8 April 20007
Head Odors & Preventive Maintenance of the Jabsco Quite Flush
Head odors seem to only be a problem in the forward head. In my
experience the single largest cause of head odors in the forward
head is an incompetent (medical term for not completely sealing)
joker valve. The Jabsco joker valves (the valve that prevents reflux
of toilet waste from the vertical hose/pipe that goes from the toilet
toilet macerator pump outlet to the holding tank) come in tri-cuspid
and bi-cuspid models each carrying the same part number. I
haven't been able to determine if one type is more susceptible to
regurgitation than the other. The soft rubber of the joker valve is
easily contaminated with salt and calcium deposits that render
them susceptible to leakage. Because the forward head has a longer
hose from the macerater pump to the holding tank it also has a
taller column of waste water (more mass = more pressure against
the valve) that the joker valve has to check. It also requires greater
quantities of water to adequately flush so that there isn't grooslly
contaminated fluid standing in the pipe.
Incompetent valve diagnosis: Flush (empty) the toilet bowl completely,
then let it sit for a couple of hours, if there is then ANY fluid in the
bowl after this waiting period it is regurgitated waste water and I
guarantee it will have a bad odor. Replace the joker valve and see
if that doesn't fix your smell problem.
As a matter of careful head and holding tank service I flush the system
with fresh water frequently (use the shower hose) and treat the system
with vinegar water periodically (weekly) to help mitigate salt deposits.
I do this by adding a cup of white vinegar (acetic acid) to a completely
full toilet bowl of fresh water, then emptying the bowl so that the
vinegar water stands in the toilet-to-holding-tank hose for an hour
Also, replace the electric motor shaft seal yearly to prevent leakage
of water onto the motor as a very expensive motor it is.
Gary Silver Amel SM2000 Hull # 335
Quick report on most recent Jabsco Quiet Flush head service: Prior to today, never on the 1ST try have I been able to get the "seal housing" to seal and not leak when re-attaching it to the base of the head with the 4 screws. (Often not on the 2ND or 3RD tries, too.) That is because the O-ring provided by Jabsco service kit, part# 90197-0000 is ever so slightly too big and it won't stay in, even with grease to hold it. Today I got it not to leak on the very 1ST try using a 1.5MM X 75MM O-ring. I'm sure this is a common part, but I got a handful of them from O-Rings West, 2125 196TH ST SW, Suite #114, Lynwood, WA 98036, USA +1 (425) 967-5732 oringswest"dot"com, part #N70-M1.5X75 .
Best to All,
SM384 Sirena Azul
Bill, Ben & the Group,
I didn’t replace the joker/check valve this time because it wasn’t leaking. And (maybe someone can chime in on this..), because in order to replace the joker valve you have to remove the output nipple. But to do that, the only way I have succeeded so far is to use a heat gun to make the output hose flexible enough to bend so as to be able to pull it off of the output nipple. I’m afraid that repeatedly heating the hose every year or so, so as to be able to replace the joker valve and maybe the output nipple, will cause it to fail. I’ve replaced the aft output hose but would like to put off doing a similar job again if at all possible.
For spares I keep at least 1: 24V motor, white round plastic seal housing that screws to the motor, blade & nut kit, output nipples, Jabsco re-build kits, and now a bunch of 1.5MM X 75MM O-rings.
Also as an aside, I’ve replaced some of the four slotted screws that attach the seal housing to the toilet base with hex-drive screws. This solves the problem of the screwdriver constantly slipping out of the screw head as you’re hugging the toilet and watching the flashlight roll away while trying to disassemble or reassemble the unit. I’m not aboard right now so don’t have the size available.
SM384 Sirena Azul
I'll try taking out just the two screws and the niple for the next joker valve change.
I flush with fresh water from the shower most of the time. On the long term to-do wish list is installing a y-valve/selector valve in the engine room for each head's supply to be able to select fresh or sea water supply. Since all vacu-flush heads on other boats are always plumbed with fresh water flush only I don't think there is more than a 1 in 100,000 chance of contaminating the fresh water supply. But if I ever get around to this I will certainly use check/joker valves, and gravity to reduce any posibility of back-flow.