galley sink drain

[karista]

I am mystified as to why  all of the sudden my galley sink  takes forever to drain empty. I have used the "search" feature and am familiar with Captain. Al's changes etc.
In order to correct this problem, I first replaced the check-valve attached to the Reefer drain pump as it was bad, did not correct the slow drain. Then I replaced all the sink drain lines and fittings including sink drain hardware--everything-- still no improvement.Then I hired a diver to check the Thru-hull for barnacles, it was clean, when opened, water gushes in. I then hooked up one galley sink drain directly to the thruhull valve (same as head sink drain hook-up), still no improvement, yet the head sink drains very quickly. What I don't understand is why is the head sink drains so quickly and the galley sink (One bowl hook-up) does not drain.
I connected a clear 1" dia vinyl tube to the thru hull and routed it out and up so I could check the water level when the valve is op end the seawater level appears to be only about 2" below the sink bowl, could this be the cause? But then again I have had the boat for 15 years, thus the water level I am sure has not changed. Bottom line after doing everything I know, to fix the no/extremely slow drain situation I have made now headway! Any ideas???    

Bernd Mueller

[Gary Ambrose]

When we purchased our 1986 C 34 last year we found a small plunger stored in the area under the sink. Always wondered about that. A few weeks ago our sink would not drain. Out came the plunger, applied it to the sink and Voila! No problems since.

[Ray & Sandy Erps]

Sounds like an obstruction somewhere.  We found out that coffee grounds and our sink drain don't mix.  I've cleared the obstruction before by putting water in the sink to fill the lines then plug the sink drains and then pump like heck on the ice box foot pump to force air bubbles into the line and out the thru-hull fitting.  All that sloshing around and gurgling worked for me.  We're very careful to keep coffee grounds out of the sink now.

[Jim Fitch]

Bernd -

It sounds like you've checked everything so I can't answer the mystery but I've found that when a through hull fitting gets clogged with barnacles or mussels that you can remove the hose, open the valve and work your biggest Phillips head screw driver through the valve to clear the obstruction.  It takes only a few seconds with that water rushing in and saves either jumping in or hiring a diver.

Jim
Sunshine
#1103
Scituate, MA

[Ron Hill]

Bernd : You've got an obstruction.  From what you've said about replacing everything down to the thru-hull, I'll guess that it's in the thru hull fitting/barb.  You can take the barb fitting off of the thru hull and check it.   You can also take a 4" sink drain rubber disk and put it on the outside of the hull and remove the thru hull.  The water pressure will hold that disk in place.  

The only thing that I can tell you, is to work a 3/8" wooden dowel in that thru hull and make sure it's clean/unobstructed.  It's a tough place (the sink drain thru hull) to work from on the inside.  
Did your diver or someone poke to make sure the thru hull was clear from the underside?  
Another thing to do is use a plumbers helper/pump from the topside.  Close off one sink drain and work the "heck" out of the other.

Every so often I put some bleach in that drain and let it sit for a couple of hours with the thru hull off.  Just make sure that the sink water level is below your new sink drain fixtures as bleach will tend to rust stainless.  Then I use a plumbers helper very gingerly to circulate the water (still have the thru hull closed).  Then I open the thru hull and the inside sink PVC pipe is sparkling clean.  

My advice may be disjointed, but you get the idea.  Good Luck  

[Ken Juul]

I second the plunger idea. The sink drain upgrade was my first major project after buying the boat, but we still find that it takes very little to plug the sink.  Even though we scrape all the food scraps into the trash, bits of food, especially lettuce, combined with grease/oil will slow it every time.  Especially if I'm in the conserve water mode and don't thoroughly flush the drain after doing the dishes.  Minor plugs can be handled with both drains open, for tough ones using a stopper or drain disk in one side to get better suction really helps.  Use the plunger to suck the offending blockage into the sink then let it drain.

[Roland Gendreau]

I experienced the exact same problem with my 1992. I didnt have a plunger so I used an air horn to blow the drain clear, pressing the palm of my hand on the other drain to hold the pressure. I was amazed how much back pressure there was...more later.

The air horn blow didnt help at all.  So I completely removed all the drain hose only to find out there was no obstruction.

So I opened up the sea cock with the hose disconnected and sea water flowed right up. No obstruction there either.

So my conclusion was that the drain hose was way undersized...I replaced  the hose with 1 " 1/4 pvc piping and installed new sink baskets at the same time.   In the process of doing this, I found that there was a dime in the thru hull...acting as a perfect check valve.  It would let sea water in, but wouldnt let the drain water out except at a very slow rate. Thats why there was so much backpressure when I tried to use the air horn to blow the drains clear!

So I agree with the other posters above, check the thru hull for obstrucions.

Roland
Gratitude #1138

[Castellanet]

The bottom of the sink is close to the water line, so there's not much pressure.  This bothered me for a couple years until I learned what to do: simply plunge the sink with the palm of your hand.  A good hand palm plunging works for me every time.  Please don't use bleach, the fish don't like it.

[karista]

Thanks for the input, I used the plunger idea and this ultimately solved this mystery. Using the plunger, the water drained out, then however there was a immediate air burping sound and then it would no longer drain. The problem was a air blockage, caused by the center tee connection of the 2 bowls. The center barb (drain) of the tee was parallel to the bottom of the bowl, causing this air blockage. By pointing it downward the sink again drained correctly.
Bernd Mueller