Black Water Flush Blocked

[ElliotA]

I just picked up a 2006 28' Safari that had basically never been used. The owner lived in it for three months while she built a house and after that it had been sitting in a field for over 4 year.

When I first took it out I found that the black water tank discharge was clogged with toilet paper and I used a flush adapter on my sewer hose and a hose wand to wash it all loose. I assume she never used chemicals and used regular toilet paper.

Everything seems to work right now except that there is a blockage in the built in black water flush system. When I connect a hose to it no water goes into the black water tank and all I get is an overflow around the skid plate protecting the black water tank. I checked inside the bathroom where you can see the plumbing for this system and there are no leaks there.

Is there a valve or something that needs to be opened? Remember this trailer has almost never been used and for sure the black water flush had never been used.

Elliot

[dznf0g]

I sounds to me like there is a leak where the BW flush line enters the black tank. If that's the case, it will involve some disassembly to get to it. I am not sure of your unit's setup, but on mine, I believe I would have to drop the tank pan and tank. Or, at least CUT an access into the pan.

I would tell you to just forget using the flush system, (many seem to think it is ineffectual at best anyway) except if you do have a leak there, I believe you will leak black water into the pan whenever the level is as high as the flush head. That could be NASTY!

[Silver Goose]

Look for this valve. I found this under the closet on my 27FB. It may be elsewhere in different floorplans. It could be anywhere in the line between your BW flush connector and the tank sprayer and should be in some accessible location (under sink?). Mine was secured too tightly to the wall from the factory and was cracked allowing water to run out under the belly when I tried to use it.

If you can get a visual on the valve, have your helper turn on the water. The water pressure moves the piston to the upper position, applying pressure to the ball/spring valve and then passing on to the sprayer. The ball valve is supposed to prevent back flow and when pressure is removed, the piston drops to the lower position allowing the input line to self drain.

By observing this valve, you should be able to determine if it or its connections are the problem or if the leak is beyond at the much less accessible sprayer head.

[dznf0g]

Originally Posted by YankeeDoodle

Look for this valve. I found this under the closet on my 27FB. It may be elsewhere in different floorplans. It could be anywhere in the line between your BW flush connector and the tank sprayer and should be in some accessible location (under sink?). Mine was secured too tightly to the wall from the factory and was cracked allowing water to run out under the belly when I tried to use it.

If you can get a visual on the valve, have your helper turn on the water. The water pressure moves the piston to the upper position, applying pressure to the ball/spring valve and then passing on to the sprayer. The ball valve is supposed to prevent back flow and when pressure is removed, the piston drops to the lower position allowing the input line to self drain.

By observing this valve, you should be able to determine if it or its connections are the problem or if the leak is beyond at the much less accessible sprayer head.

Although the layout may vary between floorplans, my airbreak also leaked, but it showed as dripping at the joint between the belly pan and the rolled gray sheet (at the frame) as well as through the city water access compartment, outboard and rearward of the tank pan. I had no dripping at the pan

[ElliotA]

I checked the airbreak valve as suggested and it seems to work OK and is not leaking. I guess there is a breakage where the line enters the tank.

Is this something that could have happened due to freezing weather? I had to replace the Thetford toilet valve as it was cracked and leaking due to not being drained and freezing.

[dznf0g]

Probably not, unless the black tank was significantly full during the freeze. I suspect just a bad fitting of the spray head into the tank.