Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses - 3" Diameter

Part Number: F02-4350

138 Reviews | 25 Questions

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flush king rv waste valve valves reverse for holding tanks and sewer hoses - 3 inch diameter

flush king rv waste valve valves manual reverse for holding tanks and sewer hoses - 3 inch diameter

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Breaking Down the Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses

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Flush valve allows you to rinse out your wastewater tanks and flush out your sewer hose, breaking up clogs and cleaning tank sensors. Built-in backflow preventer keeps water source contaminant-free. Clear barrels shows when tanks are clean. Great Prices for the best rv waste valve from Flush King. Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses - 3" Diameter part number F02-4350 can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.

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Reviews (138)
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Flush King RV Waste Valve - F02-4350

Features:

Flush valve allows you to force fresh water through your holding tanks and sewer hose from outside of your RV
- Breaks up clogs in plumbing lines
- Cleans tank probes to help prevent false readings on monitors
- Eliminates the need to use tank wands and rinsers
Built-in backflow preventer keeps water source free from contaminants
Clear barrel lets you see when your tanks are clean
Blue knob allows you to direct the flow of water
- "Tank" backflushes your black-water and gray-water tanks
- "Hose" rinses your sewer hose
- "Off" stops the flow of water
Valve handle swivels 360 degrees for easy operation
Simple installation and removal - no tools required
- Easily refill and flush tanks at any height or bend of plumbing
- Bayonet fitting secures to standard 3" lug fitting on RV's waste valve
- 3" Lug fitting allows you to connect to sewer hose
- Rinse hose (sold separately) connects to the female coupling on barrel
- Inner seal helps prevent leakage at the connection point

F02-4350 Valterra Flush King Reverse Flush Valve for Motor Home Holding Tanks and Drain Hose

Customer Satisfaction Score:

98% were satisfied with this product

2% of customers were not satisfied

Arrived Damaged

2% of customers were not satisfied

Arrived Damaged

4.8

138 reviews

5 Stars		(116)
4 Stars		(17)
3 Stars		(2)
2 Stars		(1)
1 Star		(2)

by: Mike 09/08/2026

The flush device worked very well. Got my tanks flushed out good. Thanks for a great product and great service,Mike

by: CTamez 08/19/2021

Who decides on size of box for shipping and do you train them on securing product for shipment? I ordered two wiper blades, two heater door clips, sewer flush king and sewer cap. They were shipped in a huge box (21"x26"). So big that the flush king came out of its packaging from being tossed around inside the box. I'm sure everything was bounced around the entire trip to my door cause there was only one small strip of filler for cushion and the box was crushed onretailer. It could have been shipped in a box half that size. I'm actually not expecting my flush king to stay together long. Disappointed in the shipping package. I guess you take your chances. I never expected this from etrailer.

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by: Mike 08/23/2026

Haven't used it yet! know it works from watching a friend use it while traveling together.

by: Jon 01/19/2026

Works great!! I have used this to back flush both grey and black tanks and on the black tank side (after initial flush) it has removed more solids.

by: Jim / 08/12/2019

VERY impressed with product, my first time "back-flushing" the black-tank & was impressed with the amount of dried toilet paper flushed! A+++

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by: Jack 05/06/2026

Bought for use with our camper but haven't had the chance to use it yet. Looks/feels solid & I expect it will perform its function as designed.

by: Kim 02/13/2026

Helps me dump tanks ore efficiently

by: General Delivery 05/26/2026

Great Service,

by: David 03/23/2026

Works great

by: Joe 04/21/2025 One Year Later

Even though I have a black tank flush port, this adapter allow better water flow into the tank for flushing, and of course use on the gray tanks that don’t have flush ports.

by: Roamer 2010 09/10/2018 One Year Later

I purchased the Flush King device to solve a problem I had with Black Water Valve not closing all the way. I suspected some type of debris was causing the gate valve to not seat correctly. The Flush King device allowed me to back flush the line near the source of the problem and the dump valve is now working great. Every RV owner should have access to the a Flush King device to keep your dump tanks free and unobstructed.

I also purchased a wand so I can flush the Black Water Tank from above. This is a great tool for cleaning sensors and pipe between toilet and tank.

by: Joseph 06/27/2026

Does not work on my class A. The drop needs to be an inch or two greater. Can not attach. So be carefull it’s not universal fit. Mine is Thor Windsport 29M

James D.

