OOPS-didn't winterize black tank flush

[big craig]

I missed winterizing my black tank flush with antifreeze last fall on our new 2020 Rockwood 2608BS, what can I expect/watch for this spring when I dewinterize?

[kenandterry]

So......you never circulated the pink stuff through the toilet for awhile, so it would empty the pink stuff into the black tank?

I’m guessing you might have water that froze in or near the waste gate of the black tank, because that’s usually close to the low point of the entire tank.
Depending on how much water was there, and if there was space to expand, will determine if there’s any damage there. You won’t know for sure until temperatures are continually warm enough to thaw everything out.

Good luck.

[My17Ram]

I think he means the black tank flushing line from the hose connection on the side of the trailer.

[Semperfi24]

I guess it depends on what you mean by winterize. I blow air into it just to be safe, but I have never added antifreeze. Honestly, not even sure how to add antifreeze to the flush system, as it would require the antifreeze to go uphill several feet. So I wouldnt be all that concerned about it, but with that said, if you did something different, for your own peace of mind, I would suggest paying close attention to it the first time you use it this spring. Preferably with help from someone else (so they can turn it on and , if need be, quickly shut it off for you). But, I would think you will be ok

[kenandterry]

Originally Posted by My17Ram

I think he means the black tank flushing line from the hose connection on the side of the trailer.

Oooops.
I just skipped over the word “flush” and focused on black tank.

[B and B]

I never did on any trailer till this year when I blew compressed air into it. The hose has a vacuum breaker at the high point and gravity usually takes hold and drains the hose.

[BehindBars]

I guess if the pipe split somewhere in the flush line, you wouldn’t know it until you do a tank flush in the future. You’ll just have to test it. Depending on the level of the piping, it could have self drained anyway.

I don’t know how I could put antifreeze in the flush line, but I do just blow it out with air when winterizing.

[big craig]

My previous trailer never had a black tank flush and of course the manual never covered it in winterizing. I will blow compressed air next fall and hopefully its ok this spring.

[Jim34RL]

All three of my 5er's have had the black tank flushing spray. I have never done anything to the flushing system for winterizing the spray line. My theory is that the water from the flush line will drain into the black tank when you are done flushing. Since this is open to atmosphere and above the blank tank this should self drain. The check valve is open to the atmosphere all of the time unless you are getting a back flow.

[Iwritecode]

Originally Posted by Jim34RL

I have never done anything to the flushing system for winterizing the spray line.

Same. Have had fiver for about 5 years now. Never had an issue.

[raysen]

Originally Posted by My17Ram

I think he means the black tank flushing line from the hose connection on the side of the trailer.

I second that motion.
I think the flush line will be fine since it's an open end

[Splashes3]

In 12 years and 2 5vers, I've never added antifreeze to the black tank flush system. Never had a problem come spring.

[lacamastraveler]

Originally Posted by big craig

I missed winterizing my black tank flush with antifreeze last fall on our new 2020 Rockwood 2608BS, what can I expect/watch for this spring when I dewinterize?

Glad to see this post. I forgot to force air through the black tank flush when I winterized my RV (Reminder why I should read my previously written instructions and not rely on my aging memory).

After the first big freeze I remembered it and forced air through.

Big Craig ~ I guess you are our test subject😁. Let us know what you find.

[old40ford]

Originally Posted by B and B

I never did on any trailer till this year when I blew compressed air into it. The hose has a vacuum breaker at the high point and gravity usually takes hold and drains the hose.

X2, I have done both and not noticed any difference. I think you won't have any problems.

[jimmoore13]

OK

Minnesota. I imagine you've seen plenty of sub-zero temps.
And I gather you allowed the rig to drop to ambient temps.

The good news is that PEX can withstand a tiny amount of "stretching." The bad news is that the plastic fittings cannot. The chances are VERY high that, IF WATER SAT IN THE LINE AT ANY POINT, the water would burst any fittings.

The good news is that GRAVITY may be your friend. If the black tank flush (BTF) inlet (hose connection) is ABOVE the black tank (even just a couple inches), and if the hose connecting the exterior fitting to the sprayer on the black tank is relatively straight and has no water-collecting bellies in it, it's possible that the water in the BTF system may have just drained into the black tank. Even if there is a check-valve in the line, that one-way valve may have allowed the water to drain past it - especially if you flushed the tank just before parking the rig for the winter. Given a few days of reasonably warm weather since the last use of the rig, between evaporation and drainage, you could be lucky.

What I would do. Contact the manufacturer and get a description of the system design, what may have happened and what it may take to get access to the BTF plumbing to inspect it and repair it as needed. You may hear that the hose connection on the BTF is higher than the top of the black tank, and that you got lucky. And you may be able to conduct an inspection by dropping the belly cover and using a long extension mirror to see above the black tank. https://smile.amazon.com/Telescoping...3263741&sr=8-5
A factory support tech will probably have a reasonable procedure to conduct the inspection, and with the help of a partner manning the hose, you could test the system under hose pressure and watch for leaks...and scream to shut off the water if there are leaks.

If you're not lucky, then make a decision. Am I up for the work and expense it will take to make the repair? I suspect you'd need to drop the black tank, which is not a small job.

But for sure, if you suspect freeze damage, do NOT use the BTF under pressure without verifying it's integrity. If there is freeze damage, water, at garden hose pressure, could spray all over the place from the failed BTF plumbing. This could soak down insulation, sub floor, and even electrical components.

If it's damaged and you choose not to fix it, you can readily resort to the tried and true techniques of injecting water using a waste valve attachment to back-flush the tank, and get a hose wand to shove down the toilet. If the BTF is freeze damaged, you can simply ignore it unless the fitting that plugs the top of the black tank is so badly damaged that sewage could come out the top...that's pretty unlikely.

Dump Valve fitting: https://smile.amazon.com/Camco-Rhino...3263317&sr=8-1

Black tank cleaning wand for toilet: https://smile.amazon.com/Camco-40094...263386&sr=8-11

So, here's to getting lucky. ...and to blowing it dry with an air compressor next year.

[dnicoll]

I have never winterized the black flush lines either. On my existing Columbus, The connection on the exterior of the trailer rises vertically several feet (inside an interior wall) To a back flow valve, then down to the spray head in the black tank. The lines are self draining on both sides of the valve. When I disconnect the hose from the black flush connection, some water Always drains back into the wet bay (and all over my hands!). Water on the other side of the valve drains into the black tank. I assume most of these systems are similarity plumbed?

[Semperfi24]

Reading through the replies, it seems common to blow out the line, but almost equally common to do nothing, and no one seems to have any issues. So you are probably going to be just fine

[Freetyme]

Never gave it a thought, haven't had a problem yet.

[dbledan]

I did nothing for two years with below zero temps and no issues. Every RV is different so who knows. Now I blown it out just in case.

You could hook it up and see what happens. Just watch it closely and don't walk away.

There should only be 4 fittings and they are open to drain themselves....one to the port on the outside, one either side of the backflow valve, and one to the tank. Worst case you may have to swap the backflow but not likely.

Good luck!

[IchLiebeBier]

Originally Posted by BehindBars

I don’t know how I could put antifreeze in the flush line, but I do just blow it out with air when winterizing.

For those who don't know, and don't use compressed air:

I use the Valterra Hand Pump for this. I pump until I hear water flow out of the black tank flush. Just takes a second to do it.

But I do believe nothing would happen to it if you don't mess with it. I just like to be safe.