Groco HF head - The toilet seems to flush and pump-dry OK but, after I pump dry, the bowl backfills with waste water from the holding tank (yea nasty). Is there some way to fix this? Should I replace the pump assembly? The valves? Also, there is a lot of friction and the pump feels like it needs to be lubricated - other posts suggested vegatable oil, is this a good idea? Thanks.
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most common reason
for this is a blocked holding tank vent which causes back pressure to push waste back into the bowl.
for this is a blocked holding tank vent which causes back pressure to push waste back into the bowl.
Lubricate
Take pump apart and lubricate the piston at least once per year,check flapper and maybe replace with new. Nick
Take pump apart and lubricate the piston at least once per year,check flapper and maybe replace with new. Nick
Don's right...your tank vent is blocked
It sounds like your toilet also needs lubrication, but that's not why you're experiencing backflow. A blocked tank vent pressurizes the tank, creating backpressure that sends flushes back to the bowl. It'll also prevent a tank from being pumped out. A tank vent--ALL tank vents, water fuel and waste--have two primary functions: to provide an escape for air displaced by incoming material...and to provide a source of air to replace material as it's pulled out. When the vent becomes blocked, the system becomes pressurized, preventing anything from getting into the tank..it also causes pumps to pull a vacuum that prevents anything from being pulled out. Continuing to use the toilet against a blocked vent can have consequences you don't even want to think about--an eruption in the toilet, an eruption on deck when you open the deck pumpout fitting, even a cracked tank. A strong pumpout pulling against a blocked vent can implode a tank. So do not use the toilet or attempt to pumpout till the vent is clear The most common locations for a blockage are the vent thru-hull and the connection to the tank, both the fitting and that end of the hose. So first, scrape out the thru-hull with a screwdriver blade (if there's a screen in, remove it). If that's where the only blockage is, you may get an eruption out the vent, so watch where you're standing. If it's not the only blockage--if there's also one at the tank--you need to relieve the pressure in the tank before removing the vent line from the tank fitting. Loosen the deck pumpout cap VERY carefully...hang onto it...and have a hose at the ready. Or, if you're lucky, the pressure may have dissipated through the toilet. But I wouldn't remove any hoses till you're sure. It's essential to keep the vent open...to make sure it stays that way, backflush it every time you wash the boat and/or pump out. For more details on how to maintain a toilet and tank, you might want to check out the link below.
It sounds like your toilet also needs lubrication, but that's not why you're experiencing backflow. A blocked tank vent pressurizes the tank, creating backpressure that sends flushes back to the bowl. It'll also prevent a tank from being pumped out. A tank vent--ALL tank vents, water fuel and waste--have two primary functions: to provide an escape for air displaced by incoming material...and to provide a source of air to replace material as it's pulled out. When the vent becomes blocked, the system becomes pressurized, preventing anything from getting into the tank..it also causes pumps to pull a vacuum that prevents anything from being pulled out. Continuing to use the toilet against a blocked vent can have consequences you don't even want to think about--an eruption in the toilet, an eruption on deck when you open the deck pumpout fitting, even a cracked tank. A strong pumpout pulling against a blocked vent can implode a tank. So do not use the toilet or attempt to pumpout till the vent is clear The most common locations for a blockage are the vent thru-hull and the connection to the tank, both the fitting and that end of the hose. So first, scrape out the thru-hull with a screwdriver blade (if there's a screen in, remove it). If that's where the only blockage is, you may get an eruption out the vent, so watch where you're standing. If it's not the only blockage--if there's also one at the tank--you need to relieve the pressure in the tank before removing the vent line from the tank fitting. Loosen the deck pumpout cap VERY carefully...hang onto it...and have a hose at the ready. Or, if you're lucky, the pressure may have dissipated through the toilet. But I wouldn't remove any hoses till you're sure. It's essential to keep the vent open...to make sure it stays that way, backflush it every time you wash the boat and/or pump out. For more details on how to maintain a toilet and tank, you might want to check out the link below.
Nick, it's not the piston that needs lubrication...
