Slow Fresh Water Drain; Dewinterizing

[Gliddenwoods]

When we depart from the cold north to begin a trip our Oliver is winterized. Upon a warm State the dewinterizing is to be completed.

Two problems:

1.The fresh drain is so small it takes well over an hour to drain. Has anyone modified the drain outlet to speed up the process? How? If not modify the drain outlet are there other suggestions?

2. Draining the tank in a campground is prohibied. Are other owners driving down the road with the open? Or what?

Thanks

[ScubaRx]

Open the drain while driving to your destination. But why does your fresh water tank have any water in it if it’s supposed to be winterized?

[bugeyedriver]

Steve has a reasonable question about why there is any liquid in the fresh tank at all. Best to have no fluids there at all . . . nothing to freeze.

About the slow drainage, well yeah, you do have a tiny drain pipe exiting the trailer from the fresh water tank.  The tank is many feet long, but only several inches tall.  Not a lot of pressure in the line is available from this configuration, resulting in a puny discharge rate when the trailer is perfectly level.  To fix this, raise the nose of the trailer as high as possible, thus giving more depth to the column of water and resulting in a higher pressure at the discharge port and a higher flow rate.  It will still take a bit of time, but not as bad as a perfectly level unit.

As Steve states, opening the drain while driving is a good tactic, but be prepared for all of the folks passing you, honking and pointing to the back of your trailer as the tank empties.  Ha!

Good luck.  

[Rolind]

I wondered  why there was water in the fresh tank if it was winterized also. I think the OP may be flushing the small amount of rv antifreeze out of the lines and freshwater tank when dewinterizing. I usually do with the fresh water drain open, and even if you fill the tank up a little bit, it takes a while to drain. That would also explain why the OP states it isn’t allowed at the campground. I usually don’t worry about the small amount of rv antifreeze draining onto the campsite. It’s mostly alcohol and just like breaking a good bottle of bourbon at the campsite wo the profanity.

[Gliddenwoods]

The proper way to dewinterize (per Oliver Travel Trailer written and video instructions) is to fill the fresh water tank 50 to 100% to dilute the antifreeze and flush the tank. After which one allows this water to drain out under the camper. So & thus, yes indeed, there is water in the fresh water tank to be drained.

So...back to my original questions; any helpful suggestions?

[DavePhelps]

The FWT drain is at best slow draining given the design constraints of the system.

One issue that can make it much worse is when bits of plastic end up inside the tank from drilling the various holes and not meticulously cleaning it out before installing. I have had these bits bunch up at the tank outlet and at the drain valve. When I added my new water supply draw tube, I cleaned and vacuumed out the tank best I could, and cleaned out the drain valve while I was in there as well. Now, not really wanting to go through that all over again, if it seems plugged up, I'll take my air compressor and blow up the outflow tube (30psi is good) into the tank. This usually clears the occlusions long enough to let the tank drain more normally, which is still slower than I'd like.
Hope that works for you.

Dave

[jd1923]

3 hours ago, Gliddenwoods said:

The proper way to dewinterize (per Oliver Travel Trailer written and video instructions) is to...

How did I miss this one? Don't watch the one either about lubin' the stabilizer jacks! 🤣

[jd1923]

11 hours ago, bugeyedriver said:

raise the nose of the trailer as high as possible

2 hours ago, DavePhelps said:

I'll take my air compressor and blow up the outflow tube (30psi is good) into the tank.

Certainly do these things.

You may also find lifting the front helps at the dump station!

When you blow out the drain (30-50 PSI is good), ALSO blow out the overflow which is under the fridge (only do this when the drain is open). A restricted overflow will impede draining, even if the drain is wide open! Learned this in high school chemistry class. 🤣

And you could use that compressed air to blow out the lines and forget about using antifreeze at all. If OTT in a video actually said to leave the fresh tank half full over winter!?! Please ignore that odd comment!

Your manual drain valve  has a 3/8” opening in a 1/2” PEX plumbing system. I replaced this valve with an electric motorized valve with a 12mm opening (near 1/2”). My tank now drains twice as fast!

I often open the drain while on the road driving home, but don’t do this in prissy locations and those with an abundance of police officers! 🤣

[ScubaRx]

On 3/23/2025 at 4:41 PM, Gliddenwoods said:

The proper way to dewinterize (per Oliver Travel Trailer written and video instructions) is to fill the fresh water tank 50 to 100% to dilute the antifreeze and flush the tank. After which one allows this water to drain out under the camper. So & thus, yes indeed, there is water in the fresh water tank to be drained.

So...back to my original questions; any helpful suggestions?

Why not just use the city water connection to flush all the lines? Then all the flush water will go into the gray tank. Also you don’t have to run your pump. Some folks (myself included) will sometimes overthink a simple issue. Oliver dropped the ball on this one. 
 

[johnwen]

On 3/23/2025 at 9:46 PM, jd1923 said:

I replaced this valve with an electric motorized valve with a 12mm opening (near 1/2”)

JD

I should look at this mod the next time we cross paths!

John

[jd1923]

7 hours ago, johnwen said:

JD  I should look at this mod the next time we cross paths! John

Thanks and can do! 😂 
I have an older, longer detailed post...
but the first post in this thread shows the highlights!

