Raritan HF Pump resistance

[RLaird]

Regret to ask a question that has probably been asked gazzilion times.
Hoping the Head Mistress can make it simple but open to all feedback. ( I did try to search with some marginal results
[Short version: Takes a lot of pressure to push liquid from the bowl to HT]


I serviced my head this year. Older boat relatively new to me with lots of lacking maintenance for many years prior to my purchase.


I installed the basic 'kit' with joker and a few seals. I lubed things up nicely, I thought. Of course I found that one of the four screws on the service plate was stripped. (seems pretty common as my 'spare' HF has the same issue)


To the point, went to the pump-out as I found that it took excessive effort to pump into the holding tank, which I had essentially not been using as I am dock side still. I pulled significant liquid from the tank (only use for #1). Back at the dock locked out the new Y valve to the holding tank side. Found that it is a high pressure effort to direct liquid into the freshly emptied tank.


I expect the answer is in the vent line being blocked? Yes, once I find the source at the tank I will try to figure out how to enlarge the line!


Thanks for your patience in reading!
Rob

[peghall]

For openers, the HF marine toilet isn't a Raritan, it's a Groco compact toilet, so I'm wondering if you put the right kit in it. However, if you could flush it directly overboard without a problem, I agree that a blocked tank vent is prob'ly the source of your problem...and a blocked tank vent would not only pressurize the tank, creating back pressure that would prevent flushing the toilet, but it would also prevent a pumpout from pulling more than a few gallons.

The two most common locations for a vent blockage are the vent thru-hull and the other end of the vent line--that end of the hose and the vent fitting on the tank.

Start by cleaning out the thru-hull...use a screwdriver blade, ice pick--whatever works. If there's a screen in the thru-hull, knock it out...screens cause more problems than they prevent. If that doesn't result in a spew out the vent, you'll need to relieve the pressure before removing the vent line from the tank to clean them out, although, if there was no spew when you opened deck pumpout cap, the pressure may have dissipated UNLESS you've used the toilet since then. If you have, open the deck pumpout fitting VERY CAREFULLY with a hose at the ready and be e sure you're UPwind of it! Scrape out that end of the vent line and the vent fitting on the tank...reconnect the vent line. Replace your existing vent thru-hull with a 1" bulkhead (aka "mushroom") thru-hull.

Thanks to a li'l doodad called the Uniseal UNISEAL, enlarging the vent line is easy if you have enough clearance above the tank to use a hole saw on power drill. A short piece of PVC pipe that has a 1" OUTER diameter (to fit into a 1" hose) It shouldn't extend more than an inch into the tank and extend above the tank only high enough to slip a hose onto it far enough to double clamp it.


--Peggie

[RLaird]

Thanks Peggie!
Yes, that would be the 'Oh-Duah'. It is a Groco of course.
I tried using a power washer today after the wire wouldn't make the trip. No luck.
I can relieve the pressure by switching the (new) Y valve to overboard.
Now I just have to figure out how to get into the remote slot where they chose to place the vent in the transom. I could touch it but getting tools on there to disassemble should be fun.
I think I'll start at the tank end if I can find it. (the vent hose that is). The tank is pretty well covered by the starboard lazarett. It's there somewhere!
Thanks for your thoughts and I have enjoyed your book.
Stay well,
Rob

[peghall]

I tried using a power washer today after the wire wouldn't make the trip.

What did you try to do the with power washer???? What wire? And what did you try o accomplish with it?

I can relieve the pressure by switching the (new) Y valve to overboard

That can relieve the BACK pressure that prevents your toilet from flushing but it can't de-pressurize the tank. Doing that requires clearing the vent blockage, which is most likely in the vent thru-hull and the other end of the vent line.


One more time: start by scraping out the thru-hull--which you can easily find because it's on the OUTside of the hull/transom. Inside the boat, the vent fitting is at the top of the tank, most likely on the end or side that's closest to the transom.

Once you succeed in clearing the vent, I'd give serious though to finding another location for the tank, 'cuz venting it out the transom makes the air exchange necessary to keep the tank aerobic (essential to odor prevention) impossible. Plus, I'd bet at least a dollar that it's way too far from the toilet.

I'll be glad to help you with that project.

--Peggie

[RLaird]

Hi Peggie,
The head is strbd aft in cabin separated from the tank by a hanging locker so quite close. Maybe 3 or four feet.
I only had some 12 gauge electric wire which made the 90 degree bend but only proceeded about 6 inches. Not rigid enough.
I had a power washer on board from a project on my just sold vessel.
I tried directing the stream up into the vent. Water seemed to make it into the loop based on some flow out when I removed the nozzle from the head of the vent.
I plan to try and locate the vent tap at the tank. The hull liner makes some things a huge challenge...

Thanks much for your feedback
If you can recommend a wire style that would snake thru the hose I’d be interested!

Best wishes
Rob

[peghall]

I tried directing the stream up into the vent. Water seemed to make it into the loop based on some flow out when I removed the nozzle from the head of the vent.

A loop in a vent line is needed in water and fuel tank vents to keep sea water out of the water and fuel tanks. But there should NOT be a loop in a waste tank vent line...that one needs to be as short and as close to absolutely STRAIGHT as possible.

As for snaking the vent line with a wire...I doubt you'll find anything in the vent line, but even if you do it'll just leave with a bunch of loose stuff in the line to build up on the blockage at the tank. You're gonna have to do what it takes to gain access to the tank and fittings. if you're ever gonna have a clear vent...and you'll need to replace the existing "vent" thru-hull--which is designed to keep sea water out water and fuel tanks--with an open bulkhead thru-hull that'll let you prevent future vent blockages by sticking a hose nozzle against it to back flush it every time you wash the boat.

--Peggie