Replacing toilet supply valve, new one leaking!

[sosnpk]

We just purchased a 1946 colonial and have started getting the place up and running again. I am replacing all the hardware on an upstairs toilet.

To start I shut off the water supply at the toilet but still heard a trickle of water running through it, this indicated to me that the toilet supply valve was bad. When I took the valve to Lowe's to compare I found it was a 5/8 inlet with 3/8 out. The strange thing about the valve was that it was female but then attached to a rod threaded on both ends and tied into the supply line via a threaded fitting attached to the supply line in the floor.

So the valve is female but made male by the pipe extension. The supply line is female.

I decide instead to purchase a male inlet valve and attempt to screw it into the supply line in the floor. I wrapped the threads with teflon tape and attempted to tighten the valve into the floor, the valve only turns about 3/4 of the way by hand into the supply line fitting. When I turned on the water to the toilet the valve leaked where I had connected to the supply line fitting.

I am sorry if the terms I used above are confusing and am willing to help clarify. Did I purchase the wrong valve? Should I just look into rebuilding the original valve for time being?

Any help appreciated, the water is currently shut off at the main until this is addressed.

[LazyPup]

The first step is to determine what kind of pipe you have in the wall.

The house is circa 1946 so if the piping is original to the house it will most likely be either galvanized iron pipe, or it may be copper. (Copper pipe was first introduced for a relatively short period before World War II, but during the war all supplies of copper were taken up by the government for military purposes, it was re-introduced into the building trades very early after the war so if your house was on the cutting edge of high tech at the time it could have original copper piping.)

If your pipe is galvanized iron pipe all joints will be threaded joints using the NPT (National Pipe Taper) threading system. NPT threads are cut with a taper so that the tighter you screw the fitting in, the tighter the joint. NPT threads also require a thread joint compound to effect a proper seal. You may use either 'Thread Dope" or the appropriate PTFE(teflon) tape.

Be careful when using teflon tape because the ASTM (American Society of Testing & Materials) has now listed a new set of standards for thread tapes. The common little blue & white rolls of single density teflon tape that we find in the hardware stores is no longer considered suitable for potable water lines greater than 1/4" diameter.

For potable water supply fittings the proper tape is "RED-Triple Density" teflon tape, and it is only approved when 3 full wraps are applied under tension in the direction of the thread turn. (Most of the Lowes, Home Depot and Menards stores I have been in do now carry the "Red Triple Density" tape. You will find it in a red plastic roll and the tape itself has a light pinkish color. The triple density tape is typically about $2.98 a roll which seems expensive when compared to the $.98 rolls of the single density, but take my word for it, it is worth every penny.

If you have copper pipe there are three possible methods of attaching the valves.
1. The copper pipe can be fitted with a thread adapter which converts it to NPT thread, then you can use a MIP(Male Iron Pipe) or FIP (Female Iron Pipe) threaded supply valve.
2. The valve can be soldered directly on the copper pipe. In this case the valve would be listed by the size of the copper pipe, typically 1/2" and would be listed as a solder or "sweat connection".
3. The third option is to mount the valve on the end of the copper by means of a compression mount. Compression fittings can be a bit confusing because compression fittings are technically "Tubing Fittings" rather than "Pipe Fittings".
Pipe fittings are sized by the inside diameter of the pipe (ID) while tubing fittings are sized by the Outside Diameter (OD). by example, if you have 1/2" copper pipe the pipe is sized by its inside diameter and the solder fittings are made to fit the od of the pipe but they are listed by the ID of the pipe they fit. Thus the solder fittings for 1/2" copper pipe will be listed as 1/2" copper fittings.
When selecting a compression mount valve to be used on 1/2" copper pipe we must select a fitting that equals the outside dimension of the pipe. (1/2" copper pipe has an ID of 1/2" but the OD is 5/8"). Thus if you desire a compression mount angle stop or line stop to be applied directly to the copper pipe you would need a 5/8compression mount. (Some valves are listed as 1/2" copper pipe & 5/8Compression).

When cutting copper pipe it is essential that we use a good quality copper tubing cutter. Cutting copper by any other means will ultimately leave the pipe walls distorted out of round and they will never properly solder or seal by means of a compression fitting.

After cutting copper pipe the end of the pipe should be lightly reamed to insure there are no burrs on the end of the pipe. (Burrs cause a serious increase in the velocity of flow and result in erosion of the pipe wall, in fact, copper piping must be carefully laid out to insure the velocity of flow does not exceed 8 feet per second, otherwise you can have serious premature failure of the pipe wall.

