JAN/FEB 2026 RETA Breeze

JUSTIFYING THE AMMONIA DELIVERY

Before you add an ammonia charge to the HPR, be certain there is no ammonia present in another part of the system.

By Brian Chapin & Victor Dearman, Jr., CIRO, CRST

T he issue: A facility with an ammonia refrigeration system which uses a High Pressure Receiver (HPR) as their main storage vessel notes that their HPR level is rather low, and they are considering ordering some ammonia to get back to the levels they “used to have.” The thinking is that they need to add to the ammonia charge to make up for ammonia that was lost over time. Before you go too far, a good question to ask is: Did I lose ammonia? Or, is it just some where else in my system? A common failure is not understanding inventory control and manipulating levels until the facility finds itself impacting production due to extremely low liquid levels. WHAT IF YOU DIDN’T LOSE IT? Did you add equipment without your Management of Change (MOC) addressing if this required

an inventory adjustment? Did you change the recirculator vessel levels, which make the HPR look low even though the ammonia is still out in the system? Has someone been mucking with the HXVs or TXVs, so you are “brining” coils? These are common issues, but the most likely culprit is seasonal variation . Conversely, has anyone purposefully throttled heat HXVs to starve equipment in an effort to transfer liquid back to the HPR? These are reasons why there are inventory where it should be. In fact, look up 29CFR1910.119(f)(1) (iii)(D), “ Quality control for raw materials and control of hazardous chemical inventory levels. ” If it’s August in Texas, it’s likely that your system is running about as hard as it will ever run. That means that the NH3 isn’t just hanging out in your vessels, but out in the various heat upper and lower limits of operation that help keep

Ammonia receiver tank. Photo courtesy EVAPCO.

22 RETA.com

JANUARY/FEBRUARY 2026