Can I use Teflon tape or something else??

Hello,

I am in the middle of installing a chemical injection system to reduce the pH of my home's well water. The instruction sheet for the static inline mixer (a PVC part made by Johnson Screens) says, "Pipe joint compounds and Teflon based products may react with PVC to cause stress cracks."

I had interpreted that to mean "use nothing". That's a little odd. I usually use Teflon tape on plastic joints.

Well, the three joints leak and had them pretty tight, so I'm going to need to put something on them. What do you recommend?

Thanks in advance for any advice you'd have!
Art
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Joints

They are referring to pastes and liquids which can damage PVC if they are not compatible with it. Teflon tape, and many pastes are PVC compatible.

That's excellent! Thanks.

Threaded plastic fittings are diverse depending on the molecular structure of the polymer. Often they are attacked by other petroleum based products, hence the warning. Sometimes it is best to use nothing at all, such as when you are threading a 'hard' polystyrene sprinkler head onto a 'soft' polyethelyne nipple. The pliability provides the seal. In most chemical injection systems you see threaded fittings made of a 'hard' polyvinylchloride (PVC). The threads have no pliability and can have a tendency to leak. Teflon Tape has no properties that could compromise the molecular structure of the plastic, and is excellent in adding a bit of 'pliability' to the threaded surfaces to create a good seal. Teflon Tape is the way to go.

I just cleaned out my clorine injector on my chemical unit which when first installed didn't have any leaks but after taking it apart and cleaning it it started a small drip from one of the threads. I used a good quality teflon tape and everything sealed perfect.

Alex

Either/or is fine as long as the pipe dope is PVC compatible. This would be listed somewhere on the labeling.