6/30/2026

Thank you for sharing your experience, sorry to hear the Flush King wasn't compatible with your Thor Windsport 29M. While it's designed to fit many RV setups, there are some motorhomes where the sewer outlet configuration doesn't leave enough clearance for it to attach properly.

by: Joe 08/07/2018 One Year Later

Works great for our fifth wheel that didn’t come with a factory installed black tank flush system. Use this every time we are done camping and the smells are gone and tank sensors read as they should. Well worth the money!

by: John 11/13/2025

Delivered with no damage and functions as advertised.

by: Scott 07/30/2019

Wow this thing works! I not only cleared a black tank stoppage that prohibited the black tank frm draining at all, I cleaned both the grey and black tanks...

My neighbor is using it this week to clean his tanks as well - this is a device that is now built in to some of the newer RVs, because its needed and works so efficiently,,,

Scott W. One Year Later

7/31/2020

Sensor s can get fouled and distort actual tank levels this litle guy is perfect for cleaning out the tank and removing old slime, etc etc etc

by: Steven 09/11/2018 One Year Later

The best trailer accessory ever. It is working great after a year. No leaks. Versatile. Rotates to accommodate the various geometries of the curbs at dump stations. Two back flushes usually gets everything cleaned out of the black tank. The clear pipe shows it is working perfect! If this ever breaks I will buy the exact one again.

by: James 08/10/2021

I had one of these and just loved the way it worked and helped me be sure my holding tanks were clean and empty. Unfortunately, on our recent trip something apparently came up off the road and made it disappear as well as breaking a fitting on the line coming from the trailer. I've gotten so used to using this that I really hated to dump without it.

We buy quite a bit of things from Etrailer for our business equipment and my RV. Always get good service.

by: James 04/01/2025

Purchased this after seeing the water flow in the Camco version was significantly less. This has great flow to reverse flushing your tanks.

by: Jeff 04/21/2025 One Year Later

This valve is a must have to help keep your tanks clean! We are FT and it is a normal part of our set up. Works a well after a year of use.

Heather A.

4/23/2025

Hey Jeff! How is full time RVing going for you guys!? What a dream.

by: Louis 11/23/2018 One Year Later

Product worked great. Black water tank was clogged bad. Paper had dried hard over drain. 1 place told me I needed another tank. Another place put chemicals in but that didn’t work. I tried snakes and nothing worked. The flush king blew the clog apart and everything worked flawlessly. Great product

by: Gary M 09/03/2017

I had a clog in the outlet of the black water tank. I ordered this from George on a Sunday. It shipped on Sunday much to my surprise. Came to me in excellent condition. I hooked it up and it worked as advertised. Cleared the clog and cleaned the tank. I flushed it about 3 times and was getting clear water. It also cleaned the sensors so the tank is showing empty. Its been 2 years since they have worked. Excellent product and excellent service

by: Bill R. 07/09/2020 One Year Later

Great product. I backwash every tank Black and Gray. My black tanks have interior sprayers. Between the flush king and sprayers my tanks are ready for a long winters nap. No smells...

by: David 01/27/2022

The valve made flushing both tanks easier than putting a hose inside the camper trailer.

David One Year Later

1/30/2023

The product works great especially when I am by myself when flushing the tanks.

by: Mike Y 01/17/2020 One Year Later

Used one time. Worked PERFECT!!!! Wife was ecstatic!!!! WE had a black tank that wasn't draining. Installed the device. pressurized the system and it blew the clog out. Back washed a couple times, haven't had a problem since. Anyone who owns an RV should have one. Wish I had found it sooner. Thank you
.

by: Steve 04/24/2020

I just received my order this afternoon. Very surprised at the speed with which it was delivered. I am in the process of rebuilding a older5th wheel and the items that were ordered are just perfect for the job.
Thank-you etrailer I will be back

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See what our Experts say about this Flush King RV Waste Valve

Do you have a question about this RV Waste Valve?

