Grey/Black water tank problem

[steveandrew1000]

Hi... I have bought a used 2006 GST280 in the UK and seem to have a problem with the tanks. The illuminated gauge is displaying the black water tank as full and the grey water tank as 3/4 full, but you can leave both valves open and nothing will come out of either tank unless you start running some water inside the trailer from the taps and this stops as soon as you turn the water off? If you run the water in the toilet it just fills the compartment under the bowl.
I am worried that there is some sort of valve problem and would like to know if it is possible to gain access to it? I have been through the manual, but it explains nothing about this kind of situation.
Any help is appreciated, thanks.

[aintgotnun]

Welcome to FRF.

The problem you are describing is not uncommon. There is nothing wrong with your tanks or valves. You just have buildup on the sensors. There are many opinions on how to clean them but bottom line they all involve water.

The next time you go camping get a site with sewar hookups or if you have a place where you store your rig use that. Fill and dump your tanks. A lot. Filling and dumping "should" clean them off. It may take several fills and dumps to do this. Other than that it's no major issue.

[Hokiehall]

There have been suggestions of putting ice cubes in the tanks and then taking the trailer out for a few miles to slosh them around to clean the sensors. Not sure if this works but it is a suggestion.

[steveandrew1000]

Thanks for the help and the welcome to the forum...in the process of cleaning the grey tank through...still have the problem with the toilet though....it will fill completely with fresh water, bowl and pedestal, but will not drain away at all into the black tank??? Would it have something to do with the flange seal as this seems to be closed??

[aintgotnun]

Originally Posted by steveandrew1000

Thanks for the help and the welcome to the forum...in the process of cleaning the grey tank through...still have the problem with the toilet though....it will fill completely with fresh water, bowl and pedestal, but will not drain away at all into the black tank??? Would it have something to do with the flange seal as this seems to be closed??

guess I didn't read that part right. yeah that does sound like a problem.. as soon as you move the "flush" lever it should open up the vlavel and gravity should do it's thing and pull the water/waste down into the tank. is that valve not opening up? can you maybe post a pic of what you are seeing? that might give us a better idea of what's going on.

greg

[retired2]

If you have a curved pipe from the toilet bowl to the black water tank, you may have a paper buildup in the curve. That will probably tale a flex wand tobe inserted and "roto root" the paper out. May have to go slow at first as the paper is going to hold the water and not allow it to go to black tank very quickly.

[08flagvlite]

Sometimes the sensors inside of the tanks that sense something in there, get covered up with toilet paper or other debris; that will give you a false reading. I would fill the tanks until you know they are full with fresh water, and then drive the trailer to a local campground with a dump station hookup. Drain the tank,(you will hear and feel the weight of the water draining through the pipe into their tank. Then check your sensors to verify they are empty. As a helpful hint, I put 2 capfuls of Calgon water softener liquid- available at most any grocery store for laundry- to help make the inside of the tank "slick", therefore nothing sticks to it. Also helps to cut down foul odors, too.
Hope this helps you! Randy