Tank Venting

Discussion in 'General RVing' started by Steve H, Aug 19, 2008.

  1. Steve H

    Steve H Senior Member

    Last weekend my Grey Tank began talking to me when I was draining it. Started gurgling and shaking and making all sorts of noise. This is a new problem...has worked fine for two years!

    I looked at the vent pipe on the roof. Appeared OK...stuck a tape measure down the tube it did bottom out but came out dry. Felt like there might be a screen or something at the bottom. The Galley tank also had the screen or whatever at the bottom but it works fine. Left the Black tank alone!

    Can I shoot water down this vent tube with a hose and not have to worry about flooding my 5ver?

    Any other ideas?
  2. Kirk

    Kirk Senior Member

    Re: Tank Venting

    Did you check to see if the vent pipe has slipped down into the tank? If that happens it could be covered by the water in the tank before the tank is filled. You could run water into it to see if it is open, but use care. Another possible reason is that your drain line vacuum breaker may be stuck shut. Does this problem happen with all sinks or only one? what of the tub? There are separate vacuum breakers for the kitchen and the bathroom sinks in most RVs.

    The tape cold be hitting an elbow in the line as vents do sometimes have a 90 degree bend in them. Did you check to see if the vents are directly above the tanks and check the distance to them so that the measured distance may tell you where you hit this stop? It is possible that something has plugged them, but that is not common.
  3. Steve H

    Steve H Senior Member

    Re: Tank Venting

    Hello Kirk!

    The problem only occurs with the grey tank. The galley and black work fine when I drain them. All sinks, tub etc. drain fine. Only when I empty the grey tank do I get the noises and then only after it's about half empty!

    Can you give me additional info on the vacuum breaker? I am not familiar with that part.


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