Replacement Seal for Flush King Reverse Flush Valve
Hello Dwayne; the # T201 is the correct seal for your Flush King # F02-4350.
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How to Know When Blank Tank is Full When Using Flush King Reverse Flush Valve
Thank you for the photo, and there should be sensors with a monitor for your tank that tells you how full it is in order to use the Flush Valve for RV Holding Tanks and Sewer Hoses # F02-4350. If you don't have that, you can still use the Flush Valve # F02-4350 but you'll want to be sure to limit the water flow going in so you don't have a real mess. But really, this is best used with black water tanks that have monitors which tell you how full it is. This will work for you unless your...
view full answer...
Solution for Waste Water Staying in Sewer Hoses on RV
What I strongly recommend instead that will fix your problem is the Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses - 3" Diameter # F02-4350 because it is designed for the exact problem you are having. It will flush the hoses so the waste water does not stay the "T" on your photo. It would require you to hook up a hose, Flushing Hose for RV Sewer System # W01-4180 (15 feet) or # W01-4300 (25 feet) but would be the remedy to your issue. I have added a link to a video...
view full answer...
Replacement City Water Connection Inlet And Black Tank Flush Inlet For A 2021 Forest River Salem FSX
I do have replacement parts for your 2021 Forest River Salem FSX Travel Trailer. You will have lots of options. There are different cutout diameters and flange diameters for your city water connection inlet. If your cutout diameter is 1-1/2", you can use the RV City Water Inlet with Brass Check Valve - 1/2" MPT - Metal Flange - Surface Mount - White, part # 37262165. You will have to measure the cutout diameter and the flange diameter to determine which part will work for you. It can connect...
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Can Flush King Reverse Flush Valve # F02-4350 Be Connected at all Times
The Flush King Reverse Flush Valve # F02-4350 that you referenced gets connected to your bayonet sewer fitting and used and then removed when not in use. I would not recommend leaving it installed all the time.
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What is Difference Between Flush King Reverse Flush Valve # F02-4350 and Hydroflush Reverse Flush
The reason the Flush King Reverse Flush Valve # F02-4350 costs more is because it comes with a valve on the end of the swivel fitting whereas the Valterra Hydroflush Reverse Flush Adapter # F02-4110 is basically just the elbow fitting with bayonet fittings on either end. Both would use the same type of fitting as the hose extension part # W01-0009.
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Replacement Seal For Flush King Reverse RV Flush Valve
I called my contact at Flush King and they told me the replacement seals you need are part # T1003-9VP. These are the seals that go between the clear plastic waste tube and the body of the waste valve. If this is not the gasket you were asking about let me know and I will see if I can find the gasket you need.
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Will the Flush King Reverse Flush Valve Work With Grey Tanks
Yes, the Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses # F02-4350 will also flush your grey tank.
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Function of Blue Knob on Flush King Reverse Flush Valve
The blue knob on the Flush King Reverse Flush Valve # F02-4350 will allow you to direct the flow of water with the unit. I've added a link to a video review of this valve for you to take a look at as well.
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Can Flush King be Permanently Mounted
The Flush King Reverse Flush Valve # F02-4350 should work great for you but I do not recommend permanently mounting it. I have heard of some people doing this but to get the best, longest-lasting use out of this I highly recommend only using it when needed as opposed to keeping it on when you are traveling. I have added a link to a video review of the Flush King for you to take a look at.
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Can Lubricant be Used on the Valve Handle for the Flush King Reverse Flush Valve # F02-4350
You can definitely try using some lubricant like WD-40 or PB Blaster to see if it will loosen up the handle. Since the mechanics for the handle on the Flush King Reverse Flush Valve # F02-4350 are really simple it shouldn't take much more than that. You will just want to work the handle a little after spraying it to make sure that the lubricant spray spreads around a little.
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Recommended Flush Valve and Tank Rinser
Based on what you described I do not think the Flush King Reverse Flush Valve item # F02-4350 is going to be the right part for you. Sounds like you've got too much distance for the water to travel from the opening. Instead, I recommend using the Tornado 360-Degree RV Holding Tank Rinser w/ 6' Long Hose item # CAM40126. The Tornado item # CAM40126 installs in the side of your tank and has a 360-Degree rotating head with 10 high-pressure nozzles which reaches every area of your holding...
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Weight of Flush King Reverse Flush Valve # F02-4350
The Flush King Reverse Flush Valve # F02-4350 referenced in your question is very lightweight at just under 2 pounds. This valve will allow you to rinse out your wastewater tanks and flush out your sewer hose. It features a built-in backflow preventer to keep the water source contaminant-free. I have attached a short video demonstration on this product that you can also check out.
