Water Siphon through Winterize Port

[Unraveled4218]

Just picked up my 2025 Keystone Cougar 28BHS yesterday. Came from a Jayfeather 24BHS. I spent most of my day today trying to understand the differences in systems and I'm feeling stuck on the fresh water situation. Once I realized there wasn't a traditional gravity fed port, I quickly started trying to figure out how I could get water into the system from a jerry can for the longer trips where there isn't a water hookup (most state parks in Michigan).

I've found a thread discussing an idea of using the siphon and then pushing water through the shower port into the city water port. While the logic seems solid, it doesn't look like anyone actually tested that.

I kept digging and realized the panel behind the water service station is a door so I opened it up and snapped a couple of pictures of the plumbing. To me it appears that if the Winterize port is attached to a hose going into a jerry can, and the winterize valve is set to ON. The pump will pressurize that fluid onto the main water branch. From the main water branch, the Tank Fill valve can be set to Tank Fill. When looking at the plumbing from the back, it appears this would dump water into the fresh tank.

Thoughts?

 

[Randy23LT]

Not sure if yours is the same, but on my Cougar 25RDS the gravity fill port is outside the TT near the electrical plug in. Not in the wet bay.

 

[NH_Bulldog]

Keystone switched it around in 2024. My March 2024 build has a gravity fill at the rear, but later 2024 builds moved it to a power fill in the wet bay, so it is the “new normal”. I prefer the gravity fill since we do quite a bit of camping off-grid. I have a portable sewer tote to drain the tanks when they get full and I can use 6 gallon jerry cans to refill the fresh water as needed.

My brother’s Fuzion has the power fill and there is no way that we identified to use the onboard pump to fill the tank without some creative replumbing. Even then, the onboard pump is not designed or built to run constantly for the extended length of time necessary to fill a tank. We located the tank vent on the exterior wall, popped it out and then used water cans to add to the tank in a pinch.

You simply need to be aware of your limitations and fill the tank on your way in, then use your available supply sparingly. Otherwise, you can pick up a small external pump (like a drill mounted model) to fill the onboard tank as needed.

 

[Don77]

We where camping in a gold claim for about 3 years and had to bring water in 25 gal. tank in the back of my truck each time we came up. I used a 12 volt transfer pump to trasfer the water and that worked very well for the time we where there.

Don

 

[flybouy]

The tank fill via shore connection contains a one way valve to let water in and not out. That line requires pressure to open that valve. The water pump also has a check valve so "ba k filling is not possible. Realistically the best way is to get a stand alone pump (transfer pump) to fill the fresh water tank.

 

[Unraveled4218]

Not sure if yours is the same, but on my Cougar 25RDS the gravity fill port is outside the TT near the electrical plug in. Not in the wet bay.

Unfortunately, just a vent. I pulled on it a bit and the vent cover is caulked all the way around the top and sides.

My brother’s Fuzion has the power fill and there is no way that we identified to use the onboard pump to fill the tank without some creative replumbing. Even then, the onboard pump is not designed or built to run constantly for the extended length of time necessary to fill a tank.

SeaFlo's website says the 33 series pump (currently installed pump) has been tested to 24 hours of continuous runtime. It has thermal protection as well. 800 hours overall life. We do 4-5 trips a year and usually refill once per trip. Seems like 800 hours is going to take awhile to burn though.

I will admit though, one of my thoughts is to just buy a copy of the pump and use that as my transfer pump. That way I always have a "spare".

The tank fill via shore connection contains a one way valve to let water in and not out. That line requires pressure to open that valve. The water pump also has a check valve so "ba k filling is not possible. Realistically the best way is to get a stand alone pump (transfer pump) to fill the fresh water tank.

If you look closely at the plumbing photo, I'm not seeing how the water pump would backfill, it comes on the "out" side of the pump into the pressurized side of the system.

I'm going to test out the theory on our first trip in a few weeks. If it works, I'll report back and buy a spare pump to carry around.

