Black Water Flush

[bigbird272]

Every time I flush my black water tank the hose connection leaks and water goes behind the docking station. I do not use a pressure regulator to flush the back water tank. Should I ? The hose connection is tight. It appears to be coming from below the connection to the at the docking station and dripping behind. I believe I read of someone caulking the connection behind the docking station? Any suggestions would be appreciated. The plastic connection for the city water has been replaced with a brass one after a minor modification. Perhaps I should do this with the black water flush as well.

Rick

 

[2010augusta]

I would make sure that the PEX connection is tight on the back side of the UDC, and consider trying a different washer in the hose connection.

Another thought would be to change the end of the hose for a plastic end and try to get it to seat tighter.

Putting a brass inlet would help to, there is just something about trying to get plastic and metal to seal, I have always had better luck with plastic to plastic and brass to brass.

 

[Ray LeTourneau]

Rick, behind the wall of the docking center there should be a connection that may be leaking. It is a compression type connection that should be checked. Your trailer has this type of connection at all fixtures. Caulking a hose connection is never a good idea. These types of connections in our rigs don't use that.

 

[ChopperBill]

The consensus is to use a pressure regulator even on the black flush.

 

[mikeandconnie]

My did the same thing, I had to put 2 washers in the connector and tighen it down hard.. it be working a couple weeks now with out leaking. When I get my rig home someday my first project will be changing out all the plastic conectors.

 

[lmcclure]

I agree plastic to plastic and brass to brass. That being said I use an adjustable pressure regulator with a 4 hose connection manifold. I use the Sewer Solutions drain and use a gray hose on it, I then use a gray hose on the flush system, I also use a white hose for the rest of the water. This leaves me a 4th connection for whatever ails you.

 

[JohnDar]

My plastic tank flush fitting broke on the outer side of the UDC, so I replaced it with a brass city water inlet, complete with check valve. Remove the three screws on the outer flange, toss the piece of junk, insert new fitting with it's own flange, attach using the three screws you pulled out. The PEX fitting that attached to the backside of the plastic one fits perfectly.

 

[bigbird272]

My plastic tank flush fitting broke on the outer side of the UDC, so I replaced it with a brass city water inlet, complete with check valve. Remove the three screws on the outer flange, toss the piece of junk, insert new fitting with it's own flange, attach using the three screws you pulled out. The PEX fitting that attached to the backside of the plastic one fits perfectly.

I think that is the best bet. I hate plastic. So on Tuesday I will go get another connection. First I will take it out and see if it is loose. I did that with my city water connection as well.

 

[Bobby A]

all my plastic fitting leaked behind the UDC from day one, I took them all out, replaced them and gooped the treads with plummers puddy and put them back together, haven't had a problem since. Might not be the correct method but it worked.

 

[ChopperBill]

I was doing my inspection yesterday on the new unit and there is no check valve in the black flush. When I disconnected hose water drained out of the connection. The way I figure it, isn't keeping drain back out of the water system is what the vacuum breaker installed is for? I see no need for the check valve unless the vacuum breaker has been removed.

 

[Rickhansen]

On our 3670 any leaks (fresh water, spills from the gravity feed to the fresh water tank, or black tank flush) in the UDC was ending up as a puddle behind the utility wall in the basement and ran under the wall into the basement. The hose-entry screw cap prevents the UDC from draining as it should. I caulked every penetration in the UDC back wall and drilled 4) 3/8" drain holes in the floor of the UDC. I took 1/4" flexible tubing coated the outside with silicone caulk and slid into the 4 holes. Once the silicone dried, I trimmed each tube flush with the UDC floor panel. If I had to do it again, I'd have upsized the tubing a bit. I also bought a 2" thick sponge, made a 1" hole in it with a slit to one edge, and cut to size to fit snugly in the hose entry port to keep critters out. Works well.

 

[JohnDar]

The check valve came as part of the city water inlet I replaced the tank flush fitting with. Granted, it's not really necessary for the tank flush, but it's there. Easy enough to drain it by pressing the tab inside and dumping it into a small container. Could even remove it, entirely. There was no specific tank flush UDC fitting available when I bought it. At best, the original plastic fitting is a flow restriction since there is a reduction of diameter in the middle of it, from 1/2" down to 3/8". The vacuum breaker up in the wall prevents nasty in the tank from backflowing out the UDC, should you fill the tank to the point that you're sitting in it on the commode. The water that flows out when you remove the hose is what didn't make it past the breaker when you shut off the water. Maybe 8 or 10 feet of 1/2" PEX worth of water.