Tank flushing questions

I’m unable to get the tank flush feature to work on my new 2552. No problem emptying the tanks — the electrically operated dump valves for the black and gray tanks work just fine, as does the macerator pump. But I can’t get water to flow through the tank flush connection. I connect a hose and open the quarter-turn valve for either the black or gray tank, but no flow. I know this worked in Elkhorn because Earl demonstrated it to me last February.
A placard in the compartment warns me to open the “fullway  termination valve”. I don’t know what or where this is. Most likely that’s my problem.
I’d appreciate any advice from more experienced owners.
Thanks,
John

I’m unable to get the tank flush feature to work on my new 2552. No problem emptying the tanks — the electrically operated dump valves for the black and gray tanks work just fine, as does the macerator pump. But I can’t get water to flow through the tank flush connection. I connect a hose and open the quarter-turn valve for either the black or gray tank, but no flow. I know this worked in Elkhorn because Earl demonstrated it to me last February.
A placard in the compartment warns me to open the “fullway  termination valve”. I don’t know what or where this is. Most likely that’s my problem.
I’d appreciate any advice from more experienced owners.
Thanks,
John

I presume you do have a hose connected to the flush water inlet at the bottom of the control panel for the dump valves and flush quarter turn valves. With the hose attached to a faucet and the faucet turned on.

The city water line (with the 4 way valve) is not used for the tank flush valves.

Yes, I connect the flushing hose (not our fresh water hose) to the female hose connection in the dump compartment. My understanding is that the plumbing goes from there to the quarter-turn valves and then to the cleaning jets in each tank, and nowhere else. So what, I wonder, is the “fullway termination valve” referred to on the warning placard?

You may want to consider a secondary option when boondocking.  Every RVer always
considers the possibility of having to make operational their Plan "B"?

A placard in the compartment warns me to open the “fullway  termination valve”

  The fullway termination valve is the knife valve to drain the tank.  On a PC it is electrically operated and you noted that yours work.  It has nothing to do with the flush system except they want to make sure you open the drain before turning on the flush.  You can imagine what would happen if you turned on the flush without the drain open and walked away................

As to why the flush does not work I am not sure.  It is not a complicated system.  Make sure the hose itself has water flowing through it at pressure.  If that tests good then test the valve in the compartment by loosening a connection after the valve to make sure there is pressure there to eliminate a bad valve.  After that it is just a straight pipe to the tank nozzles.

Thanks for your explanation, jatrax.

The piping  is directly under the inlet and you should be able to see feel if water is flowing.  The only thing blocking flow to the pipe is the valve.

While on a recent trip, I also found I could not flush out the tanks. I pulled the hose bib (where you connect the water hose) and found that there is a check valve in the fitting. It was jammed shut and I could not free it. I found an RV dealer, purchased a new bib, and installed it. Works fine. I beat and pounded on the check valve and never did get it loose up till the time it took a high dive into the campground dumpster.

Thanks Ron-n-Toni. I bet that’s my problem.

Yes, my problem was exactly the same as the one Ron-n-Toni experienced: the check-valve built into the tank flush hose connection was stuck closed. I got a new city water hose connection ($25) from the RV parts store across the street from the RV park we're staying at in Pismo Beach. It was surprisingly easy to install -- I didn't even need to crawl under the rig.
Problem solved. Thanks for the helpful replies.

I have a question for you with the check valve located at the tank flush hose hook-up.  Do you also have turn valves, one for each the gray and the black tank?  Or did Phoenix recently replace the two turn valves with a single check valve at the hose connection?  I ask wondering if we too have a check valve at the hose connection and never realized it.

Ron,

Yes, in our new 2552 the tank flush hose inlet, with its integral check valve, is plumbed to two quarter-turn valves, one for the gray and one for the black tank.
In buying a replacement inlet connection, I noticed that these parts are available both with and without the check-valve. External appearance is the same, but if you remove the mesh screen and compression gasket where the garden hose connects, you can see the check-valve, if there is one, immediately behind the mesh.

John

Ron,

Yes, in our new 2552 the tank flush hose inlet, with its integral check valve, is plumbed to two quarter-turn valves, one for the gray and one for the black tank.
In buying a replacement inlet connection, I noticed that these parts are available both with and without the check-valve. External appearance is the same, but if you remove the mesh screen and compression gasket where the garden hose connects, you can see the check-valve, if there is one, immediately behind the mesh.

John

Very good to know John.  Thanks for the details.  Maybe I have a check valve as well and never realized it.  My rig being 11 years old, some things have changed over the years, but maybe not in this case.