 

[flybouy]

Here's how, the ,pump is connected to the same water line as the water hose is connected to. If the pump didn't have a check valve then while on city water the pressurize water would push past the pump diaphragm and fill the FW tank. There are many posts on the forum dealing with issue.

Because the water sources share a common water line, if the city water did not have a check valve water would push out of the city water connection when the FW pump is in use. BTW, there's a check valve on the output side of tank type water heaters as well. That's there to keep hot water from backing into the cold water line.

If you decide to "experiment" with replubing the convenience center I'll offer some advise. First, take lots of pictures from various angles so you will know how to restore it back to the factory connections. Secondly, label all the fittings and connections to make restoration easier. Third, before starting, buy some pet tubing, fitting and clamps so you can put it back together again. These steps could save you a lot of time and headaches.

 

[NH_Bulldog]

Keep in mind that RV manufacturers are always trying to cater to the largest market of users. Over the years, the camping style of most buyers has changed and moved away from camping with limited services, to a more glamping type experience where the majority of users are staying at "resort" type parks with full services. If people are staying at parks with full hookups, why do they even need a water tank at all? Another casualty of this mindset is the elimination of the gas absorption refrigerators.

If being able to fill your water tank with the onboard pump was simple, easy and inexpensive, Keystone would have built the system as you wanted it to be built. However, there are check valves and plumbing routes that do not allow you to simply use the onboard pump to fill the tank, many have tried, most all have failed. Save yourself the headache, just get an external pump and use it to put water in the tank the way your system was set up to do.

 

[Unraveled4218]

Here's how, the ,pump is connected to the same water line as the water hose is connected to. If the pump didn't have a check valve then while on city water the pressurize water would push past the pump diaphragm and fill the FW tank. There are many posts on the forum dealing with issue.

Because the water sources share a common water line, if the city water did not have a check valve water would push out of the city water connection when the FW pump is in use. BTW, there's a check valve on the output side of tank type water heaters as well. That's there to keep hot water from backing into the cold water line.

If you decide to "experiment" with replubing the convenience center I'll offer some advise. First, take lots of pictures from various angles so you will know how to restore it back to the factory connections. Secondly, label all the fittings and connections to make restoration easier. Third, before starting, buy some pet tubing, fitting and clamps so you can put it back together again. These steps could save you a lot of time and headaches.

Ah, I think we weren't on the same page about where the water might enter the system. In my scenario the water is entering via the "Winterize" port. Nothing would enter via the "City Fill".

 

[flybouy]

The winterize port draws from a short hose and gets pumped into the main water supply, not the FW tank. If you intend re change that plumbing to redirect water to the FW tank then good luck. I personally wouldn't do it because just for fear of giving a a dealer and/or Ketstone an excuse to deny a warranty claim.

In my opinion, a 12v transfer pump is the easiest solution. Transfer pumps are typically higher volume & lower pressure than FW supply pumps. You could tap off the 7 way truck plug or make an adapter to power the pump. It would likely empty a 5 gal water jug in under 2 mins. and not compromise the integrity of the trailers plumbing.

Good luck in your endeavor.

 

[Unraveled4218]

If you look at the "Tank Fill Power Fresh" valve on the backside photo you can see it simply is an ON/OFF to direct water to the FW tank from the main water supply. No need to change anything on the TT.

I couldn't let it go so I went out and bought new antifreeze so I could test it...

IMG_0243.mov

drive.google.com

Hope this helps anyone else who finds themselves needing to get FW in their TT.

 

[NH_Bulldog]

So how are you getting water from the winterize port to fill your tank? Obviously, the winterize siphon works to pull liquid into the pressurized plumbing system so that you get antifreeze to all the fixtures, but the issue you are trying to solve as I understood it is how to get water from the siphon to feed into the fresh water tank and not the pressurized plumbing system?

