HVAC Procedure and Performance Guide

TASK: Connect pipe using threaded joint

Training for this procedure can be found in these courses:

                         131 – Oil Heat   and  101 – HVAC Fundamentals


Pipe must be cut square and deburred and must be threaded with required number of perfect threads and three vanishing threads.  Thread sealant must be applied to pipe so as not to enter inside of pipe when joint is made.  Joint must be made up on perfect threads only without leaking.  Vanishing threads must not enter into joint.  Applicable safety procedures must be followed.


  1. Review job specifications.
  2. Determine type and size of pipe and joint to be made.
  3. Collect tools, equipment and materials.
  4. Put on safety and protective equipment and apparel.
  5. Cut pipe:

a. Steel pipe:

1) Place pipe in pipe vise or pipe cutter threader and cut to length.

2) Remove cutter burrs from pipe using pipe reamer.

b. Plastic pipe:

1) Cut pipe to length with hacksaw or plastic pipe cutter.

2) Remove cutter burrs from pipe using file or knife.

6. Thread pipe.  (Note:  Do not thread PVC or CPVC pipe less than Schedule 80.  Do not thread ABS or PE plastic pipe.  Do not use cutting oil with plastic).

a. Select dies and insert in threading tool.

b. Position threader on end of pipe and adjust guides to contact.

c. Thread pipe and remove threader. (Note:  Do not over-thread).

d. Clean all chips from outside and oil and debris from inside of pipe.

7. Make joint with fitting or component:

a. Determine special requirements for pipe thread sealant.

b. Apply pipe dope, sealant or thread tape to pipe threads, leaving first two threads bare.

c. Make up fitting on pipe as tightly as possible by hand. Use wrench and make fitting up two to three more threads.

8. Repeat procedure until required number of joints are made.

9. Check joint for leaks.

10. If joint leaks, tighten if possible and retest.  (Note:  Vanishing threads must remain exposed).  If joint continues to leak, make up new joint using new materials, repeating Steps 5 through 7.

11. Remove safety and protective equipment and apparel.

12. Gather tools, equipment and leftover materials, and leave work site clean.