Arkansas HVACR NewsMagazine March 2022

HVACR NewsMagazine March 2022

Tech News

· Read the manufacturer’s literature to learn the recommended foot-pound torque. Some manufacturers data will only be in metric. Make sure to have a torque wrench with heads that include standard and metric. · Remember that the torque value may vary from manufacturer to manufacturer and it will vary depending on the size of the copper tube, flare adapter, and flare nut size. · An adjustable head torque wrench can be used when working on systems with many flare nut sizes. This allows you to speedily adjust your torque wrench.

so that you do not over-pressurize a system. · If a leak is detected, use a non-corrosive bubble leak detector on the exposed joints in order to find the leak or use an ultrasonic leak detector. · Do a pressure test before doing the vacuum procedure, otherwise if there is a leak, you will pull in the humid air surrounding the outside of the leak spot into the tubing. · When performing a vacuum, pull the vacuum down below 500 microns and perform a standing vacuum test. Try to target at least 200-300 microns while the vacuum pump is running, before performing the standing vacuum test. Here is a video on vacuuming a mini-split ductless unit and breaking the vacuum with refrigerant from the bottle: https://youtu.be/k9uohbYDuRs Here is a video showing the 10 reasons why mini-split flares may leak: https://youtu.be/iLTMlIT6Qvg

Problem #10: The Pressure Test·

About the Author: Craig is the owner of AC Service Tech LLC and the Author of the book “Refrigerant

If you pressure test the system at a low PSI, a leak may not show up until you run the system in heating mode. · When using a compound manifold gauge set, you may have to let the pressure test sit on there longer because the incremental changes in a compound gauge are very small. · A leak shows up quicker when using a digital manifold gauge compared to a compound manifold gauge set because the digital display indicates changes in tenths of a PSI. · You want to pressure test the system below the max design pressure of the unit. Follow the manufacturer’s installation literature for pressure testing

Charging and Service Procedures for Air Conditioning”. Craig is a licensed Teacher of HVACR, Sheet Metal, and Building Maintenance in the State of New Jersey of the USA. He is also an HVACR Contracting Business owner of 16 years and holds an NJ HVACR Master License. Craig creates educational HVACR articles and videos which are posted at https://www.acservicetech.com & https://www.youtube.com/acservicetechchan nel & https://www.facebook.com/acservicetech/