[C320-list] Head leaks and cannot empty tank properly

[kspir4 at cox.net]

Correction:  the SCAD I refer to is a exterior TANK level indicator 

---- kspir4 at cox.net wrote: 
> Thanks Chris.  Rest assured, all my valves are kept close when not in use (27 years in the Navy has taught me that Murphy's Law is alive and well - even if you have two valve protection.  The holding tank is also banded shut when within the mileage limits.  My question is based on finding the tank full a week after emptying it at a pump station.  I know if was full since I took the vent fitting off the top of the tank and could see the liquid at the top.  I also stuck a dowel down the hole to confirm.  I watched the level go down  when I emptied it again at the station.  Once done, I went to the overboard discharge valve handle and pushed hard on it in the event it was not closed all the way.  The good news is I don't think the tank filled again over the past week.  I got to wondering if there was a check valve in the system that would prevent any back filling in the time it takes one to close the overboard discharge after turning off the macerator (a hypothetical question that would help me understand why the tank filled if the valve was inadvertently left open a crack).  I'll follow your suggestion and look up the pump design to either give me peace of mind or something else to worry about if this valve ever fails.  My question was to try to see if anyone has ever had this overboard discharge valve fail and or had the need to replace it.
> 
> To answer your (Chris') other question, yes - the overboard was open when running the macerator.  And yes - the vent comes off the top of the tank; not the pump out line. 
> 
> Sounds like I may have a unique problem.   I actually spoke with one of the Catalina techs at the Annapolis boat show today and he seems to think that restricted flow through the overboard vent fitting is likely the problem.  He recommended the vent piece be replaced (I think I will do that after winterizing although I would have to find a better design piece to replace it - like the stainless pieces aft on the water and fuel systems.  In the mean time, I am going to drill one or two small holes in the lower, outside portion of the plastic vent fitting.  Then I am going to caulk around the through hull - the area I think may be letting some liquid and odor in when the tank gets pressurized due to restricted airflow through the fitting.  However, Ted - you bring up a good point and I will look for possible cracks around the 1.5" pipes.
> 
> Unfortunately I have become quite proficient at removing the medicine cabinet.  Ted: I have tried to attach 2 pix: one of the top of the vent hose behind the cabinet as it leaves the hull.  The other is the vent fitting outside of the hull (photo is from below looking up).  If anyone has this type of fitting I would love to know if they get enough air through it to keep up with the 13GPM macerator pump.
> 
> I also bought a SCAD exterior pump level indicator and will be installing it to help keep from possibly putting fluid in the vent by overfilling/over pressurizing the tank.
> I'll keep you posted on the progress and hopefully the solution.
> Thanks folks,
> Ken
> #1089
> Moondancer
> 
> ---- clburti at gmail.com wrote: 
> > Ken,
> > 
> > I’ll address the last questions first. It has been ages since I disassembled a macerator pump for repair, but believethey are designed to prevent backflow. Look online for a tech drawing of your pump and you can verify this. That said, the through hull valve on the discharge, should never be left open. First for safety reasons, second, in US waters you would be in violation of MSD discharge laws.
> > 
> > 
> > We have a cheap Jabsco head. It doesn’t leave water in the bowl after flushing, so I don’t know whether pulling water out when pumping the macerator is a problem or not. It seems logical that it might do so normally as I can not recall any check valve in the discharge side of the head plumbing.
> > 
> > 
> > There simply should not be any water leaking back into the boat when pumping water out of the vent. I cannot remember what the vent looks like on Commitment as it has been such a non issue for us that I confess that I have neglected to clean it for some time. So I can’t offer any meaningful suggestion other than to figure out how to get it out of the boat so that you can inspect it properly.
> > 
> > 
> > Rereading your original post with this one leaves me a bit confused. Your vent sounds like it is not blocked anymore and even if a bit restricted, should not be affecting operation much. What confuses me is that the vent goes to a separate fitting in the tank than the deck pump out fitting. Pouring water down the deck pump out shouldn’t cause a leak out of the vent unless your tank is full. You state that your tank is being emptied and is full when you return, how are you determining that? To eliminate one possibility, I have to also ask if you are checking to make sure that the through hull valve is actually open  when running the macerator?
> > 
> > 
> > 
> > Fair Winds
> > Chris Burti
> > Commitment
> > Catalina 320, #867
> > 
> > 
> > 
