Sani Flush........doesn't

tgreening

Active Member
Went out this past weekend for our 4th trip in a 2011 Cyclone 3950 and finally got around to giving that black tank flush system a go. I drained all my tanks like normal and then hooked up the water supply line to the flush fitting. I verified the tank drain valve was open, and then cracked open the supply water. I have a clear elbow at the drain pipe so I can keep an eye on what's coming out, but nothing appeared to be coming out. A quick glance showed water coming out of where all hookups are, and water in my storage compartment.

I pulled off the access panel inside the storage bay that would allow me to view the backside of all the hookups, hooked up water again, and got water spraying out the front of the sani flush connection as well as the back of the connection (usually not visible because it's behind the access panel).

Next thing I did was disconnect the campers water line from the back of the sani flush connection, which is pretty much just a check valve (functioning as best I can tell) and try to blow through the line. It was fairly hard to blow through and I could tell that there was water in the line and the far end felt like it was submerged. That didn't make sense to me since the black tank had been emptied, and I would have thought the nozzle end of the flush system would be positioned quite high in the tank. I called it quits at that point and headed for home.

Once back home I tried blowing through that line again and now it's plugged solid. I can't blow a bit of air through it. None.I'm fairly certain the reason I was spraying water everywhere was because this line was/is somehow restricted and that water pressure had to go somewhere. I opened up every spigot in the place and got nowhere as far as being able to blow air through the line.

I called Heartland customer service and whoever I spoke to seemed to think I needed a new check valve but unless there is more than one check valve I'm not convinced. He didn't seem to be grasping that I could remove the check valve from the equation and simply could not force any air through the line.

Hopefully I've been clear enough in my description. Anybody that could shed any insight on the system and how I might trouble-shoot it myself, please feel free to step in. I called my dealer who was supposed to have one of their techs give me a call, but par for the course I received no call back. Since getting anything done there seems to require the standard Month of Sundays I'd just as soon avoid them if possible.
 

hoefler

Well-known member
It should be a check valve/vacuum brake, sounds like it is installed back wards. Look at it closely. There should be an arrow on it. The arrow points toward the tank, not the hose connection.
 

cookie

Administrator
Staff member
There is also an anti-syphon valve in the system. I don't know where it is located in your Cyclone but one common place they are found is behind the access cover located in the shower. Look behind that round cover in the shower. I have heard of that valve being installed backward and this sounds like it may be your problem.
Another way to locate that valve is to follow the water line from the hookup in the UDC. It should go up into a wall somewhere and have a return line located next to it.

Peace
Dave
 

Ray LeTourneau

Senior Member - Past Moderator
tgreening, to add a little to what cookie said, RVIA code ls for the anti-siphon/check valve to be mounted above the highest fixture in the rig. That's why it's up an interior wall somewhere. (usually behind the shower) I don't think there is a check valve behind the UDC wall at that inside connection unless they have changed something over the years. You can call Heartland customer service and have your VIN handy. They should be able to tell you the valve location.
 

tgreening

Active Member
Thanks guys. The info on potential valve location is definitely useful. I'll try to get out there tomorrow, pull that access cover in the shower and see if anything jumps out. If it is in there I sure hope it's accessible without yanking the shower. If that's the case I'll get it reported to the dealer but probably wait till the end of the season to take it in. Last time I had issues, between waiting on parts and then getting it scheduled for repair, way too much down time was involved. Or.....I might schedule a trip over past the factory, stop in and pitch my case, and hopefully get some customer service love. :)
 

rustyshakelford

Well-known member
I thought the black tank flush went from the udc to the nozzle. When looking at the plumbing for ours, I didn't see any other lines from it.

Hope you get it figured out

Brett
 

Ray LeTourneau

Senior Member - Past Moderator
I thought the black tank flush went from the udc to the nozzle. When looking at the plumbing for ours, I didn't see any other lines from it.

Hope you get it figured out

Brett
Brett, the flush line goes from the UDC to an interior wall cavity then up that wall to the check valve. Out of the valve then back down the wall to the black tank.
 

tgreening

Active Member
I followed the line from the UDC and see where it went up the wall in what looked to be the shower area. I pulled the access cover in the shower and found the check valve. I wish I'd had the opportunity at the time to take a picture but maybe I can describe it. The valve has two fittings on it, one short and one long in what could be described as and L shape. In my case the short leg is pointing straight down and has a blue line attached to it. I assume this is the line from the UDC. The long leg points to the left as I'm looking at it and has a red line attached to it. Given this info, is there anyone knowledgeable enough to say this is hooked up correctly and not backwards? I have a replacement on hand to swap in but I want to make sure I put it in correctly.
 

Ray LeTourneau

Senior Member - Past Moderator
I followed the line from the UDC and see where it went up the wall in what looked to be the shower area. I pulled the access cover in the shower and found the check valve. I wish I'd had the opportunity at the time to take a picture but maybe I can describe it. The valve has two fittings on it, one short and one long in what could be described as and L shape. In my case the short leg is pointing straight down and has a blue line attached to it. I assume this is the line from the UDC. The long leg points to the left as I'm looking at it and has a red line attached to it. Given this info, is there anyone knowledgeable enough to say this is hooked up correctly and not backwards? I have a replacement on hand to swap in but I want to make sure I put it in correctly.
Ya got me on this one. I've never had a problem with ours so I haven't had the need to "see" it. I suppose you could just remove it and try blowing through it or adapting a hose to it to see what direction it flows. It may even be marked in & out or have an arrow indicating flow direction if you check with a flashlight??? You could put air in the connection at the UDC to determine which line comes from the UDC. I'm just throwing some ideas at you. Maybe someone else will know the color code.
 

jmgratz

Original Owners Club Member
No Ray cause most of the instruction manuals are very lacking. Seems like those that write them 'assume' too much.
 

Ray LeTourneau

Senior Member - Past Moderator
No Ray cause most of the instruction manuals are very lacking. Seems like those that write them 'assume' too much.
Jim, you took my post too literally. Ya know how most of us try to assemble something or attempt a repair and have all sorts of little problems then all of a sudden it hit's us. Why don't I just read the instructions. Would have been much easier. More logical?

Your post was just that. Logical, something that maybe would have been the easiest thing to do. Call the factory.

I agree though that the owners manual for all RV's, no matter who makes them, is very vague. Almost worthless to a seasoned RVer.
 

tgreening

Active Member
Ray LeTourneau;180848 Your post was just that. Logical said:
Another logical thing to do would have been to read my entire OP, in its entirety. Those that did would have noticed that I did call the factory, and while the rep I spoke to was less than clear or informative, he did actually send the part that I would ultimately need.

:)
 

Ray LeTourneau

Senior Member - Past Moderator
Tom, did you get the problem solved? Was there anything imprinted on the valve for flow direction indication?
 

tgreening

Active Member
Tom, did you get the problem solved? Was there anything imprinted on the valve for flow direction indication?



Yes, problem solved. The valves do have a flow direction arrow, but since there are no docs included with a repalcement valve you have to assume the arrow means direction of flow. Relatively reasonable assumption to make but maybe not so clear for those not mechanically savy. In my case it appears the factory valve was stuck shut. I replaced it and everything seems fine now, though I do have a slight leak at the connection in the UDC. I might have to hit up the factory for a replacement there as well.



For the record the valve is in fact behind the access panel inside the shower. At least on an early 2011 3950 it is. The most difficult part is avoiding cross threading of the connections. Space is tight and the hoses are quite stiff. Cooperation didn't appear to be a priority. :)
 
Top