DISCLAIMER: HVAC School is NOT an official OSHA safety training resource! Although we provide safety tips in good faith, our website is not a substitute for safety training from an authorized OSHA training source.   When most people think about respiratory devices, their minds probably jump to soldiers wearing gas masks in warfare, hazardous waste […]

As HVAC/R Technicians, we use tools and instruments to take measurements every day. In fact, 90% of our job could not be done efficiently without some kind of measurement.  “How do we measure?” “With what instruments?” “How accurate are these measurements?” These are all questions a thoughtful technician should ask before spending money on a […]

I don't do much in the way of “rack” refrigeration. However, I recently had a conversation with experienced rack refrigeration tech Jeremy Smith, and he got me thinking about EPR valves. I've heard EPR (evaporator pressure regulator) valves called suction regulators or hold back valves. In essence, they hold back against the suction line to […]