. From the feedback I've been getting lately, they're currently on a "down cycle" as far as their pumps go. But for the price, I doubt you'll find anything much better. Overall, they way you've set it up is vastly superior to the way the head was originally set up - and it's a whole lot quieter in operation! Good job!

For general information purposes, Jabsco invented the self-priming pump that uses a rubber impeller. They had it patented for quite a few years, but the patent has long since expired and many other companies have copied their pump in one form or another - just about every engine cooling pump in a marine application uses a variation of the Jabsco design, plus they're used for all sorts of other things as well: supply water pumps for marine toilets, washdown pumps, oil changing pumps, livewell pumps, light duty irrigation pumps, bilge pumps - and far off into the sunset...
 
Thanks Guys,

Well I am berthed in a "high'growth" area, so I think I'll steer away from the backflow valve and maybe try the pressure pump idea. Will let you know how it goes !
 
Just make sure you install an in-line strainer. The diaphragm pumps are generally reliable but unlike the rubber-impeller type they don't handle trash very well.

Note it doesn't HAVE to have a pressure switch. The switch simply doesn't matter, theres not enough pressure to actuate it. So if you find a comparable pump without the switch you're good to go.
 
Willie...I like your idea but I don't follow how installing a pump will quiet the head. I have the 37010 head too and the combo macerator and raw water pump will wake the dead. I can see eliminating the impellor for the raw water side, but the macerator side still needs to function. Isn't it the motor and macerator itself that is the source of the racket when you flush? What am I missing?
 
Actually the macerator side of the pump is pretty quiet. It's just a chopper blade and a CENTRIFUGAL impeller. Running dry it's almost silent. What makes all the noise is the rubber raw water pump sucking air; then the sound is pumped into the toilet bowl where it reverberates, sorta like tooting a trumpet.

Putting a diaphragm pump in the line does several things:
(1)The pump is inherently quieter.
(2)It's close to or below the water line so it probably won't lose prime.
(3)It's some distance from the head, on the other side of the deck or bulkhead. All these things help.

You can go to the Jabsco web site and pull up the diagrams for their "Quiet Flush" toilets (# 37245); and the #37010. The only real difference is the absence of the rubber impeller pump and the addition of the remote pump. That's essentially what you're building.

It DOES work.
 
Absolutely not!!! [:-banghead] [:-banghead]

Cmariner32, what you're missing is that the macerator isn't what makes all the noise; it is the rubber impeller for the raw water pump that is noisy! The macerator and discharge pump uses a centrifugal impeller that is very quiet. I've done dozens of postings about this in the past.

Removing the rubber intake impeller from the head, and adding a diaphragm intake pump remotely (wire it parallel to the existing toilet pump motor) will reduce the sound level to practically nothing when the toilet is flushing. Nothing needs to be done to the macerator; it remains as-is.

(Willie, you beat me to the punch - my reply was to cmariner32 but you posted your reply first!)
 
Vic... YOU'RE the expert; I'm just another Redneck tinkerer... sometimes I get lucky.

Before I did mine, I contacted Jabsco; they told me it couldn't be done without changing out the whole pump assembly (which of course they'd have been very happy to sell me).
 
Thanks Guys,

I'm about to proceed with this project !

Just one thing worries me... Diaphragm pumps...A guy at our marina had a diaphragm pump on his holding tank overboard dump, and recently the diaphragm failed making quite a smelly mess in the engine bay.

I also have a diaphragm pump on my holding tank dump, and the rubber membrane does seem fairly open and flimsy.

If I mount a diaphragm pump below waterline, and the diaphragm fails, is there not a danger that I will sink ??
 
Hmmm that's a different diaphragm pump. Virtually all the "pressure pumps" available today are diaphragm pumps, but they're not the same as the diaphragm pump you'd use to pump out a holding tank.
They're generally reliable and unless clogged trouble free (that's why you install a strainer). Anyway even if it DID leak the only "spill" would be water.

I thought of using a centrifugal pump ("bait" pumps come to mind) but it would HAVE to be located below the waterline and it MIGHT not put out enough pressure. What I have works (the Shurflo Blaster); and I ain't gonna "fix" it till it breaks. If you decide to go that route please keep us posted.
 
Diaphragm pumps are just as reliable as any other type of pump. But the type of diaphragm pump that is used for a toilet's supply water pump is quite similar to the diaphragm pumps that are used as water pressure pumps, not like those used to pump out holding tanks. They type that is used for pumping out a holding tank is the same that is used as a manual bilge pump - the diaphragm is exposed to the outside. The type we are referring to, has the diaphragm sealed up inside the outer pump housings, and it really couldn't sink the boat unless the outer housing were to break catastrophically.

Further(getting away from toilet pumps), with routine maintenance, a manual bilge pump or pump to empty a holding tank shouldn't be any less reliable than any other pump. Of course you must stay on top of things and replace the diaphragm every few years - in the case of a bilge pump, your life may depend on it.
 
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