25LB R407A (R-407A) Refrigerant Gas | 10 Cylinders

Stock at this depth suits a crew that services its own plant. If the engineer on shift answers the warm case on a Friday night, the store room is doing work a distributor would otherwise do. How far a pack this size goes depends on your charge sizes, your leak history and how much you keep in-house — read it against your own service records. Weight like this also wants space and hands arranged before it arrives.

R-407A is a zeotropic HFC blend — R-32, R-125 and R-134a put up as one service gas. It came in for direct-expansion commercial plant built around R-22 and R-502, and it still earns its keep in supermarket racks, display cases, walk-ins and cold stores. Charge it as liquid. Draw vapour off the cylinder and the mixture left behind drifts off specification. Take superheat and subcooling from the bubble and dew point columns of a blend-specific chart, never from one saturation figure.

Oil matters on a blend like this. HFC service gas is generally a polyolester application, and mineral oil does not return reliably with it — confirm the oil spec for the system before you top it up. Then sort out where the cylinders live: upright and restrained, cool and ventilated, clear of stairwells and exit routes, full cylinders kept apart from empties, and inside whatever your fire code allows for compressed gas in one room. Heavier than air, the gas displaces oxygen in a pit or a closed plant room.