Leaking (Bypassing) Valves

We had a class with our refrigeration techs and the topic of leaking and bypassing service “angle” valves and ball valves came up. One of the techs pointed out that most valves recommend loosening the top nut on ball valves and the packing nut on angle valves before turning the stem for maximum longevity of the valve and ease of turning.

It is worth noting that on angle valves you need to be careful not to back out the packing too far, just loosen it and then retorque it down when finished with use.

Mueller also points out that when brazing in packed service valve the valve should be mid-seated to prevent the seal from sticking together in either the open or closed position as well as keeping a wet rag wrapped on the valve to keep the valve temperature below 300 degrees.

These illustrations come from Mueller refrigeration Ball valves and angle valves

— Bryan

Related Tech Tips

Tech Question - Why Do ECM Motors Trip a GFCI?
This question was submitted on the site in response to the recent GFCI tip. It's a good question with several possible answers. What do you think? Hey Bryan, I have had a few instances where we are firing off a furnace in a new build with a temporary power pole outside with gfci outlets installed […]
Read more
Powered Attic Ventilation
When I first started in the trade, I used to advise customers with hot attics to install powered attic ventilators (PAVs) to “suck” that hot air out of the attic. It just made sense to me at the time; if the attic is hot, get the hot out! When I started learning more about design, […]
Read more
Lifting Techniques Part 5 - Really HEAVY Stuff
This is Part 5 of a series by Senior Refrigeration Tech (and prolific writer) Jeremy Smith. Pay attention to this one, folks. I know rigging and safe lifting practices may be boring to some of you, but it could very well save your back or your life. Disclaimer This article is written by a technician […]
Read more

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

loading

To continue you need to agree to our terms.

The HVAC School site, podcast and daily tech tips
Made possible by Generous support from