Head problems too

[Dreamboat]

My forward head when I flush it, seems to use the waste water to flush. It doesn't do it all the time but probably about 50% of the time. This obviously leaves smelly water in the bowl.
Not being that familiar with the GM toilets yet, I can't figure out what would be causing this.
Holding tank was just pumped out and that didn't make a difference.
Anybody have any ideas?
As usual, thanks in advance.
Gary

 

[MikeP]

I'm not sure what you mean by "using waste water to flush" but if you mean that the head will sometimes "back fill" with waste water, that is typically caused by a worn stator in the waste side of the head pump. A damaged rotor could also be the cause and a bad rotor will quickly wear out a new stator but GM rotors are pretty robust. If I correctly understand the description, what is happening is that waste water is being pumped up hill at some point to the tank and the rotor/stator is not sealing the output properly. Additionally, if you have that problem and the head valve is switched to dump directly overboard, the head will fill to the boat's water line level. The same thing can happen on the intake side if it's a raw water head - if the rotor/stator does not seal, the bowl can fill with raw water (as opposed to waste water).

Vented loops will eliminate the problem regardless of the state of the stator/rotor in the pump. Interestingly, although GM shows vented loops in the installation instructions for the head, Hatteras - at least on our 1980 53MY and other 53/58s I have seen - did not install the heads with vented loops. I'm not sure why, perhaps Hatt figured that since the head bowl is above the water line level, it couldn't actually overflow regardless of the state of the pump...

When was the last time the pump had new stators installed?

 

[carolinacoast]

We did not have vented loops either, and installed them when we went with the Raritan atlantes FW system.

 

[Dreamboat]

Mike
What I was trying to say was: When I flush the toilet, instead of seeing fresh water come in, sometimes it looks like it is sewage that is coming in on the flush cycle.
System is plumbed to discharge into the holding tank as opposed to overboard
Gary

 

[MikeP]

Hmmm…when you flush the head and observe it when that happens, is the "waste" water coming from the rim of the bowl into the head or is it entering from the bottom of the bowl?

I know this may sound silly but if you have raw water heads, depending on where you are cruising/anchored, the water can be quite murky. We anchor regularly on the Chester River where the "flush" water in the bowl sometimes looks decidedly disgusting - though it has no odor, it just looks "dirty." I will admit that is one thing about raw water heads that I don't like…

 

[tonytrakovich]

I have seen this on my old GM heads as well. When you flush, you get a blackish water that the toilet is using to rinse the bowl. I had sea water flush heads and I expected some discoloration is some places. But this was black in color and had a fowl smell. It was not waste. It happened when we flushed a clean bowl also.

I have since replaced 3 of my heads with fresh water flush Techmas. Great heads. The forward birth still has GM head.

I really noticed the problem after long periods of inactivity. To me, it looks like the inside of the hose is deteriorating during the inactivity and going into the bowl on a flush. Or, the inside of the fresh water side of the pump is doing it?

Never had the same problem with the Techmas.

 

[MikeP]

If it sits long enough, the seawater sitting in the system will "spoil" and it will take several flushes - maybe quite a few - to flush out the "bad" water which could be discolored as well as smelly.

 

[Dreamboat]

Mike
The waste water is coming from the rim. It wasn't a case of the boat sitting too long. It happened during a week's vacation where it was being used frequently. The boat is sitting in fresh water, which is pretty clear so I don't think its sucking in this dirty water from outside. The water that is coming from the flush cycle when it happens definitely smells and looks like sewage.
Having said all this, this weekend it didn't act up at all.