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90 degree water supply fitting for RV toilet

Andonso
Explorer
Explorer
Hello,

I'm looking for a 90 degree fitting to connect a new Thetford toilet to a water supply pipe installed in the floor. The RV's water pipe supply pipe is made from a stiff grey plastic that's not able to make any bends more than a few degrees.

I believe but not completely certain the fittings is 1/2 inch NPT and would require a one MPT and one FPT (male/female) fitting on either end of the 90 degree elbow. The MPT fitting should be able to swivel.
10 REPLIES 10

Andonso
Explorer
Explorer
I'll keep an eye on it. I think if nobody disturbs it will be ok.

The thing to remember with these is not to overtighten, not much of the female thread lock into the male threads. The only thing that prevents the supply line from leaking is the gasket inside. I normally hand tighten and sometimes a little more with a wrench. You can't crank down on them similar to metal pipe plumbing.

Another thing to note: the type of union used may make a difference with leaks. Metal unions are thinner than plastic unions and fit differently to various type of other fittings such as found on hoses, valves, plumbing fixtures, etc. Because of the thickness of the walls and ends of a union potentially may not fit correctly and cause leaking.

westend
Explorer
Explorer
The flexible supply line is a good solution. It will isolate movement from the movable water supply piping to the rigidly fixed toilet. The addition of a shut-off valve would have you entered into the PHOF (Plumber's Hall Of Fame).
'03 F-250 4x4 CC
'71 Starcraft Wanderstar -- The Cowboy/Hilton

myredracer
Explorer II
Explorer II
Andonso wrote:
I went down to the local True-Value hardware store but all they have is the Twist-it connectors like the one from the first pic, which aren't NPT type used with RV toilets.

The Twist-it I think they're called is more of a compression type fitting that installs a connector to the Pex or hard plastic water hose.

While at the store I remember I had a piece of 1 foot stainless braided supply line with 1/2 inch connectors. The type you use for facets, etc.

Water supply line

1/2 inch union

For around 0.75 cents found a 1/2 inch plastic union.

Then using the union joined the supply line to the RV supply line and to the toilet. All the connections fit without any leaks. No need for plumber tape as water supply lines have their own gaskets.


Just make sure to keep an eye on it for leaks. I once tried an ordinary 1/2" valve (quality commercial grade too) and no matter how much teflon tape I used, couln't get it to stop leaking.

Andonso
Explorer
Explorer
I went down to the local True-Value hardware store but all they have is the Twist-it connectors like the one from the first pic, which aren't NPT type used with RV toilets.

The Twist-it I think they're called is more of a compression type fitting that installs a connector to the Pex or hard plastic water hose.

While at the store I remember I had a piece of 1 foot stainless braided supply line with 1/2 inch connectors. The type you use for facets, etc.

Water supply line




1/2 inch union



For around 0.75 cents found a 1/2 inch plastic union.

Then using the union joined the supply line to the RV supply line and to the toilet. All the connections fit without any leaks. No need for plumber tape as water supply lines have their own gaskets.

I think this method works better than using an elbow which is rigid and can't be moved around. The supply line from the floor is also rigid and has little movement unless you cut a larger hole in the toilet box the toilet sits on. The toilet is a new low profile Thetford China toilet, now sitting on a toilet box built into the RV.

myredracer
Explorer II
Explorer II
What you want is a Qest fitting, available at RV parts vendors including the internet and of course ebay & Amazon. Has a grey color. For an RV toilet should have a fitting with a cone washer due to the shape of the threaded male fitting they have. I don't think anything else will seal properly except for maybe a swivel fitting. A 90 degree bend looks like in the photo. Could also install an angle stop valve so you can shut off the flow to see into the tank, which is what I did - make sure to have the water flow in the correct direction. Qest fittings don't cost much.

The 3rd photo is the Shurflo elbow from Amazon. Does not appear to have a cone washer and probably has a plain flat washer, but *might* work okay. Cost is $7.01 USD on Amazon.com or you can pay $66.55 Can + shipping right here on Amazon.ca for the same thing!!

Andonso
Explorer
Explorer
DutchmenSport wrote:
Check with your local RV dealership parts store. Every RV dealership I've been to that has it's own parts store has these connections and parts for plumbing.


I would but the closest RV shop or big box store is over 30 miles away. Carries a few parts but mostly is a RV repair shop. Sometimes sells a few used RVs.

The one from Ace has some sort of flare connection.

I think this type will work, cost is $7.00 with shipping

https://www.freshwatersystems.com/p-6623-shurflo-244-3366-wingnut-swivel-nylon-elbow-12-fnpt-x-12-mn...

ksg5000
Explorer
Explorer
Take a picture and go down to any of the big box hardware stores - they should be able to fix you up with no problem - many use shark bite and Flair it connectors.
Kevin

DutchmenSport
Explorer
Explorer
Check with your local RV dealership parts store. Every RV dealership I've been to that has it's own parts store has these connections and parts for plumbing.

Andonso
Explorer
Explorer
Could not find any Watt fitting but did find this one on the Truevalue site that appears may work.

http://www.truevalue.com/catalog/product.jsp?productId=52276

Described as a Pipe Fitting, Male Elbow, 1/2 PEX x 1/2-In. MPT

I do have some of these fitting that are 3/8-inch. They use what appears to be a rubber gasket on the FPT (female) end.

Appears to be a 1/2-in MPT x 1/2-in FPT 90 deg. elbow? Anyway I think that's what is needed as seem to recall reading somewhere that the RV toilet uses NTP fittings.

Dutch_12078
Explorer II
Explorer II
Check at True Value or Ace Hardware for 1/2" CTS Watts or Sea Tech poly quick connect fittings. Flair-It and Qest also make poly fittings that will work as well.

Amazon has Watts fittings: Watts Quick Connect Fittings
Dutch
2001 GBM Landau 34' Class A
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2011 Toyota RAV4 4WD/Remco pump
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