JABSCO HEAD PROBLEM Attention Peggy Hall

[vyv_cox]

Thanks everyone for the responses. Sorry that Peggie (spelling corrected) is not available but I have received some good information just the same. The discharge hoses are relatively recent (perhaps 2 years old) and when I changed them (they were at least 8 years old) they looked a bit like the photo submitted by NormanS.
Depending where we are and what is being deposited in the head determines if it is directed to the holding tank or overboard. I don't see how this makes a difference because the holding tank is lower than the vented loop and Y valve. Anything downstream of the Y valve either flows over the side or into the holding tank by gravity.
The suggestion that salt/urine crystals form in the hose between the head and Y valve and then find their way back into the base valve gasket (flap valve) and cause the leaking back problem is possible. Using fresh water to flush is not an option so I don't know how to prevent that particular problem. I also don't understand why TP would make a difference if the problem is the salt/urine crystals. I will change out the hose from the head to the Y valve again and see what happens but I see this as a short term solution.

The photo was mine. The main deposition of salt crystals occurs in the upward leg between the joker valve and the top of the loop. The point made by others that you pump however many times is needed to completely clear this leg is the way to go, if possible. Don't imagine that once the urine plus seawater is past this point that all your troubles are over! I clean my holding tank out at the end of each season, quite heavily encrusted with salts, and the typical condition of the discharge seacock can be seen at the bottom of this page https://coxengineering.sharepoint.com/Pages/Toilets.aspx

 

[RichardS]

Thanks everyone for the responses. Sorry that Peggie (spelling corrected) is not available but I have received some good information just the same. The discharge hoses are relatively recent (perhaps 2 years old) and when I changed them (they were at least 8 years old) they looked a bit like the photo submitted by NormanS.
Depending where we are and what is being deposited in the head determines if it is directed to the holding tank or overboard. I don't see how this makes a difference because the holding tank is lower than the vented loop and Y valve. Anything downstream of the Y valve either flows over the side or into the holding tank by gravity.
The suggestion that salt/urine crystals form in the hose between the head and Y valve and then find their way back into the base valve gasket (flap valve) and cause the leaking back problem is possible. Using fresh water to flush is not an option so I don't know how to prevent that particular problem. I also don't understand why TP would make a difference if the problem is the salt/urine crystals. I will change out the hose from the head to the Y valve again and see what happens but I see this as a short term solution.

It's not salt or urine crystals in the normal sense which are stopping the bottom valve sealing properly as the seawater passing through the valve will guarantee that a saturated solution is never going to happen and therefore the crystals are never going to come out of solution. The crystals are a largely insoluble compound formed by the interaction between urine and salt water and form where the relative concentration of urine is greatest which is why copious flushing will limit the problem.

Although this "calcite" compound is largely insoluble in water, it is soluble in acid which is why you can hear fizzing when you flush some acid into your toilet system.

Everything else is covered in my post #6.

Richard

 

[prv]

Depending where we are and what is being deposited in the head determines if it is directed to the holding tank or overboard. I don't see how this makes a difference because the holding tank is lower than the vented loop and Y valve.

The reason a holding tank makes a difference is because people are concerned about filling it and so might not pump enough water to fully clear the pipework.

We sail in the Channel where there's less need for a tank, don't have one, and just have the minimum length of hose to make a high loop. We flush every pee through with 20 strokes of the pump to push it all out of the boat immediately. Touch wood no problems with the system, and when I last took the hose off to service the pump the inside of it looked fairly clean.

Pete

 

[sailaboutvic]

We had a similar problem as Vyv , and to remove the pipe would had been a night mare , after pumping HCA we manage to clear most of it ( not all of it ) by using a per of molegrips and squeaking the pipe in different places braking up crystal and then Roding it with an old rigging wire , I doubt we got it all out , but it's working again and save me a lot of bother having to cut hole on he shower to remove the pipe