Wasn't sure what to call this. I have an electric head in the boat I just bought. It is set up to be filled with fresh water. The process is: Flush, turn fresh water valve on to fill the head, then turn it off. But here is my problem. When it is flushed waste water returns to fill the bowl (to the level it was at). When I turn on the fresh water it adds to the contents of the bowl and I pump it out but the water is never clean even after several fillings and pumpings. My planned fix is to add a check valve right after the head outlet. Is this ok? It seems to me the head itself should have a check valve. Maybe it does but it doesn't work? All advice appreciated. Mike
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Best Guess
Sounds like the vented loop is missing from the discharge line between the head and holding tank or the one that is there is not working properly. In the event that you are not familiar with the set up. Track the discharge line from the bottom of your head. Somewhere between there and the holding tank is a half circle pipe, either black plastic or possibly bronze, with a small valve on the top. It will be mounted to a bulkhead or something rigid. It's purpose is to keep you from getting the backflow that you are obviously getting. It will be mounted slightly higher than the head. If that's what it is, it's a cheap fix. Good Luck!
Sounds like the vented loop is missing from the discharge line between the head and holding tank or the one that is there is not working properly. In the event that you are not familiar with the set up. Track the discharge line from the bottom of your head. Somewhere between there and the holding tank is a half circle pipe, either black plastic or possibly bronze, with a small valve on the top. It will be mounted to a bulkhead or something rigid. It's purpose is to keep you from getting the backflow that you are obviously getting. It will be mounted slightly higher than the head. If that's what it is, it's a cheap fix. Good Luck!
You have problems you don't even know about!
Starting with, a previous owner has apparently connected a toilet designed to use raw water to the potable fresh water system....'cuz that's not the way any marine toilet I know of is designed to flush. That's a MAJOR no-no. No marine toilet that isn't specifically designed to use pressurized water should ever be connected to the fresh water system 'cuz there's no way to do it without risk of polluting the fresh water supply, damage to the toilet...or both. So whatever is backing up your toilet, the first thing you have to do is convert it back! Replacing the toilet may make more sense. There are several possible reasons why your toilet won't flush...the most obvious is a blocked holding tank vent, creating backpressure. Other possibilities (none of which include anything to do with a vented loop...sorry, JB): Low voltage to the toilet due to corroded connections, a weak battery, too far from the battery, wire size too small. Put a volt meter on it while you flush it...if it's not reading the full 12v, you have low voltage. If you're in salt water, sea water calcium carbonate buildup in the head discharge hose can reduce the hose diameter enough to create enough backpressure to back up the toilet. It can be dissolved, but since I suspect the only sensible way to solve ALL your problems is a new toilet, new hoses too would be the easiest way to cure it. A long uphill run to the tank would allow some runback, but it should only be clean flush water, there shouldn't be any waste in it. The toilet may need rebuilding...rebuild kits include a joker valve that goes in the head discharge...and the last thing you need is another one. Or the toilet may just be worn out..everything has a lifespan. Do you have a clue what the make/model/age is?
Starting with, a previous owner has apparently connected a toilet designed to use raw water to the potable fresh water system....'cuz that's not the way any marine toilet I know of is designed to flush. That's a MAJOR no-no. No marine toilet that isn't specifically designed to use pressurized water should ever be connected to the fresh water system 'cuz there's no way to do it without risk of polluting the fresh water supply, damage to the toilet...or both. So whatever is backing up your toilet, the first thing you have to do is convert it back! Replacing the toilet may make more sense. There are several possible reasons why your toilet won't flush...the most obvious is a blocked holding tank vent, creating backpressure. Other possibilities (none of which include anything to do with a vented loop...sorry, JB): Low voltage to the toilet due to corroded connections, a weak battery, too far from the battery, wire size too small. Put a volt meter on it while you flush it...if it's not reading the full 12v, you have low voltage. If you're in salt water, sea water calcium carbonate buildup in the head discharge hose can reduce the hose diameter enough to create enough backpressure to back up the toilet. It can be dissolved, but since I suspect the only sensible way to solve ALL your problems is a new toilet, new hoses too would be the easiest way to cure it. A long uphill run to the tank would allow some runback, but it should only be clean flush water, there shouldn't be any waste in it. The toilet may need rebuilding...rebuild kits include a joker valve that goes in the head discharge...and the last thing you need is another one. Or the toilet may just be worn out..everything has a lifespan. Do you have a clue what the make/model/age is?
