I tried using the black tank flush just once so far and it didn't do a thing.
Background: I first dumped the black, then both greys ... watched it all drain out via. the clear elbow I use. The dumping part went fine. Then I figured I'd use the handy dandy black tank flush flush ( I installed one on my old trailer and it was outstanding -- never had any issues using it, ever).
However, on this recent roadtrip back to Colorado ... all the lousy dump stations I was at always had one of those lousy metal nipples on it (no threads) ... so I got out my old green "water theft" or whatever its called ... and put it over the metal end (other end screws into your flush hose) ... and held onto it ... getting somewhat wet as sometimes happens ... but I felt I had a reasonable ok connectiong ... and of course nothing ever came out the black tank and I did have it open. I waited several minutes and nada.
Anyways, I finally gave up in frustration as the weather wasn't so nice ... and I was getting kind of wet ... and I figured the lack of water pressure (because of the poor connection I had to my hose) was the reason.
I haven't had opportunity to try it since, but has anyone had similar problems with low pressure connections into the black tank flush? Or just had a problem with it working on a brand new unit ?
I've read on other threads that some have a pressure regulator inline. Everything seems pretty well sealed up, so hard to look into, compared to my old trailed which didn't have any sealed belly, so you could see it all.
There is a pressure operated check valve but I have no idea how much pressure it takes to open it. I will say I've been at some dump stations that had flat sorry pressure out of the rinse hose.
Now I have heard about check valves being stuck or connected backwards. I'd connect at home with known good pressure and see what happens. Just run it a minute or two to prove it works, that won't put much of anything in the tank but you'll be able to hear it run.
I would check the vacuum breaker/check valve. Mine was loaded with sawdust. Took it apart, cleaned it out and it worked great. On my first Wildcat, it was located behind a panel in the bedroom, in my current one, it's located underneath the bathroom sink.
Our new 295RSX is back at the dealer with a small handful of issues after the first shakedown cruise. One being, could not get water to come out of the black tank when connected to the flush. The short story is that the dealer's techs found the line behind the flush connection kinked, so only a trickle of water was going thru. They had to access it thru the floor underneath.
This is our 4th FR camper and we have generally been pleased with the performance of each one. However, I've learned to accept that this industry's focus on quality control is minimal at the factory. The dealer's PDI is only marginally better. Note to first time buyers: make no assumptions, test every system before you leave the dealership.
First off the (Water Thief) as you found out will (Leak,Spray,or Blow Off) if trying to use (Dead Headed/Restricted)! It was a Good thing that the PSI was low on your attempt to use. Backflow valve,kinked hose,or clogged spray nozzle is one of the (3) areas I would check. Youroo!!
Located the water pump, heater connections, various valves, fittings, etc., in the area behind all the water connections panel in the storage basement. Very accessible if needed. Things are looking up !
when I tried to use mine the first time it would fill the fresh water tank, took to dealer and they plumbed it the correct way, my backflow preventer is in the master bathroom in the wall under a removal panel