Black tank flush -- water will not enter

[zank]

On new Interstate EXT, after draining black & grey tanks, hook hose up to black tank flush, turn on hose and nothing happens. Any ideas? Behaves as if it's 'corked' on the inside. Could there be step missed by manufacturing/assembly where valve 'knock out' was not?

[HowieE]

I realize that if you bought it you would want it to work. However the flushing of a black water tank is a complete waste of time and water.

If you want to flush the black water tank in a much more effective way try this. drain the black tank. While the valve is open lift the drain hose just above the height of the tanks and open the gray tank. Count to 10 and close the gray valve and drop the hose. That will put Gallons of water into the black tank. Let that drain close the black tank and then drain the gray.

[cwf]

I use my "black tank flush" On our 1999. I use it to add Water to the tank to flush again then add water for the trip home and storage .. (Our Part of Texas stays above freezing most of the year).

I would have dealer resolve.

[cwbiii]

There is a back-flow valve that is probably stuck or there is another valve you have to open to initiate the flush. Generally there is not a direct connection to the tank simply by screwing a hose into the inlet. Flushing with this is dependent on how well built the flushing system was built. Most are not well built but are simply a spray nozzle inside which haphazardly squirts water around not achieving much in the way of cleaning. I would generally flush my tanks several times when I got home to have them ready for the next outing.
One trick is to partially fill and drop a bag of ice cubes into the tank before you start down the road... the abrasive nature of the ice sloshing around does a very good job of loosening up crud in there. You want to dump when you arrive where you are going so that it does not have a chance to settle or re-goo.

Chuck

[UKDUDE]

Originally Posted by HowieE

I realize that if you bought it you would want it to work. However the flushing of a black water tank is a complete waste of time and water.

If you want to flush the black water tank in a much more effective way try this. drain the black tank. While the valve is open lift the drain hose just above the height of the tanks and open the gray tank. Count to 10 and close the gray valve and drop the hose. That will put Gallons of water into the black tank. Let that drain close the black tank and then drain the gray.

Nope - the original poster has an Interstate with a macerator pump; and flushing the blank tank periodically is very important to ensure the macerator doesn't get clogged, and to keep the electric valves free from anything that will prevent opening and closing.
The black tank needs to be more or less full and with lots of liquid to ensure a good flow will evacuate the contents.
I've never heard of the black flush not filling from a hose. Suggest you ask the dealer to look at it; quite likely a fitting error as you suggest.

[Norrie46]

Take it straight back to the dealer. I had the same problem

[zank]

what did dealer say problem was?

[Norrie46]

There is a back flow preventer/check valve on the inlet inside the trailer. You should be able to see it on the water line inside the bathroom cabinet if we have similar arrangements. According to them, the valve stuck, which can happen. They said they cleaned the spray pipe but could not describe what exactly was done so I am skeptical about that. We have now been on the road five months since then and no problems so far

Norrie

[Protagonist]

Originally Posted by zank

On new Interstate EXT, after draining black & grey tanks, hook hose up to black tank flush, turn on hose and nothing happens. Any ideas? Behaves as if it's 'corked' on the inside. Could there be step missed by manufacturing/assembly where valve 'knock out' was not?

There was one Interstate owner here on the Forums a couple of years ago who had a similar problem. Turned out his backflow preventer (check valve) was installed backwards. Removed it, reversed it, reinstalled it, and all was well.

[zank]

Resolved: Water feed to check valve was installed backwards, i.e. input was connected to output side and vice versa. Major pain since it's behind freezer which had to be removed; after removing door, hinges and two power supply lines. Found this is not something routinely checked at dealer. This along with 10 other items was resolved during first return for warranty items. Where/what is QC @ Jackson Center?

[mythbuster88]

We have the same problem on our new 2016 International.
No flow at all. This was discovered a few days ago after we left the dealer in New Jersey.

I looked and it is hard to get at.

[mythbuster88]

Check valve in backwards. Its the grey thing after the brass gizmo.