Toilet 'burps' after flushing solid waste-help Head Mistress!

[Terra Nova]

An anecdote.

A client had difficulty with a nearly new waste system. It turned out that she was getting rid of her dog's poop by dumping it down the head. A dog's digestive system is much different than our own. And the almonds she had occasionally been feeding him passed virtually intact, jamming up the joker valve.

[dbSail]

This is the setup - sorry if it sounds simplistic - I am learning. The raw water intake goes to the pump, another hose comes out of the pump and goes up to a plastic loop with a vent on top, then back down to the toilet bowl. The waste discharge goes through the pump/joker valve through a much larger hose to a Y valve, then to the holding tank which is relatively close by 3.5-4ft. Off the tank is a hose to a macerator and a thru hull that's never used and a clear vent hose that leads to the transom. There are no other loops. The vent hose does have a dip as it goes under the sole, then rises gradually when it gets to the lazarette to the vent. It's currently a bare hose end sticking out of a large lazarette vent b/c I haven't been able to fix the corroded connection to the old vent yet and didn't want the lazarette smelling like poo (which is clearly does when someone pumps the head).

I discovered this morning that when I am pumping seawater into the bowl, I hear the vent on the top of the loop suck air. I almost always use fresh water from a jug to flush urine so I don't hear it then. Now that I understand this is all before the bowl I guess that makes sense.

I routinely pump 5 bowls of hot fresh water through while I'm at the pump out with no resistance - pretty aggressive pumping. The only time I've had water not want to go through was this morning after allowing vinegar to sit in the lines all night for whatever that's worth. Working fine now.

So it would seem there's resistance to anything other than pure liquid. I'm not taking anything apart until I go to the pump out which will be this weekend, and I'm going to try the Head Mistress' muriatic acid test, so I will keep you posted.
Thanks everyone for their ideas - I'm learning a lot!
DB

[transmitterdan]

If the vented loop in the sea water side is sucking in air after every pump then that is probably not a problem. That's what it's supposed to do. That loop prevents the system from siphoning water from the sea into the bowl if there is a leak in the sea water pump. So don't close off that vent as the bowl might overflow as a result.

So let's go through how you normally do things. Once you finish pumping you turn off the seawater valve on the hand pump right? Then you pump a little more to get all the water out of the bowl right? After that what happens exactly?

[Stu Jackson]

Head Pumps 101 Why just pouring water into the bowl is NOT a good idea Head Sea Water Shutoff Valve & Antisiphon question