Black Tank Flush problem

[patodonn]

It appeears that there is a restriction in the water flow of the black tank flush system. I had the flush water on with the tank valve closed (as a test of the system) for over 20 min and still didn't fill the tank. That is less than 2 gpm flow, which is very low with normal water pressure. Most logical problem is the vacumn breaker valve under the sink...it is quite noisy, and I can hear/feel water going through both inlet and outlet sides of the valve. That is the only restriction point in the sytem I can find. Anyone know if the valve is a "off the shelf" item at Camper World? If a replacement valve isn't available, can it be removed and bypassed without any problem?

Thanks,

[NJ Hillbilly]

Some have removed the Vac breaker and replaced it with a valve int the storage compartment. I may do this in the Spring also. Just make sure You use a screw on vac breaker for the garden hose. These can be found in the plumbing section, they attach to hose bibs.

I'd try that first before going any deeper in the investigation.

John

[sreigle]

I don't know if it's off the shelf or not but wanted to ask a question about John's comment. I read somewhere, in this forum I think, that the vacuum breaker needs to be above the level of the toilet valve. I'm wondering if that's right or does it need to just be above the black tank itself? Or neither of the above?
Thanks.

[Jeilering]

We have had the same problem with our 3295, seems as the flushing line had a kink in it just after the filler connection...our was easy to see as it is visible under the corner china cabinet...I have also replaced the black water flush check valve located under the vanity, ours started leaking once in a while and finally realy broke loose while traveling, my temperary fix prior to replacing was to take it out of the line entirely by connecting the pipes together using a water heater bipass line which I got at a local rv store.. My dealer was able to get me a new valve.

[Northstar]

Thanks for the neat info. Keep us posted. Happyrving.....

[On The Road Again]

I'm having the same problem with the flush for my "black water" tank, slow, slow, slow, however, I don't know what the "vacuum breaker valve" is or where it may be located on my 2004 3280. I'm scheduled to take the rig to my dealer on the 30th of this month for this problem, but sure would like to resolve it before then since we're leaving in another week for a camping trip.
Any ideas are welcome....
Thanks,
Marshall

[sreigle]

Every one I've seen is in the cabinet under the bathroom sink.

[NJ Hillbilly]

Steve, that is correct. The vac breaker will allow water to flow from the tank toward the valve. This is why it is higher than the highest point of the system, the water level in the bowl. In theory the water level could go that high and equalize itself up the flush line.

My flush stopped working this weekend again. Since my trailer is going back to the factory again I will let them deal with it.

John

[On The Road Again]

Thanks to all of ya'll for the suggestion concerning the "valve" under the bathroom sink being the problem, cause that was exactly where my problem was located. For some unexplained reason that "valve" was stuck and the dealer got it unstuck by "blowing" air at 120psi thru it and now it works great...like it should. Hopefully it won't get "stuck" again, but for some reason it came from the factory apparently "stuck".
Again, thanks to all.
Marshall