Head Back Flow

[sailpop]

The back flow of the waste remaining in the hose adjacent to the Jabsco pump unit is very common in live aboard situations.

We specifily fixed this problem for a few months at a time by removing and thorougly
cleaning the joker valve AND the flapper valves within the pump handset.

In our experience the usual "crud" buildup on these components dose not take long to permit backflow. When cleaning and inspecting these component if they dont appear to close and seal PERFECTLY we replace with new.

Cheers
Geoff Childs
MISTY of Gosford.
Categories | Sunnypicsoz - Geoff Childs

[CHM]

I just replaced a pump assembly on a Jabsco manual head this week which was not functional at all. What a stinking job it was. To make it more interesting, the angle ofthe discharge waste hose connection on thenpump is different than the original pump and I had to cut a larger opening in the cabinet in the head to get the hose on the new pump. My hands still hurt. I have to go back witha heat gun now to get it installed completely, but it works perfectly for now. On the seacock issue - i keep them closed in the heads unless the head is in use. The only open valves are fromthe engine intake and the air conditioner.

[hlev00]

Originally Posted by CHM

I just replaced a pump assembly on a Jabsco manual head this week which was not functional at all. What a stinking job it was. To make it more interesting, the angle ofthe discharge waste hose connection on thenpump is different than the original pump and I had to cut a larger opening in the cabinet in the head to get the hose on the new pump. My hands still hurt. I have to go back witha heat gun now to get it installed completely, but it works perfectly for now. On the seacock issue - i keep them closed in the heads unless the head is in use. The only open valves are fromthe engine intake and the air conditioner.

I'm sorry to tell you this now but I ran into the same problem and there is a much easier solution. I started to remove the outlet from the old pump to reinstall onto the new pump and discovered that the outlet will rotate. Just loosen the screws a bit, adjust the outlet to the desired angle, and retighten. I actually replaced the joker a year ago for the first time but should have remembered this instead of swearing to myself about Jabsco changing the pump.

[CHM]

Originally Posted by hlev00

I'm sorry to tell you this now but I ran into the same problem and there is a much easier solution. I started to remove the outlet from the old pump to reinstall onto the new pump and discovered that the outlet will rotate. Just loosen the screws a bit, adjust the outlet to the desired angle, and retighten. I actually replaced the joker a year ago for the first time but should have remembered this instead of swearing to myself about Jabsco changing the pump.

I didnt realize this. Thanks. I will have to look at this when i get back on board.

[Colleen-Mae]

The new Jabsco Citrogen replacement, with locking pump solved the problem for us. Old solution was to replace the joker valve. Usually I grease it with Neoprene plumbers grease, but have not had to deal with this after a season and onehalf after replacing with locking pump.

[crosswire]

As one of many Jabsco owners, I am interested in any answer to the blackwater backfill problem. However, none of the messages I reviewed mentioned the flapper valve at the bottom of the pump, the one held "in place" by the twist lock handle. From what I can tell, the joker valve is downstream of this flapper and is only a secondary check valve. The flapper valve seems to be the primary check valve that prevents backflow. During my last rebuild of the head, I made sure the seat for this flapper was clean and smooth and that the flapper was not restricted in movement. The bowl stayed dry for about 4 to 5 weeks until one over zealous crew member dumped a half bottle of deodorizer/tank cleaner in the head (better than matches I guess). Anyway the head started backfilling again. After dismantling, I found the rubber flap valve badly swollen out of shape, possibly due to the chemicals. I suggest a serious look at this flapper valve as it seemed to be the key to stopping leaks in my head; most but not all.

[hlev00]

The joker is downstream when flushing, however it is upstream and the first line of defense to hold back the black water when flushing stops.

After a few years of replacing only the joker valve, last year I our replaced older Jabsco pumps with the current design that incorporates the locking handle. Things were pretty good until last week. Even with the handle in the locked position, we started getting back flow of black water, though not every time. In the past with a deteriorating joker valve, once it started leaking it only got worse. It seems that the source of our problem is from trying to be too gentle at night in an attempt to not wake everyone else up when pumping. These were slow, "quiet" strokes. Once we pumped in a normal manner and locked the handle in place, no back flow. So now I am happily woken up by the flushing sound, knowing that it is helping to keep the black water back flow at bay.

[crosswire]

Yes, the locking handle does help. Remember that the lock works to hold the flapper valve closed and not the joker. Every joker I have replaced has either been held open by crusty deposits in the lips of the valve itself or by a crusty buildup in the valve housing that squeezes the outside of the valve preventing it from closing completely. The flap valves do not seem to experience the same buildup problem.

I have looked at the Sealand gravity heads with the head mounted on top of the tank. These units are usually installed with a small electric pump to rinse the bowl with either salt or fresh water. Neat idea, somewhat expensive, small tank (9 gallons), and usually too big to replace the Jabsco without some cabinet work. BUT, no back flow.

[hlev00]

I spoke too soon. Backflow was constant this weekend. Changed the joker. The old joker was deformed such that it was clear it could not hold back anything. All I had was a Jabsco but I am going to try a raritan next time.


Sent from my iPhone using Cruisers Sailing Forum

[thinwater]

Originally Posted by crosswire

As one of many Jabsco owners, I am interested in any answer to the blackwater backfill problem. However, none of the messages I reviewed mentioned the flapper valve at the bottom of the pump, the one held "in place" by the twist lock handle. From what I can tell, the joker valve is downstream of this flapper and is only a secondary check valve. The flapper valve seems to be the primary check valve that prevents backflow. During my last rebuild of the head, I made sure the seat for this flapper was clean and smooth and that the flapper was not restricted in movement. The bowl stayed dry for about 4 to 5 weeks until one over zealous crew member dumped a half bottle of deodorizer/tank cleaner in the head (better than matches I guess). Anyway the head started backfilling again. After dismantling, I found the rubber flap valve badly swollen out of shape, possibly due to the chemicals. I suggest a serious look at this flapper valve as it seemed to be the key to stopping leaks in my head; most but not all.

The swelling was due to the BLUE chemical. Most of these sterilyzing chemicals contain solvents that can damage head elastomers if not flushed through quickly. They also are poor regarding odor control. THROW the chemical AWAY and never buy it again. Switch to Odorlow of Camco Ultra (something based upon nitrate).

Very likely all of the rubber parts in the head are ruined. You need a new pump asymbly.

No, the joker valve is primary in stopping backflow. Replace the Jabsco valve with a Raritan valve (interchangable). It will last much longer.

But stay way from the sterilyzing treatment. Use only nitrate based treatments. I've done lab and side-by-side testing of many for odor and valve compatibility, and you don't want to use the BLUE treatments.

Also, the joker valves are prone to leakage due to distortion if tightened unevenly, or if the hose applies too much load to the flange. Jabsco's are more sensative, though careful installation solves the problem.

[silversailor]

Most manufacturers suggest changing the joker valve annually. Most sailors wait until the backflow develops. I just changed mine and the backflow stopped immediately!

[thinwater]

Originally Posted by silversailor

Most manufacturers suggest changing the joker valve annually. Most sailors wait until the backflow develops. I just changed mine and the backflow stopped immediately!

That too.

Important tip; the slot goes vertically (otherwise it will droop and leak).