25LB R407C (R-407C) Refrigerant Gas | 10 Cylinders

10 cylinders at 25 lb each makes 250 lb of refrigerant. Converting a direct-expansion system off R-22 is a day of work rather than a top-up: recover the old charge, change the compressor oil over to polyolester, flush or replace what the survey says needs it, pull a proper vacuum, then weigh in the full charge. Running short mid-job means a return trip, so work your charge weights out against that 250 lb before you commit to it.

Glide is the thing to work around. Being a zeotropic HFC blend, it has to go in as liquid: inverted cylinder, or through a metering device into the suction side with the compressor running. Draw vapour instead and the lightest fraction leaves first, which shifts the mix left in the cylinder. Read superheat off dew point and subcooling off bubble point. Weigh the charge; pressure readings by themselves will mislead you.

Chlorine-free, unlike the R-22 it was brought in to replace in direct-expansion air conditioning and medium-temperature refrigeration. Head pressure sits somewhat higher than R-22, so look hard at the condenser and the controls before quoting a conversion. Retrofits want polyolester oil; mineral oil will not come back to the compressor. After a leak, recover and recharge by weight rather than topping up, because what is left in the system has shifted.