Finally screwed up after 19 years of using flush king.

[quick83]

Just wondering what others know or think. I charged the flush king with BOTH the Rv valve AND the flush king valve closed and the dump station pressure was 60 or more psi. I saw Water coming out around the flush king outside of valve and hurried to turn off water and right then I heard a small (not loud) pop inside behind the dock station. On my unit the 1.5” pipe from grey also connects to the 4-5” main drain. I’m pretty sure the valve that took the hit was the grey due to its small size. Hope not a cracked pvc pipe[emoji849]. I’m going to remove underbelly and inspect all. It suppose to rain forever so i guess I’ll just get wet to help with my anxiety. I’ll fill both tanks and hope no leak with NO pressure. What you think? I wonder if 70 psi would crack a pipe? Thanks for any advise or info in advance.

[Bama Rambler]

Waste piping, valves and fittings aren't pressure rated. They're only tested to about 10 ft WC which is about 5 psig.

I'd suspect the larger 3" waste valve failed before I'd suspect the smaller 1½" valve due to surface area. The blades are the same thickness so the 3" would have more surface area of the thin blade exposed to the high pressure without support than the smaller blade would.

Now, having said that, there's really no telling what 'popped' it could be anything from one of the valves, to a piece of piping, to one of the fittings, to just a joint that wasn't glued well.

Hopefully it'll be something easy to get to and to fix.

[racer4]

OP quote: "... I charged the flush king with BOTH the Rv valve AND the flush king valve closed"


This caught my eye. Are you saying the black tank dump valve and grey tank(s) dump valve was closed when water was turned on to the Flush King? Maybe I am misunderstanding.

[quick83]

The grey was shut also.
Just got done opening the underbelly around the connections I was very surprised to find the valve assemblies are right there that was pretty nice did not have to remove my whole underbelly to get to it I just made flaps to get in there. I filled both tanks and waited and inspected all around the valve flanges both grey and black and waiting for leaks and see absolutely nothing. Thank God. I wonder if it’s possible with enough pressure for the valve to just leak around the edges with the sudden pop like that and not ruin it because it still doesn’t seem to be leaking by when I close it either, I guess time will tell if I have a slow leak from one of the valve gaskets. Again I’m so happy i absolutely see no leaks anywhere or water anywhere in the underbelly. I also checked all pvc for leaks and none I can see. I did take down one side so I could look in there and I put my arm and hands inside and there’s no water. Thanks for helping. Any other thoughts.

[Bob_K]

Did the water pressure perhaps push the Flush King off one of the tits on your outlet pipe?

[chaps2018]

I did this once. Water pouring out of the underbelly.

I did the same thing you did. Open the underbelly inspect, test the valves all ok. I had to replace the insulation under the black tank as it was soaked.

Never had any issues with leaks etc for the next 5 yrs

[quick83]

Originally Posted by chaps2018

I did this once. Water pouring out of the underbelly.

I did the same thing you did. Open the underbelly inspect, test the valves all ok. I had to replace the insulation under the black tank as it was soaked.

Never had any issues with leaks etc for the next 5 yrs

Wow. So it’s prob possible the valve and or packing can leak buy under pressure and then be ok. I bet if we did again by accident it may be worse second time. I was able to get my hands and socket on the 4 fasteners holding both valves together and they DID take a few turns before they were German (good n tite). 😬. Also flush king took some tightening. Thanks for everyone’s advise.

[quick83]

No the flush king was fine. Thanks.

[quick83]

So I guess it’s really possible since I saw NO water anywhere and filled tanks and waited 3 hours and saw no leaks from Valves, tanks and pipes I may be ok. Did I miss inspecting anything? Thanks again for all the help.

[Bama Rambler]

Glad it didn't break anything. The popping you heard could have been a seal relieving and when you took the pressure off it, it went back in place. At least that's what I choose to believe!

[Mike ONeill]

Could have been back flow device or tank expanding

[Paulie1138]

Just curious, would not any pressure generated be relieved via the tank vents? If overfilled, would the water come up the drains or out the top of the vent on the roof?

[B and B]

What about your auto vent for the Grey Tank under your sinks? Maybe they popped.

[Mark Ulmer]

I always use a pressure regulator and I put my Y-valve after it, so it affects both city water hose as well as tank flush hose. Might take a little longer to flush your tanks with the Flush King that way, but hopefully helps to avoid problems...

[Bama Rambler]

The pressure never got to the tanks or vents. It was trapped between the gray and black termination valves and the flush king termination valve since he had all of them closed. So it had to be something in that small section of plumbing that relieved.

[DBigbee]

Love that Flush King!