Head Troubleshooting

[Holding Pattern]

Problem: The Groco HF head has been backfilling with waste water. I checked all valves and through all that process you can definitely hear water being pumped into the blackwater tank.
I assumed it was the joker valve or simply something worn in the manual hand flush pump. So using the Groco HF Master Rebuild Kit, rubber gloves, and alot of patience, I rebuilt it this afternoon.
Now it backfills slower than before but backfills nonetheless.
Has anyone had this problem? Any suggestion?

Does the intake water lose prime? I have a Jabsco with both problems,and am about to (yuck) dive into the issue.

[ssullivan]

Does the waste water "back up" through the pump itself, or does it enter somehow when you are trying to pump fresh water into the bowl?

I recently tore apart my head (worst job on a boat, aside from scrubbing the bottom without scuba gear), and the mechanisms are still fresh in my mind.

The only thing that keeps the black water from coming back in is the little flap (one way valve) on mine. Possibly this item is malfunctioning on yours?

[capt lar]

did you check for obstruction on tank vent. if air is not easily escaping, backpressure could force liquid past valve back to head. capt. lar

On mine, the vent plugged with corrosion. I changed the vent, but it did not solve the issue. I am pretty sure I need a rebuild kit, but with how cheap heads have gotten, I think I will swap out the whole unit.

[GordMay]

Marine Head Plumbing - Backflow Prevention:

Vented loops should be installed in all hoses to prevent backflow - but if any part of the system is below the waterline, vented loops must be installed.

I presume you have the Vented Loop between the head discharge & the holding tank?

Grocco Installation Manuals:
Toilet: http://www.groco.net/parts/data/508.pdf
Vented Loops: http://www.groco.net/parts/data/546.pdf

Raritan Installation Instructions - see the Vented Loop in the sectional drawing:
http://www.raritaneng.com/pdf_files/...actIIv0502.pdf

More good information:

“Marine Sanitation: Fact vs. Folklore” ~ by Peggie Hall (The “Head” Mistress)
http://boatbuilding.com/content/sanitation.html
and her book:
http://shop.sailboatowners.com/detai...=400&group=327


HTH,
Gord May

[Holding Pattern]

Yes there is a vented loop and yes it is clear.
I am going to take it apart again and rotate the joker valve - (looks like a duck-bill) 90 degrees.
We have concluded that water is correctly flushing into the tank however what is left from the pump to the top of the vented loop is coming back through the joker valve. The pressure from that residual is coming back thru the valve. The small slit just seems to not be holding the water out.
Getting ready to try that & see.

[GordMay]

Brian & Heather:
While the backflow might be annoying, it is a good indicator that you’ve flushed enough. If the backflow isn’t “clear”, you’ve still got sewerage in the hose, and should flush a little more.
Good idea on the “joker” rotation - it closes by gravity, and stays closed by back pressure.

[JGI417]

have you checked the little rubber valve on the the top of your vented loop for operation, they sometimes stick closed. It should be open when not flushing, and close when your are flushing.

[Alan Wheeler]

Gords spot on about the "pump till clear" part. So are you worrying about the bowl filling with water? or is it a little more nasty coming back down the loop or??? You will never get rid of it all, it wil always come back and fill the bowl just a little. This is good as it provides a seal of sorts to any smells that could come back up the line from the holding tank.