Black tank flush

[davidjsimons]

My black tank flush appears as though it is not allowing the water to pass through and spin the nozzle inside the black tank. Can I hook an air compressor to the flush and try to blow it out or is this asking for another problem?

[JRTJH]

If you do hook anything more than about 40 PSI to it, make sure you remove the antisiphon valve. You'll blow the top off that cheap plastic "gizmo" with compressed air. And, you may possibly blow the "spinning thingey" off the other end if you get too much pressure to it.

Have you considered getting under your sink, removing the antisiphon valve, pouring a little simple green or dawn down the hose? Chances are that over the winter, some crud dried around the tank outlet and if you can get it softened up, it may start working again.

I'd be careful about overpressurizing that system, the weakest link will make a mess under your sink......

Good Luck

[davidjsimons]

Thanks John, I will give that a try.

[CPE]

My5th wheel Sundance had the same problem; anti-syphon was installed backwards in spray flush line from factory.

[davidjsimons]

It worked fine all of last year. I removed the valve. The blockage is in the line to the spinner in the tank.

[Roller4Tan]

try running hot water thru the line from your outdoor shower.

[davidjsimons]

I may give that a try today. Thanks for the suggestion.

[gammb]

2005 Raptor RP3310. There seems to be a 6" cavity between aft bulkhead (with access-panel removed) of the basement and the fwd bulkhead beneath the kitchen sink. The hose from the exterior "Sewer Flush Connection" goes into that bulkhead and I know not whence, from there. The Port Forward (street-side) corner beneath the sink is consumed by the water heater and I'd have to pull that to get to the forward bulkhead beneath the sink.
Surely, there is some way to get to this valve, and the eventual connection to the black tank, without gutting the interior.

Thanks for any help.

[Bugsmema]

We have a 2012 Outback and our blank tank cleaner has stopped working also. Just wondering if David was able to get his fixed.
The replies are fantastic. You can learn so much on here!

[JRTJH]

Originally Posted by Bugsmema

We have a 2012 Outback and our blank tank cleaner has stopped working also. Just wondering if David was able to get his fixed.
The replies are fantastic. You can learn so much on here!

(And davidjsimons too): is it possible that you removed the anti backflow valve last year and could have installed it backwards? I always remove mine to make sure it doesn't freeze and crack during the winter. This year, after we got to Galveston, I reinstalled it to flush the black tank. I had no water flow and thought, "OH NO!!!" then I looked at the valve and I'd installed it backwards. It seemed a little "funny fitting" when I installed it, but it connected to the threads without any hassle.... I simply turned it around and all is good. Could that be your issue?

[Bugsmema]

I know hubby didn't pull anything off that has to do with the black tank for the winter. We've used it on a trip to AZ in Feb. Was working great till our tank got totally full. Not sure if that might have done it. It hadn't been that full before. Also have been using reg TP, not RV kind. That might be the problem. Someone mentioned running hot water down a drain. How will we know which one? Under the kitchen sink, under the bathroom since? A lot of tubing under both! Lol

Thanks,
Bugsmema

[hankaye]

Bugsmema, Howdy;

They were referring to hooking up the Outdoor shower
from T RV to the flush and flushing (attempting to), with
Hot water that way. Personally, I'd get a back-flow preventer
to install between the hose and the flush hook-up. That way
anything that, by chance, bubbles up won't back flow into the
rest of the RV's water system.

hankaye