> > From: kspir4 at cox.net
> > Sent: ‎Sunday‎, ‎October‎ ‎13‎, ‎2013 ‎1‎:‎04‎ ‎AM
> > To: C320-List at Catalina320.com
> > Cc: clburti at gmail.com
> > 
> > Thanks Chris.  I've spent a bunch of time on this and found a few things wrong but I think the blocked vent is the biggest culprit and the problem I have yet to resolve.  I have removed the vent hose at the top (at the through hole) and put pressurized water into it.  I could hear the water entering the tank (the hose is clear).  I then reconnected the vent hose at the top and disconnected it at the bottom before putting pressurized water to that end.  The water exited the outside at weak but steady stream.  Unfortunately I also saw some water leak through the caulked seal on the inside near the penetration in the hull (NOT at the hose/hose clamp).  This must be where the smell is coming in the cabin.  After that, I hooked up all the hoses and ran the macerator pump.  I went topside and heard faint hissing at the vent and felt a very very weak suction pulling air in.  Also, the water in the bowl still empties as it is sucked out.   I think the problem is that the "hole" or slit in the vent at the penetration is too small to let a sufficient amount of air in when emptying the take and out when filling the tank.  The way to fix this is not apparent since the holding tank vent is not like the freshwater and fuel vents back aft - the ones with a screened opening on the down side of the vent.  The holding tank vent is a black plastic knob like piece with a indented section on the bottom quarter that does not have an visible opening (I have pictures that I can email to anyone curious and or think they can help).  Does anyone know if this is a standard vent and, if so, can the opening be made or opened more?  Is there a way to easily remove the vent? (I have tried to twist if off without success). I am thinking of drilling a hole in the plastic cover to let more air pass but that will be the last resort since I don't know if that will make matters worse or introduce new problems 
> > 
> > Also, I think I may be getting some leak by though the overboard discharge valve into the tank since I found the tank full after sitting  a week after it was emptied.  Has anyone experienced this?  Is there a check valve in the pump that keeps the water from coming in and filling the tank if the valve is left open or the valve leaks by?
> > 
> > thanks
> > Ken Spiro
> > Moondancer 
> > #1089
> > ---- clburti at gmail.com wrote: 
> > > It is almost a certainty that your vent is blocked...the liquid coming out is being forced out and if the hose clamp is loose or the hose has been forced partially off, liquid will be running down the hose, bulkhead and elsewhere...that liquid is why the aft cabin smells.
> > > 
> > > 
> > > 
> > > Fair Winds
> > > Chris Burti
> > > Commitment
> > > Catalina 320, #867
> > > 
> > > 
> > > 
> > > From: kspir4 at cox.net
> > > Sent: ‎Tuesday‎, ‎September‎ ‎24‎, ‎2013 ‎11‎:‎37‎ ‎AM
> > > To: c320-list at lists.catalina320.com; C320-List at Catalina320.com
> > > 
> > > Hi Folks,
> > > I recently bought a 2006 320 and have had problems with the head from the start.  Many of the problems seem to contradict each other and I was wondering if anyone could help.  First off, I rebuilt the Tetford hand pump so I feel that is working properly (flushing water comes in and waste goes out of the bowl).  I have been using KO solution to help promote decomposition but I don’t think that will help until the problem is fixed.  The symptoms (I know many of them seem to be contradictory) of the problem are:
> > > 1. Waste smell under settee and in the aft cabin.  I believe it is coming from a leak behind the head bulkhead.  I think it only leaks when I pressurize the system with the hand pump.  I do occasionally see some liquid coming down along either the pump out line or the vent line to the bilge near the waste tank.
> > > 2. When I use the macerator, it appears to be able to put a suction on the holding tank since it will usually draw out a little bit of waste.  However, at the end, it will always empty the bowl of any water that was in it.
> > > 3. I have tried to flush the holding tank by putting water in the topside pump out access but it will accept no more than a half-gallon before the tube is filled up and causing some liquid drip from the air vent.
> > > 
> > > I wouldn't think the air vent is blocked since I have some liquid coming out when I fill the pump out tube.  If that is the case, why does the bowl empty when I pull suction with the macerator pump.
> > > 
> > > There doesn’t seem to be any real inspection port to look into the holding tank for blockage or channels.  Is the only means to inspect the inside (without remove the tank entirely) to remove the small air vent port and look through that tiny hole? 
> > > 
> > > Is there an easy way to access the upper hose connections for the pump out hose and air vent to see where the drip is comming from and correcting it when found?  There appears to be an access panel above the shelf that is above the medicine cabinet but it looks like removing it would involve removing some factory caulking that seals the head.
> > > 
> > > Ken