winterizing black tank flush with air

Yes, it will just blow that water into the black tank.

I've done it that way on my previous TT. Never had a problem.

On my current 5er, I simply hook up the outside water faucet (sprayer, shower, blue coiled hose, hot and cold faucet) in my wet bay, to my black tank flusher (in my wet bay) then pump the pink RV antifreeze and watch for "pink stuff" to flow out the black tank outlet. Once it flows "pink" out the black tank drain, I know both the outside faucet and the black tank flusher line is winterized.

And by the way, I do this when camping too, so I don't have any dependency to hook up a garden hose to the black tank flusher.

Unless it's full, I don't think it will do harm.

Pipes and water tubes burst with the expansion of water when it freezes in confined space.

Yosemite Sam1 wrote:
Unless it's full, I don't think it will do harm.

Pipes and water tubes burst with the expansion of water when it freezes in confined space.

This is what you want. No need to empty the black tank. In fact it is not a good idea to completely empty the black tank. You seals will / can dry out and start to leak. plus the dreaded dry tank smell.

Yes, I just blow them out.
Our new TT doesn't seem to have any backflow device though...

I just blow mine out as well.. That just gets any standing water OUT of the line...

ScottG wrote:
Yes, I just blow them out.
Our new TT doesn't seem to have any backflow device though...

Yup, just blowing is fine. Are you sure it's not hidden Scott? I always thought this was required on a new trailer equipped with BTF? Mine is behind the shower faucet assembly, really hard to get at.

Jerry

Terryallan wrote:

Yosemite Sam1 wrote:
Unless it's full, I don't think it will do harm.

Pipes and water tubes burst with the expansion of water when it freezes in confined space.

This is what you want. No need to empty the black tank. In fact it is not a good idea to completely empty the black tank. You seals will / can dry out and start to leak. plus the dreaded dry tank smell.

Water heater doesn't completely empty of water either with drain plug sitting a littler higher than the base of the tank. But it's insulated too so no worry.

ScottG wrote:
Yes, I just blow them out.
Our new TT doesn't seem to have any backflow device though...

It probably does. I had the same issue of disconnecting the hose and water flowing back out. What I figured out is that the back-flow check-valve is on the other side of the trailer where the sprayer is attached to the tank. Behind the wall where I hook up the supply hose the line that goes over to the black tank goes up first. So when I disconnect the supply hose the water on my side of the check valve can still flow back and out the inlet. I simply added another check valve right behind the wall.

OP .... Sorry for the off topic right turn on the thread.

A side note. Also blow out your fresh water fill line with fresh tank valve open.