Hot Tub Plumbing

General Plumbing Guidelines

RATING: ADVANCED

Most spa plumbing will consist of common PVC (polyvinyl chloride) plastic, either rigid or flexible varieties, in 11/2- or 2-inch (40- or 50-millimeter) diameter, referring to the interior diameter (the diameter of the pipe that is in actual contact with the water). Before we proceed to specific instructions on working with PVC, here are a few useful general guidelines.

Measure the pipe run carefully, particularly if you are repairing a section between plumbing that is already in place. In measuring, remember to include the amount of pipe that fits inside the connection fitting, usually about 11/2 inches (40 millimeters) at each joint.

When you are working on in-place plumbing, support your work by building up wood or bricks under the pipe on each side of your work area. This will prevent vibration as you cut, which can damage pipe or joints farther down the line. Also, unsupported pipe will sag and bind when you cut it. That is, as you cut, it pinches the saw blade, making cutting difficult—and straight, clean cuts impossible.

Threaded fittings are obvious and simple; however, leaks occur most often in these connections. The key is to carefully cover the male threads with Teflon tape and to tighten the fitting as far as possible without cracking.

Teflon tape "fills" the gaps between the threads to prevent leaking. Apply the tape over each thread twice, pulling the tape tight as you go, so that you can see the threads. Apply the tape clockwise as you face the open end of the male threaded fitting. If you apply the tape backward, when you screw on the female I t
fitting, the tape will "skid" off the joint. Try it both ways to see what I mean, and you will make that mistake only once!

Another method of sealing threads is to apply joint stick or pipe dope. These are odd names for useful products that are applied in similar ways. Joint stick is a crayon-type stick of a gumlike substance. that works like Teflon tape. Rub the joint force stick over the threads so that the gum fills the threads. Apply pipe dope the same way. The only difference is that pipe dope comes in a can with a brush and is slightly more PVC fluid than joint stick. The key to success with joint stick or pipe dope is to apply it liberally and around all sides of the male threaded fitting, so that you have even cover-you finally screw the fittings together. Some product will ooze out as you tighten the fittings, but that proves that you have applied enough.

I use Teflon tape because I know upon application that it is an even and complete coverage of the threads. Pipe dope or joint stick may not apply evenly or may bunch up when you are threading the joint together. If you do use dope or stick, be sure it is a non-petroleum-based material (such as silicone). Petroleum-based products will dissolve plastic over time, creating leaks.

When you are working with PVC pipe and fittings, tighten threaded fittings with a channel lock type of pliers of adequate size to grip the pipe. Using pipe wrenches usually results in application of too much force and cracking of the fittings. If you don't have pliers large enough for the work and must use pipe wrenches, tighten the work slowly and gently.

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