Winterize Black Tank Flush(HELP)

[Rockwood Rickk]

Hello all still loving my 2008 255DS I have it all winterized antifreeze in all the spots and areas. But this is my first RV that has a black Tank Flush. Which I actually totally forgot about. I have searched the Forest River Forum and found so many different answers. So you that own a 255DS or other Lexington owners or other Forest River products, what have you done. As some people say they have never touched it. some say if you add antifreeze into the in port it will just drain into the black tank. Others just blow it out. I live in Northern Bc Canada where it is already cold freezing. So am I hooped or is everything going to be ok??

Rick M
2008 Lexington 255DS
2006 Rockwood 8272S
4 Bigfoot trailers

[NavyLCDR]

I just blow it out with air.

[BehindBars]

Ditto. I just blow out the black tank flush line with compressed air.

Whether it is subject to freezing now depends on the routing of the flush line piping. It could be a simple line that self drains anyway, or it could have elevation changes and dips that could trap water.

[bubbles]

The black tank output side (check valve side) drains into the black tank. The vacuum breaker input side (valve cavity) allows the input side to drain back out the input port as the vacuum breaker closes off that port.

[richp]

I completely forgot to do anything with mine for years, and even though we have bitter cold here in the upper Midwest, I've never had any indication mine had water left in it to freeze.

[NavyLCDR]

Whether or not there is water left in it after normal use, it takes me less than 1 minute to move my air adapter from city water inlet to black flush connection and give it a squirt of air. Just not worth taking the chance in order to save 1 minute of minimal effort.

[SailorSam20500]

I run a few puffs of air from my compressor. First year, I didn't even think about it and it was fine.

[BigMoose]

Air! No reason not to.

[gw1800]

I have one of the hand pumps for winterizing. Connect it to the black tank flush and give it a few pumps. I never trust the way they run any water lies. It may have a low spot. Air would work, but you already have the antifreeze handy.
https://www.walmart.com/ip/Camco-RV-...5086c435700381

[reevesfamily]

Originally Posted by Rockwood Rickk

Hello all still loving my 2008 255DS I have it all winterized antifreeze in all the spots and areas. But this is my first RV that has a black Tank Flush. Which I actually totally forgot about. I have searched the Forest River Forum and found so many different answers. So you that own a 255DS or other Lexington owners or other Forest River products, what have you done. As some people say they have never touched it. some say if you add antifreeze into the in port it will just drain into the black tank. Others just blow it out. I live in Northern Bc Canada where it is already cold freezing. So am I hooped or is everything going to be ok??

Rick M
2008 Lexington 255DS
2006 Rockwood 8272S
4 Bigfoot trailers

Just blow it out. If it has water in the line it will freeze and probably break.

[Jimh64]

I also use air just to be safe. One year i forgot but never had any issues and mine sits out all winter in NE Ohio so we get our share if snow and cold!

[Kcoulter]

It *should* naturally drain both ways from the vacuum breaker valve, but I still connect the outdoor shower to the black tank flush during winterizing to give it a quick blast of pink.

[SailorSam20500]

Originally Posted by gw1800

I never trust the way they run any water lies. It may have a low spot.

Having water in a low spot in the pex water line is not really a worry. PEX will stretch and shrink back if a bit of water freezes in the pipe. Note that a pro installation tool for PEX actually stretches the pipe for fast installation.


However, connections and fixtures don't stretch and will break if full of water that freezes. That's what you need to worry about.