UDC black Tank Flush question?

Pappy

Member
During our walk through for our 2013 BC 3250 the technician reviewed all the items and their operation in the UDC. He related that you can use the fresh water hose for the black tank flush in the UDC as well. He stated there is a feature that stops back flow. He said we can just disconnect from the Fresh water connection in the UDC and connect to the black tank flush. I do not feel comfortable with this and wanted to see if that is correct....any input would be helpful. Thank you...
 

JohnDar

Prolifically Gabby Member
SUPPOSEDLY, there is a back flow preventer in the B&B Molders plastic fitting behind the UDC. When the hose connection on mine broke and I disassembled it, all that I found was a hollow black plastic tube that looked more like a flow restrictor than a back flow preventor. I replaced it with a brass city water connection with a real back flow preventer in it.

Now, there is an anti-siphon valve installed in the line, usually stuck up behind a wall or the round access port in the shower stall, depending on the floorplan and who did the install. So, with my fix, I've got two lines of defense against sewer cooties getting into the fresh water lines. But I have a home-made manifold with a line that feeds the black flush, so I don't have to disconnect/reconnect hoses.
 

cookie

Administrator
Staff member
He is correct in that there is a backflow preventer in line.
I would feel ok by using the fresh water hose on the flush line.
However, I use a brass Y at the RV park water supply, and use a seperate hose for my black tank rinse.
I do this because I fill the toilet bowl with water and flush a couple of times while I rinse the tank.

Peace
Dave
 

donr827

Well-known member
I have always used two separate hoses. May not be necessary but I feel better about using two hoses. My fresh water hoses are white and the non fresh water hoses are gray and are kept in separate containers.
Don
 

hoefler

Well-known member
I use seperate hoses also. When at a dump station, you never know who or what has contaminated the spigot there.
 

danemayer

Well-known member
I have city water coming to a 4-way manifold, with 1 of the outputs going to the black tank flush connector. I also have an extra checkvalve in-between the manifold and flush connector to provide a 2nd layer of insurance.

I carry a 2nd hose to attach directly to the black tank flush connector when occasionally using dump stations.
 
We use a 4 way manifold and separate hoses for each connection. The tank flush now has a 45 degree brass valve installed in the UDC so that it won't be confused with the fresh water (which has happened in several threads on the forum) and can be closed just in case the valve at the manifold is ever opened inadvertently. One thing you should abide by is that the fresh water hose never be used for anything else.
 

wdk450

Well-known member
Make your own decision on how many hoses to use, but you can feel safe in that:
1) This is a SPRAYER spraying pressurized clean water into the spaces of your black tank with a big air gap. It's like spraying a fresh water spray into your sewage drain hoses with a physical air seperation.
2) There is by plumbing codes a backflow check valve in the supply tubing of the black tank flusher. This valve prevents any possible (?) backflow from the black tank to the water connection. The OEM plastic check valve has a bad history of blowing apart under high water pressures, and while causing no sewage contamination, the broken plumbing floods the service areas of the trailer, and many times ruins the 12 volt charger/convertor at a $200 replacement cost. Having experienced this on the road, this is something I would like Heartland and their vendors to improve with a brass check valve on the PEX water lines on the tank flusher (and I think that all current owners should upgrade, so this disaster doesn't happen to them on the road).
 

danemayer

Well-known member
I would like Heartland and their vendors to improve with a brass check valve on the PEX water lines on the tank flusher
Bill, there was another discussion about the water heater check valve where someone pointed out that the brass valves contain a very small amount of lead from the manufacturing process and because of that they do not meet California code requirements. I don't mean to start a debate about whether the California Code applies to the flush line; just wanted to point out that sometimes there are reasons why things are done a particular way.
 

Hastey

Oklahoma Chapter Leaders
I would like Heartland and their vendors to improve with a brass check valve on the PEX water lines on the tank flusher (and I think that all current owners should upgrade, so this disaster doesn't happen to them on the road).

This is what I used when I built my manifold and filter system. The one in the picture is 3/4 with 3/4 PEX adapters but you can get 1/2 PEX adapters but that's all I had for the photo.

In addition, I would like to see them stop using the black plastic 90's and T's as well. Spend just a little more and use brass.

checkvalve.jpg
 

wdk450

Well-known member
Bill, there was another discussion about the water heater check valve where someone pointed out that the brass valves contain a very small amount of lead from the manufacturing process and because of that they do not meet California code requirements. I don't mean to start a debate about whether the California Code applies to the flush line; just wanted to point out that sometimes there are reasons why things are done a particular way.

Are we worried about a SLIGHT amount of lead being introduced into the sewage???
 
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