More info
I need to describe my problem a little better based on your questions. When I flush the head it empties ok but then sits there and fills back up (it pulses as the water flows back in). The fresh water comes from the on board tank. It is pressurized by a 12v pump. I thought it was ok to use fresh water to flush a head. If so, should it be set up differently? The hose run to the holding tank is about 5' uphill. Thanks for the help. Mike
I need to describe my problem a little better based on your questions. When I flush the head it empties ok but then sits there and fills back up (it pulses as the water flows back in). The fresh water comes from the on board tank. It is pressurized by a 12v pump. I thought it was ok to use fresh water to flush a head. If so, should it be set up differently? The hose run to the holding tank is about 5' uphill. Thanks for the help. Mike
Check it anyway
Check your vented loop anyway. The reason they are manufactured and installed in boats is to prevent a siphon action from your holding tank to the head. If your head is functioning properly, the valve in the loop being stopped up can cause the back flow. The valve on the top of it can get stopped up and can easily be cleaned. If you still have the problem, continue on up the line until you find the problem. The vent to the holding tank could also be stopped up causing positive pressure in the tank forcing it's contents back into the head. Check the cheapest stuff first.
Check your vented loop anyway. The reason they are manufactured and installed in boats is to prevent a siphon action from your holding tank to the head. If your head is functioning properly, the valve in the loop being stopped up can cause the back flow. The valve on the top of it can get stopped up and can easily be cleaned. If you still have the problem, continue on up the line until you find the problem. The vent to the holding tank could also be stopped up causing positive pressure in the tank forcing it's contents back into the head. Check the cheapest stuff first.
R,L...you don't really understand vented loops...
'Cuz if you did, you'd know that there's no way a siphon can start in the head discharge line between the toilet and the tank...the tank would would have to be full to overflowing even to get it started...and once the level in the tank drops below the the top of the inlet fitting, that would allow air into the hose that would break any siphon. Vented loops are only needed inlines connected to below-waterline thru-hulls, where the water supply is endless. In a line between the toilet and a tank, their only function is to provide a "hill" higher than waste can climb over when the boat is heeled and the tank inlet fitting is in a location that would allow waste in the tank to flow back toward the head. As long as there's a loop, it doesn't matter whether it's vented or not. Nor is it possible for a siphon to start in the opposite direction that water (or waste) is being pushed or pulled. A siphon has to be a continuation of water flow...it can't reverse course. That alone eliminates anything to do with vented loops as the cause of water flushed out of the toilet backing up into the toilet.
'Cuz if you did, you'd know that there's no way a siphon can start in the head discharge line between the toilet and the tank...the tank would would have to be full to overflowing even to get it started...and once the level in the tank drops below the the top of the inlet fitting, that would allow air into the hose that would break any siphon. Vented loops are only needed inlines connected to below-waterline thru-hulls, where the water supply is endless. In a line between the toilet and a tank, their only function is to provide a "hill" higher than waste can climb over when the boat is heeled and the tank inlet fitting is in a location that would allow waste in the tank to flow back toward the head. As long as there's a loop, it doesn't matter whether it's vented or not. Nor is it possible for a siphon to start in the opposite direction that water (or waste) is being pushed or pulled. A siphon has to be a continuation of water flow...it can't reverse course. That alone eliminates anything to do with vented loops as the cause of water flushed out of the toilet backing up into the toilet.
Something is sending it back...