 

[Unraveled4218]

So how are you getting water from the winterize port to fill your tank? Obviously, the winterize siphon works to pull liquid into the pressurized plumbing system so that you get antifreeze to all the fixtures, but the issue you are trying to solve as I understood it is how to get water from the siphon to feed into the fresh water tank and not the pressurized plumbing system?

That's the beauty of what they did, intentional or not. The FW tank fills off the pressurized plumbing system.

My artistic skills are lacking but I marked the flow from winterize port to pump in yellow then from pump to tank in green.

 

[JRTJH]

Ah, I think we weren't on the same page about where the water might enter the system. In my scenario the water is entering via the "Winterize" port. Nothing would enter via the "City Fill".

As stated, the "winterize port" does not connect to the fresh water tank. It connects to the cold water plumbing "high pressure side" which supplies water to the faucets and toilet as well as the water heater where it's heated for pressurized water to the hot water faucets. There is no connection from the pressurized side of the "suction line used for winterizing" to the fresh water tank. The water pump is "between the two and it has a one way valve preventing the "winterized fluid/your intended water source" from entering the fresh water tank...

 

[Unraveled4218]

The two circled parts are sources of pressurized water. One is the pump, which can push liquid from “Winterize”. The other is the “City Water” hose connection. If you follow that PEX line, it comes to a valve that is marked by X. This is the valve for filling the freshwater tank. The fresh water tank in this TT is plumbed to fill from the main pressure line.

Check out the video. The water is clearly being siphoned from the water jug and when I turn the valve to “Fill” the water gushes from the freshwater tank drain.

Anyway, I think I’ve documented and demonstrated this well enough for anyone who might go searching. It clearly works on this particular setup without modifications.

 

[NH_Bulldog]

Are you referring to that piece of blue PEX hanging down in your video? That is the plumbing lowpoint drain for the pressurized water system, it is NOT your fresh water tank drain. The fresh water tank drain should be at the very rear and it will be a white pipe sticking down.....

Close the low point drain valves, and then do that same test. Show me a video of you pumping water from your jug and that water pouring out of your fresh water tank drain (only) and I may become a believer. Otherwise, it is like John said and I have said, and others have said, there is no direct connection to the tank fill from your water pump unless you replumb the system.

Your fresh water tank vent on the exterior rear wall will be directly above your fresh water tank, and the fresh water tank drain will be directly below your fresh water tank poking out of the underbelly.

 

[Unraveled4218]

The drain in the video is the freshwater tank drain. The only other drains are the hot/cold pressure side drains on the other side of the TT. I scanned the entire underneath of the TT verifying this.

Trailer went back to parking today so no more messing with it for now. Have a trip in 2 weeks so I’ll capture more details including tank level sensors etc when I get it out to sanitize the system.

 

[essarebee]

This might not help anyone, and is somewhat off-topic, but I want to post what I do. I have an outdoor shower hose adjacent to the gravity fill port. I set my valve to "winterize" to draw water (suction) from a container on the outside of the RV (I permanently ran a length of hose from the winterizing valve on the inside to the exterior). I place the shower hose into the gravity feed port and pump away to fill my fresh water tank. It's very easy for me.

 

[NH_Bulldog]

But if you have a gravity fill, what is the point in using a Rube Goldberg setup in place of just pouring water directly into the filler port? And if you permanently installed a hose to the winterizing valve to the exterior, how do you winterize your camper?

I always carry one of these; quick, easy, and nothing to break down.

 

[essarebee]

It's all about camping styles. We frequent primitive campgrounds with no hookups. Once the fresh water tank we arrive with is depleted, it's easy to fill a container at a hydrant and pump it into the RV tank. I often use 6 gallon jugs and I don't like holding them up to pour into the gravity fill. Time consuming, awkward to hold 50 lbs. aiming for a small hole, and likely get somewhat wet.
The added hose is empty unless I'm actively transferring water, so no cold weather issues.