 

[Geronimo John]

On 3/26/2025 at 8:08 PM, ScubaRx said:

Why not just use the city water connection to flush all the lines? Then all the flush water will go into the gray tank. Also you don’t have to run your pump. Some folks (myself included) will sometimes overthink a simple issue. Oliver dropped the ball on this one. 

Maybe OTT did, maybe not.  After all, more than a few folks don't have city water or well water where they store their Ollie.   For them, maybe not.

[Roger]

On 3/27/2025 at 2:08 AM, ScubaRx said:

Why not just use the city water connection to flush all the lines? Then all the flush water will go into the gray tank. Also you don’t have to run your pump. Some folks (myself included) will sometimes overthink a simple issue. Oliver dropped the ball on this one. 
 

Just flushing the city lines doesn't get rid of the anti-freeze pumped into the fresh water tank when the freshwater line was winterized. This is what I am interested in flushing, more so than the city lines.

[ScubaRx]

5 minutes ago, Roger said:

Just flushing the city lines doesn't get rid of the anti-freeze pumped into the fresh water tank when the freshwater line was winterized. This is what I am interested in flushing, more so than the city lines.

Then fill your freshwater tank with clean water and either pump it into the gray tank and then dump or just drain it out onto the ground. That will wash out what small amount of AF that ended up in the fresh water tank.

If you want to kill two birds with one stone, add some bleach to the first flush, let it sit for a few hours and then empty the fresh tank. That will sanitize it as well. I’d then flush it again. 

[jd1923]

2 hours ago, Roger said:

Just flushing the city lines doesn't get rid of the anti-freeze pumped into the fresh water tank when the freshwater line was winterized. This is what I am interested in flushing, more so than the city lines.

I don’t use antifreeze, only compressed air (OTT does not recommend this). With antifreeze, yes use it in your plumbing since that will empty sooner or later into your gray tank.

But do not pump antifreeze into your Fresh Tank! The tank is very slow to empty and difficult to rinse clean. Just blow compressed air to empty the fill line and drain the tank. Two seconds of air while you're waiting 30 min on the tank. No worries next season, just fill 'er up and go! 😎

Edited January 7 by jd1923
Added pic

[Roger]

10 hours ago, jd1923 said:

I don’t use antifreeze, only compressed air (OTT does not recommend this). With antifreeze, yes use it in your plumbing since that will empty sooner or later into your gray tank.

But do not pump antifreeze into your Fresh Tank! The tank is very slow to empty and difficult to rinse clean. Just blow compressed air to empty the fill line and drain the tank. Two seconds of air while you're waiting 30 min on the tank. No worries next season, just fill 'er up and go! 😎

Do you blow all yhe lines or just the freshwater tank?

[jd1923]

15 minutes ago, Roger said:

Do you blow all yhe lines or just the freshwater tank?

I blow ALL the lines, but many here are concerned with this practice since it is not OTT recommend (they used to and then legal got in the way of practicality)! To me it takes me 10 min (half the time) when we get home from a trip and not draining or fussing to get ready again. I use compressed air in my garage every day, so it's right there and ready.

To clear the Fresh Tank inlet is a straight run from hull to tank, so there should not be (false) concerns of damage to the water pump or anything else.

See this procedure which I wrote up a couple years ago. BTW, step #13 was suggested and I added it but I don't believe it's necessary and have never done this step. I've never used RV antifreeze in three RVs we're owned.

 

[Mike and Carol]

2 hours ago, jd1923 said:

I blow ALL the lines, but many here are concerned with this practice since it is not OTT recommend (they used to and then legal got in the way of practicality)! To me it takes me 10 min (half the time) when we get home from a trip and not draining or fussing to get ready again. I use compressed air in my garage every day, so it's right there and ready.

To clear the Fresh Tank inlet is a straight run from hull to tank, so there should not be (false) concerns of damage to the water pump or anything else.

See this procedure which I wrote up a couple years ago. BTW, step #13 was suggested and I added it but I don't believe it's necessary and have never done this step. I've never used RV antifreeze in three RVs we're owned.

 

I use an air compressor similar to the method JD  posted.  I’ve never used antifreeze.  We do get below freezing a few times each winter and have had several days in single digits since we’ve been Oliver owners.  When a serious freeze is forecasted I bring the trailer home and use a couple of electric heaters inside with the inner hulls open.  No problems to date.  I’d be a little more vigilant if we were in colder areas.  We’ve been in the upper 70s since Christmas, but will probably get one or two freezes before spring.

[jd1923]

22 minutes ago, Mike and Carol said:

When a serious freeze is forecasted I bring the trailer home and use a couple of electric heaters inside with the inner hulls open.

We set our furnace at the 40F min on our thermostat. Yes, this uses some LP but the furnace is in proximity to most of the plumbing. I would worry more with any kind of space heater, and we’re all about NOT moving beds!

But I don’t do it because I think my compressed air winterizing isn’t 100%. I do it since barely a week goes by where I’m not in the Oliver for something and don’t want the interior sub-zero! At 5400 ft elevation, we get a lot more overnights in the teens than in Texas or other SW locales. 

Edited Wednesday at 08:55 PM by jd1923