view full answer...
Will the Flush King Reverse Flush Valve # F02-4350 Help Prevent Misreadings from Tank Monitors
Using a connection like the Flush King Reverse Flush Valve # F02-4350 for your sewer system is a great idea because it definitely can help prevent false readings on your monitors. By rinsing out your tank you will be cleaning the tank probes, allowing you to get more of an accurate reading, as well as breaking up clogs in your plumbing lines. The clear barrell will allow you to see when your tank is clean so that there is no guessing involved. I have attached a review video for you...
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Recommended Rinse Hose to Use with Flush King Reverse Flush Valve
For a standard flushing hose that will work great with the Flush King Reverse Flush Valve # F02-4350 referenced in your question, I recommend using either the 25 foot Valterra Hose # W01-4300 or the 15 foot # W01-4180. These will work perfectly with this valve and allow you to rinse out your wastewater tanks and flush out the sewer hose. I have attached a short video demonstration on this product that you can also check out.
view full answer...
Replacement Flush King Valve and Viper Extension Sewer Hose
I'd be happy to help you out, Ruth! The sewer hose you're looking for is the Viper RV Sewer Hose Extension w/ 3" Swivel Fittings # D04-0410, and then to replace your Flush King I believe you're talking about the Flush King Reverse Flush Valve # F02-4350. Both parts are linked to this answer page and you can get to their product pages by clicking on their numbers. I wasn't able to find anything with the specific Flush Valve part number you referenced, so if yours looks different than...
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Recommended Sewer Hose to Use with the Flush King Reverse Flush Valve # F02-4350
I recommend using the Viper RV Sewer Hose Kit # D04-0475 to use with the Flush King Reverse Flush Valve # F02-4350. This sewer hose kit come with two 10' hoses so that you can just use one if you are able to get closer to the dump site. I also recommend using the Sidewinder RV Sewer Hose Support System # CAM43041 from Camco which will hold your hose and has a slight slope to it so that you don't have to constantly be lifting the hose to make sure everything gets to the dump site. If you...
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Does Valve Handle Swivel on Flush King Reverse Flush Valve?
Yes, the valve handle can go sideways on the Flush King Reverse Flush Valve # F02-4350; in fact it swivels 360 degrees. I've added a link to a video review of this product for you to take a look at as well.
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Is the Flush King Reverse Flush Valve Good to Use for a Black Water Line with Two 90 Degree Elbows
Since you have two 90 degree elbows in your black water line I recommend using the Camco Tornado 360-Degree RV Holding Tank Rinser # CAM40126 because it will be much more effective at cleaning your holding tank than the Flush King Reverse Flush Valve # F02-4350. The Tornado installs in the side of your tank and has a 360-Degree rotating head with 10 high-pressure nozzles which reaches every area of your holding tank. This also comes with a 6' long hose to give you easy access and a built-in...
view full answer...
Can Gate Valve Handle Swivel on Flush King Reverse Flush Valve
The Flush King Reverse Flush Valve # F02-4350 referenced in your question will allow you to rinse out your wastewater tanks and flush out the sewer hose for your RV. It does feature a 3 inch gate valve and it is not in a fixed position. The handle itself can swivel and will operate by pulling up vertically. I have attached a short video demonstration on this product that you can also check out.
view full answer...
Black Water Flush Valve for Black Water Tank Access at Tight 90 Degree Angle
The Flush King Reverse Flush Valve # F02-4350 will work for a tight 90 degree angle but there are other options that would work better such as the Valterra No-Fuss Flush with Check Valve # A70 which would get installed in the side of the tank with the access on the outside of the trailer/RV wall.
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Is Backflow a Problem with the Flush King Reverse Flush Valve # F02-4350
You would need to keep an eye on the Flush King Reverse Flush Valve # F02-4350 when flushing the holding tank but it does have a built-in backflow preventer to keep the water source from getting contaminated. I have linked a video review of this valve for you.
view full answer...
Replacement for Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses
The Flush King Reverse Flush Valve for RV Holding Tanks and Sewer Hoses, # F02-4350 uses bayonet fittings to secure the lug fitting from the hose onto RV's waste valve. These are not replaceable individually. You will need to purchase a new Flush King, # F02-4350.
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Reverse Flush Valve For 3 Diameter Hoses On RV/Camper Black And Grey Water Tanks
Yes, the Flush King Reverse Flush Valve - 3" Diameter Item # F02-4350 is designed so you can leave the valves open when flushing out the tanks. This makes it easier than using a rod because you simply thread the hose on the fitting and it forces water into the tank to flush it and the drain hose.
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