bubbling on the top of vented loop

[simdim]

Folks,
I had noticed that every time the head is flushed there are bubbling on the vented loop in the hanging locker. Does that mean that line is obstructed or it is just a failure of a valve?

Cheers,

Simon

[waterdog]

Simon,

I assume this is a vented loop on the intake.    If the vent is positioned between the intake thru hull and the head, you have a problem.   The hose there would have suction and it will suck a lot of air through the vent with any water it gets.  It will make a lot of noise.       

If the vented loop is between pump base and the bowl, it is in the correct position.   If it is making a bubbing noise here, you want unscrew the top, check the little rubber fitting and make sure everything is clean and functioning properly.    Is water coming out the top of the loop?   

[simdim]

Steve,
This vent is between head pump and holding tank. I just want to make sure that there would not be a material hitting the fan if I unscrew the vent.

Cheers,

Simon

[Stu Jackson]

Unscrew the vent, take care to notice which position the little rubber stopper thingie is in, clean it and replace it.  While you're at it, check the other vented loops, which may be between the your head pump and bowl, and the two others:  on the water line inlet to the exhaust riser and the shower sump to the diaphragm pump.

[TonyP]

Simon
I would say no as the loop is higher than the tank. Though to be sure, empty the tank first then check the valve and clean it.
I cant say I have ever heard it on our boat.
Tony

[Ron Hill]

Simon : As Stu said you have a problem with the valve in the vented loop.  I believe that you can get a new valve from Forspar!?!

[lazybone]

It probably just has a bit of ...."food" lodged above the rubber valve.

[Ron Hill]

Simon : I might add that air is supposed to be sucked in so the syphon is broken.
 
You might also need to check the "out" hose on the way to the holding tank -- because to have "bubbling" coming from that valve indicates to me that the flow on the OUT hose side is probably restricted to almost clogged!!

A thought

[simdim]

Folks,
Thank you for all ideas. I took a top cap apart and cleaned the rubber valve. That did not fix the bubbling but made it worth.... next step to get new valve and see.

Cheers,

Simon