It's the inside of the cylinder. The piston rod never comes in contact with anything...it's the seals and o-rings ON the piston rod that rub against the inside of the cylinder wall and deteriorate from friction if the wall isn't kept well lubricated. You don't have to take the pump apart to lubricate it...you just need access to the inside of the pump to put a healthy squirt of thick teflon grease into it. it's a 10 minute job once a year. Or you can fight the never-ending battle of flushing a weekly tablespoon (any more will just wash out the first time you pump the toilet) of vegetable or mineral oil--I prefer mineral oil--down the toilet. I'd rather just do it once a year and be done with it.
It's the inside of the cylinder. The piston rod never comes in contact with anything...it's the seals and o-rings ON the piston rod that rub against the inside of the cylinder wall and deteriorate from friction if the wall isn't kept well lubricated. You don't have to take the pump apart to lubricate it...you just need access to the inside of the pump to put a healthy squirt of thick teflon grease into it. it's a 10 minute job once a year. Or you can fight the never-ending battle of flushing a weekly tablespoon (any more will just wash out the first time you pump the toilet) of vegetable or mineral oil--I prefer mineral oil--down the toilet. I'd rather just do it once a year and be done with it.
My old Jabsco would do this
when the tank got mostly full. It had nothing to do with the vent. Mine was just plumbed so that there would be some siphon back pressure from the tank when it got near to full. It is all better now. I replaced the holding tank and plumbed it with 1 1/4 inch schedule 40 PVC pipe. It rises about 18 inches from the outlet of the head and flows back and down hill into the top of the new tank. Veeery slick new $130 Jabsco head with the locking handle. The pipe, fittings, new head and 28 gallon tank cost about $250 including tax. It took three long and stinky days. After removing the old tank, I took two showers and still felt a little uneasy.
when the tank got mostly full. It had nothing to do with the vent. Mine was just plumbed so that there would be some siphon back pressure from the tank when it got near to full. It is all better now. I replaced the holding tank and plumbed it with 1 1/4 inch schedule 40 PVC pipe. It rises about 18 inches from the outlet of the head and flows back and down hill into the top of the new tank. Veeery slick new $130 Jabsco head with the locking handle. The pipe, fittings, new head and 28 gallon tank cost about $250 including tax. It took three long and stinky days. After removing the old tank, I took two showers and still felt a little uneasy.
Patrick. the real reason YOU had backflow
was because your tank inlet fitting was located to allow waste to run back toward the toilet when the boat was heeled. The 18" rise in the piping from the toilet to the tank was the cure...although moving the inlet fitting on the tank from the outboard side to the inboard side of it would also have solved the problem. Unless your tank was leaking, you didn't need a new tank...unless your hoses were permeated, you didn't need new piping--hard or hose...and you didn't need a new toilet unless you were having problems with the toilet itself. But hey, every boat owner needs expensive war stories, whether it was actually necessary to go to war or not.
was because your tank inlet fitting was located to allow waste to run back toward the toilet when the boat was heeled. The 18" rise in the piping from the toilet to the tank was the cure...although moving the inlet fitting on the tank from the outboard side to the inboard side of it would also have solved the problem. Unless your tank was leaking, you didn't need a new tank...unless your hoses were permeated, you didn't need new piping--hard or hose...and you didn't need a new toilet unless you were having problems with the toilet itself. But hey, every boat owner needs expensive war stories, whether it was actually necessary to go to war or not.
Sorry Peggy, war is sometimes necessary
Heeling had nothing at all to do with my backflow issue. It was due to the fact that the old flex hose was routed along or below the toilet outlet until it reached the back of the boat. There it rose to the upper side of the tank. When the tank contents were above that point, there was enough back pressure for it to flow back into the old head and it was always sewage coming back. Poor design if you ask me. Sewage always in the hose, aluminum tank just waiting to spring a leak. It really stank after 18 years. I have intel that says so. The intel has been triple checked and verified. There have been reports on every visit to the boat that I needed to do something. No one else would even consider helping. It did this back flow at the dock many times. It never overflowed there but it would sure fill up the bowl to the rim. I guess it would have overflowed if the boat had heeled in that state of fill but I like to pump out before I sail. The new Jabsco head has a locking handle which is supposed to stop backflow but that would not help the smell from the old hose or the risk of the tank leaking. Using a $4 PVC pipe instead of $150 worth of flex hose made it possible to put the pipe along the hull in back of the hanging locker and shelves. It completely supports itself and looks ok too. I doubt it will smell again in my kids lifetime. The only real drawback is that it took a lot of carpentry to put the pipe in place. I would estimate that it was not really much more work than putting in new flex hose and bending it back into the old routing holes. From what I hear, $250 for a new holding tank, new head, and new plumbing is cheap. Estimates I got were more than ten times that to hire it out. I am just going to declare "Mission Accomplished" and move on to relocating the batteries. The need for that war is a little more debatable but I am going in guns ablazing. I do not care what congress thinks. They are just a bunch of cowards, morons, perverts, and traitors. Anyway you get the idea...