Since your head discharge hose runs uphill for 5', my guess is whatever is in the head is running back downhill. Unless you're able to flush long enough to send everything that's in the bowl AND rinse out that whole 5" behind it, the runback will be bowl contents mixed with flush water. The joker valve in the toilet should slow it down considerably...reduce it to slow seepage, but it can't prevent it completely. Pulsing indicates a blockage somewhere--possibly a blocked tank vent, possibly buildup in the head discharge hose. No...it's NOT ok to use fresh water to flush toilets that aren't designed to use pressurized water unless you a) only pour it in with a cup, b)connect the toilet intake to separate flush water tank, or c) the toilet is a model specifically designed to use pressurized flush water. Toilets designed to draw in raw water don't have the necessary siphon breaks, air valves, and backflow preventers to prevent contamination of the fresh water supply, and most are designed to handle the increased water pressure either. So yes...it most certainly should be set up differently...the intake hose on the toilet should be connected to a below-waterline thru-hull. However, I'm not sure that's still possible with your current toilet...'cuz the only way it work as you described is by removing the intak pump. So IMO, replacing the whole system is your best option... a new toilet that works the way it's designed to work...rerouting the head discharge to create a mostly down hill run to the tank (which may require a new location for the tank, but maybe not)...and new hoses. More than you want to do now...but you'll be glad you did in the long run. My book covers all this in a LOT more detail than is practical to post here...you can see the whole table of contents at the link below.
Since your head discharge hose runs uphill for 5', my guess is whatever is in the head is running back downhill. Unless you're able to flush long enough to send everything that's in the bowl AND rinse out that whole 5" behind it, the runback will be bowl contents mixed with flush water. The joker valve in the toilet should slow it down considerably...reduce it to slow seepage, but it can't prevent it completely. Pulsing indicates a blockage somewhere--possibly a blocked tank vent, possibly buildup in the head discharge hose. No...it's NOT ok to use fresh water to flush toilets that aren't designed to use pressurized water unless you a) only pour it in with a cup, b)connect the toilet intake to separate flush water tank, or c) the toilet is a model specifically designed to use pressurized flush water. Toilets designed to draw in raw water don't have the necessary siphon breaks, air valves, and backflow preventers to prevent contamination of the fresh water supply, and most are designed to handle the increased water pressure either. So yes...it most certainly should be set up differently...the intake hose on the toilet should be connected to a below-waterline thru-hull. However, I'm not sure that's still possible with your current toilet...'cuz the only way it work as you described is by removing the intak pump. So IMO, replacing the whole system is your best option... a new toilet that works the way it's designed to work...rerouting the head discharge to create a mostly down hill run to the tank (which may require a new location for the tank, but maybe not)...and new hoses. More than you want to do now...but you'll be glad you did in the long run. My book covers all this in a LOT more detail than is practical to post here...you can see the whole table of contents at the link below.
Peggy!
That was some pretty interesting reading and good information. How did a lady ever get interested in specializing on boat plumbing? I've changed lines and did routine maintenance on mine over the years and it never seemed like anything that a woman would be particularly interested in. Nasty stuff, know what I mean?
That was some pretty interesting reading and good information. How did a lady ever get interested in specializing on boat plumbing? I've changed lines and did routine maintenance on mine over the years and it never seemed like anything that a woman would be particularly interested in. Nasty stuff, know what I mean?
It's only natural...
After all, who changes most of the diapers in this world? Women! We've been up to our elbows in it since Eve slapped the first fig leaf on Cain's bottom. I was kinda forced into learning about boat plumbing when I bought the first boat big enough to have a toilet and a holding tank...the odor was UNBEARABLE...nothing on the marine store shelves helped--some things only made it worse...and all anyone in the marine industry had to offer was "boats with toilets stink...boats with holding tank stink worse." I refused to settle for that and began a learning curve that first allowed me to cure ALL the odor on my own boat...then led to accidentally starting my own company--which required learning more...sold my company 15 years and a lot of knowledge later...and then organized all the basics into a book (link below). I'd been in advertising for the previous 20 years...some people don't think that going into the onboard waste business was much of a career leap.
After all, who changes most of the diapers in this world? Women! We've been up to our elbows in it since Eve slapped the first fig leaf on Cain's bottom. I was kinda forced into learning about boat plumbing when I bought the first boat big enough to have a toilet and a holding tank...the odor was UNBEARABLE...nothing on the marine store shelves helped--some things only made it worse...and all anyone in the marine industry had to offer was "boats with toilets stink...boats with holding tank stink worse." I refused to settle for that and began a learning curve that first allowed me to cure ALL the odor on my own boat...then led to accidentally starting my own company--which required learning more...sold my company 15 years and a lot of knowledge later...and then organized all the basics into a book (link below). I'd been in advertising for the previous 20 years...some people don't think that going into the onboard waste business was much of a career leap.
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