When installing compression fittings on copper pipe we must be sure to clean the surface of the pipe with emery cloth in the same manner as when we plan to solder the pipe. This will insure their is no debris on the pipe wall that could interfere with the sealing process.

When installing compression fittings it is important to use two wrenches, one to hold the fitting firmly in place while the second wrench is used to tighten the compression nut to effect a good seal.

[sosnpk]

More than likely the pipe is galvanized, how should I handle this connection?

[sosnpk]

I went to a plumbing supply store over lunch and showed them the valve. They gave me a brass nipple to insert between the valve and the galvinized connection. Does this sound like the correct piece? The original valve had a chrome nipple between the valve and the supply line.

Will the brass piece require the use of the triple density teflon tape you mentioned above? Should the nipple be fitted to the supply line first and then the valve added or should it be done the opposite way?

Thanks for your assistance with this!

[Phelps]

Brass is a compromoise metal for guarding against corrosion that occurs from mating dissimilar metals. Copper to galvanized is worse. Why didn't you get a chrome one?

If you don't want pipe wrench jaw prints sunk into you nipple extension, assemble both pieces with the male threads all taped up first. (I like to tape from the inner to the outer because in theory you will not be tightening threads into the edge of the tape.) Instead, by wrapping the tape from inside to outside, the threaded fitting will go over the tape edges. Then, if you can, just tighten the valve with an open end or crescent wrench on the place on the valve for doing so, and the extension nipple will automatically end up tightening as well. If you tighten the two at once, in this fashion, you will notice that the 'seems to be getting tight' will last twice as long. I like to retighten a little further after stopping the first time to allow for expansion from the heat generated when you tighten. But don't ever go bonkers and overtighten. With experience, you recognize that perfect squish feeling when you tighten like a nut to a bolt.

[LazyPup]

It is true that the codes prohibit directly coupling copper pipe to ferric iron pipe, fittings or vessels however in this application their is no concern. Even if the pipe in the wall is galvanized iron pipe (ferric iron pipe) the nipples are brass or bronze which is listed as an approved transition material, and even if that were not the case, the valves themselves have a brass body which may be connected directly to galvanized iron pipe.

With the singular exception of the chrome plated PVC shower arms, ALL chrome plated nipples are brass or bronze nipples, because in order to chrome plate they need to have a copper, brass or bronze base metal for the chrome to adhere to. Therefore the inclusion of chrome in this application is purely for aesthetics and has no mechanical advantage. In fact, in some instances chrome can interfere with thread cutting and the use of chrome plated fittings requires considerably more attention to detail than when using brass or bronze.

When applying PTFE(teflon) tape, per ASTM specifications you must begin the wrap at the cut end of the pipe and rotate the tape under tension in the direction of the treads moving inward on the pipe until you have three full wraps of tape at all points. (Personally I much prefer to use pipe dope on all NPT threads.)

When installing a nipple close to a finish wall you can begin by inserting the nipple into the female thread in the wall, then grip the nipple close to the wall by first wrapping the nipple with a wet rag, then gripping it close to the wall with a pair of channel lock pliers and tighten as firmly as you can. If you would carefully any scratches that you may get on the finish of the nipple should be close enough to the wall that they would later be covered by the trim escutcheon.

After you have the nipple tight in the wall, remove the rag and slide the trim escutcheon into place, then screw the valve on the outer end of the nipple. You can then turn the valve by gripping the valve body with a smooth jawed wrench such as an adjustable crescent wrench. Continue turning the valve until it is tight and in the final position with the side outlet in the upright position. If it is not ligned up you must go around one more turn. Absolutely do not back a threaded joint up to align the valve because backing up a threaded connection will almost always introduce a leak.

[sosnpk]

I performed the repair last night exactly similar to Lazypup's instructions in his last post, used the pipe dope he has mentioned in another topic. The nipple fit well and I tightened it down as much as I could, the valve went on smoothly and I was able to line it up perfectly. No leaks and everything appears to be in good order.

Thanks for all your help with this and look forward to reading more of your posts.

[Phelps]

When applying PTFE(teflon) tape, per ASTM specifications you must begin the wrap at the cut end of the pipe and rotate the tape under tension in the direction of the treads moving inward on the pipe until you have three full wraps of tape at all points. (Personally I much prefer to use pipe dope on all NPT threads.)

Why does ASTM specify to wrap tape in said fashion?