Re: Black tank mystery
Reply #55 –
Susan,
You'll have to excuse us - we are bad around here about going off on tangents in these threads. Like talking about lubing the dump valve, which is of no help to you at the present time. But we mean well, and a lot of times the digression brings up some very useful info. But to get back to your problem...
Like Chuck (craneman) says, I think your best course of action is to follow the procedure shown in the link below. Looking at your recent photo, I agree with Red Tractor when he said he thinks the electric part of your dump valve has been added on to a standard manual valve. If the metal parts of the valve are unbolted and removed, then I think you will be looking at the same valve as shown in the photo below. The metal rod will probably pull out of the top of the valve when the metal frame is removed, because we think the rod has separated from the sliding gate.
NOTE: I'm still trying to think this through in my head. If you try to remove the metal framework and the steel operating rod does not want to pull easily out of the top of the valve, STOP THERE and get back to us. If that happens it might mean the rod has NOT come loose from the top of the blade, and we will need to reconsider this whole plan.
Once the metal parts are out of the way, the idea of the "fix" is that you (or someone) will carefully cut the top section of the valve off with a saw or a Dremel tool with a cut-off wheel. When the top of the valve is removed, then it should be possible to grab the actual sliding gate with Vice-Grip pliers and carefully pull it up, which will open the valve and let the tank drain. You don't want to pull the gate up too far, or it will come completely out of the valve body resulting in a small geyser. Try to just inch it up slowly until about 1.5" of the blade is exposed. This should open the valve enough to let the tank drain. Looking at the photos in the link will help clarify this explanation.
Waste valve handle and rod pulled out of the valve - Airstream Forums
If you wish to get the tank contents sucked out by a septic tank service truck before attempting this operation, that sure wouldn't hurt anything.
When removing the metal and electric parts of the valve, try to pay attention (make notes) to how it is attached. Once you finally get a new dump valve in place, you will want to reinstall the metal frame to (hopefully) restore the electric valve operation.
Topic: Black tank mystery