Flush for blacktank

[dreafsnyder]

I purchased a 2020 cougar 5th wheel model 32 BHS and when I hook up hose to flush nothing happens. I'm new to this type flush, but don't see any handles or ways to open.

[Martian]

There usually is no valve besides the anti backflow valve. Do you hear water running through the hose or do you see water running into the tank when you look down the toilet? The best way to tell if you have flow is open the black drain. Be careful when you use it as the tank can become pressurized so never leave it alone and flushing.

[dreafsnyder]

No water flushing thru at all.

[chuckster57]

Welcome to the forum

Odds are the anti siphon valve is installed backwards, more common than you think. It’s probably under the sink in the bathroom, or behind the shower wall.

Best way to test is to remove the pex lines and note which line is connected to which port on the valve. The valve will have an arrow indicating the direction of flow, and LOW pressure air at the hose hook up will verify the direction of flow and no kink.

If it’s hooked up correctly, then I would contact the selling dealer and schedule a warranty service.

[NH_Bulldog]

Since it is a 2020, and you don't know if it ever worked for the previous owner, there could be a few issues. As others have noted, the anti-siphon valve could be backwards, or stuck closed from lack of use, or just plain capped off because it failed/leaked at some point in the past. Another possibility is that the spray head in the tank has filled with...let's call it crud, and is blocked and useless.

[GlasNav]

Odds are it is the anti-siphon valve installed backwards. Ours was, and the numerous posts I've seen on this forum regarding the same issue leads me to go in that direction first.

Leaking, or blanked off doesn't sound good!

[markdol1]

Ok folks ,place your bets on the under sink valve I had same problem on my 2014 bullet. I dont think i know of anyone whom had this valve that worked right!

[jxnbbl]

Crimped pex plumping here! - that had to be cut and elbow put in place.

[NH_Bulldog]

Mine ceased working and I cut it out and direct-piped. Now I use a anti-siphon hose fitting

[CBears]

After reading all the horror stories about the plastic POS anti-vacuum under the sink, I replaced mine with brass followed by a brass inline anti-backflow. Haven't even been out camping in it yet. Threw the brand new plastic one it came with away.

[sourdough]

Originally Posted by CBears

After reading all the horror stories about the plastic POS anti-vacuum under the sink, I replaced mine with brass followed by a brass inline anti-backflow. Haven't even been out camping in it yet. Threw the brand new plastic one it came with away.

LOL! I have the one from my previous '14 trailer sitting on a top shelf of a shelving unit at the RV barn. I look at it occasionally as I try to decide what terrible end I'm going to give it. Took that RV out on it's maiden voyage about 10 miles from the dealer. On departure morning I was going to do a black tank flush, hooked up the trailer end and had DW turn on the water. The anti siphon was bad (brand new) and soaked me when it wouldn't pass water (and obviously I didn't have the connection tight). It was in the 20s IIRC and thought I was going to freeze. I haven't forgiven it so sentencing has not been passed - yet.

[CBears]

Originally Posted by sourdough

LOL! I have the one from my previous '14 trailer sitting on a top shelf of a shelving unit at the RV barn. I look at it occasionally as I try to decide what terrible end I'm going to give it. Took that RV out on it's maiden voyage about 10 miles from the dealer. On departure morning I was going to do a black tank flush, hooked up the trailer end and had DW turn on the water. The anti siphon was bad (brand new) and soaked me when it wouldn't pass water (and obviously I didn't have the connection tight). It was in the 20s IIRC and thought I was going to freeze. I haven't forgiven it so sentencing has not been passed - yet.

Hahaha, funny, not funny. Great story though!!

[rlh1957]

Ours was installed backwards from factory. Turned around and wasn’t pleased with the water pressure or flow so I took it out and tied the lines together. Works great now. All it does is adds water back to the tank faster than toilet flush. There isn’t enough water pressure to wash anything down.