Draining fresh water tank after sanitizing

[VillageIdiot]

Howdy. Newbie here. I sanitized the fresh water tank in my recently purchased ‘05 2720QB. To drain the fresh tank, does the pump need to be running? That’s the only way I can empty it, so I can flush the treated water out. Thank you in advance.

Kelly

[commodor47]

You should have two drain down valves in front of the street side tire. One valve is for draining the water heater and the second is the fresh water tank drain.

Dick

[VillageIdiot]

Yes sir. I have those two valves in that location. My question is, using the white tank valve, my tank won’t drain unless the pump is running. I am pumping the tank empty because the water exiting the white valve is pressurized. Maybe my shurflo pump has a one way check valve. I’m not sure.

[Kidkraz]

You don't need to run the pump to drain the fresh water tank. In the picture, the light blue nut on the tank is the drain line for the tank. It come off the tank and goes directly down thru the floor.
You open the tank drain line outside and it will empty. Now it won't be completely empty, the drain line is up about an inch. I'd refill the tank and drain it a few times to make sure its clean water.

[Wavery]

Try removing the tank fill cap. You may have a vacuum lock. If no air can get in the tank, no water will come out.

[commodor47]

Originally Posted by VillageIdiot

Yes sir. I have those two valves in that location. My question is, using the white tank valve, my tank won’t drain unless the pump is running. I am pumping the tank empty because the water exiting the white valve is pressurized. Maybe my shurflo pump has a one way check valve. I’m not sure.

Check the drain down valve outlet for blockage. I've had mud daubers plug up one of my valves and they do a nice job at blocking water flow.

Dick

[VillageIdiot]

Nothing comes out of the drain until I turn the pump on. It pumps the tank empty, water flows hard out of white valve. Turn pump off and water stops coming out of tank drain valve. Im sure I know what valve the tank drains from. There’s two valves directly under the tank between wheel and tongue. One white plastic, ball valve, one quarter turn. One brass one, quarter turn with oval handle. There must be something clogging that opening to the valve. Pump on, tank will pump/drain until 1” water left. Pump off = nothing. Trailer sat for I don’t know how long. But gravity drain doesn’t happen. Also all three brass valves under trailer drip, one steady. I’m trying to go camping. I’m going to put some tubing tween the two in the back on the barbs with hose clamps. Let them fight each other. Tubing and second barb with hose clamps and NPT cap on second barb to stop leak on valve next to white valve. These leakers are independent of my drain issue. I’ve pumped it down 3 times to flush the fresh tank. This is just weird that it doesn’t drain by gravity. It sat all night with that white valve open. Only water out of tank was Durr to other three valves leaking. I’m not letting this tank drain issue stop me from camping. By the way, no hose bib at my Doheny Beach campground. Only non-potable at the dump station. Do you guys travel with main tank & toilet full? Or do you fill tank using bladder and funnel after setting up? Thank you

[VillageIdiot]

And my cap is off on the gravity inlet and I’ve tried this drain issue with sink valves open or closed too. Weird stuff.

Kelly

[Kidkraz]

That is odd. Can you post a picture of the tank where the drains come off of it. The pump should pull the water, not pressurize the tank.

[Shane826]

What you’re doing is pumping water into the plumbing and out the plumbing drain. There should be a non-rigid hose with a valve, that’s the fresh tank drain. Open that valve and if nothing still comes out, it’s clogged. Cut a coat hanger and fish it up in the drain line. Something has to be blocking the drain.