Heeling had nothing at all to do with my backflow issue. It was due to the fact that the old flex hose was routed along or below the toilet outlet until it reached the back of the boat. There it rose to the upper side of the tank. When the tank contents were above that point, there was enough back pressure for it to flow back into the old head and it was always sewage coming back. Poor design if you ask me. Sewage always in the hose, aluminum tank just waiting to spring a leak. It really stank after 18 years. I have intel that says so. The intel has been triple checked and verified. There have been reports on every visit to the boat that I needed to do something. No one else would even consider helping. It did this back flow at the dock many times. It never overflowed there but it would sure fill up the bowl to the rim. I guess it would have overflowed if the boat had heeled in that state of fill but I like to pump out before I sail. The new Jabsco head has a locking handle which is supposed to stop backflow but that would not help the smell from the old hose or the risk of the tank leaking. Using a $4 PVC pipe instead of $150 worth of flex hose made it possible to put the pipe along the hull in back of the hanging locker and shelves. It completely supports itself and looks ok too. I doubt it will smell again in my kids lifetime. The only real drawback is that it took a lot of carpentry to put the pipe in place. I would estimate that it was not really much more work than putting in new flex hose and bending it back into the old routing holes. From what I hear, $250 for a new holding tank, new head, and new plumbing is cheap. Estimates I got were more than ten times that to hire it out. I am just going to declare "Mission Accomplished" and move on to relocating the batteries. The need for that war is a little more debatable but I am going in guns ablazing. I do not care what congress thinks. They are just a bunch of cowards, morons, perverts, and traitors. Anyway you get the idea...
Thanks, Thanks, Thanks, but more questions...
Great advice, thanks thanks thanks, my next step is to check the vent line. But I have some follow-up questions: 1) I did pump-out (fortunatly, I did not get an explosion of waste in the face when I opened the waste cap) and I could hear air being sucked in the vent. So at least some air is getting through the vent line, could this still be my problem???? 2)How do I access the inside of the cylinder to lubricate it on the HF pump assembly??? And a dumb question, is this a dirty job??? Thanks again! So glad to have the "Mistress" involved.
Great advice, thanks thanks thanks, my next step is to check the vent line. But I have some follow-up questions: 1) I did pump-out (fortunatly, I did not get an explosion of waste in the face when I opened the waste cap) and I could hear air being sucked in the vent. So at least some air is getting through the vent line, could this still be my problem???? 2)How do I access the inside of the cylinder to lubricate it on the HF pump assembly??? And a dumb question, is this a dirty job??? Thanks again! So glad to have the "Mistress" involved.
I had the exact same problem in my Groco HF on my Hunter 88 H40
Eventual waste backfill. Was all set to dump it and replace it etc etc but found what I realized was a joker valve when rummaging through some of the POs parts box. I installed it over a month ago and voila ... no more problem! took me all of 10 min to install too!
Eventual waste backfill. Was all set to dump it and replace it etc etc but found what I realized was a joker valve when rummaging through some of the POs parts box. I installed it over a month ago and voila ... no more problem! took me all of 10 min to install too!
Oh and yeah I stuck a hose into the vent and sprayed to unclog
the vent. That didnt help. It was the Joker Valve. its rubber and deforms over time. Normal wear
the vent. That didnt help. It was the Joker Valve. its rubber and deforms over time. Normal wear
Wast water backing up into the Groco bowl
There are only three things that I know of that can cause your problem. The most likely reason is a bad joker valve. If not that, you will have to get down and dirty and check the piston rings. If not that, you should check the vented loop valve to make sure it is not clogged. All the Best,
There are only three things that I know of that can cause your problem. The most likely reason is a bad joker valve. If not that, you will have to get down and dirty and check the piston rings. If not that, you should check the vented loop valve to make sure it is not clogged. All the Best,
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