Makawi R407C Refrigerant
Makawi R407C Refrigerant
Makawi R407C is a zeotropic blend of the hydrofluorocarbons R-32, R-125 and R-134a, formulated to match the operating characteristics of R-22. It does not harm the ozone layer. Because its pressures and capacities are close to those of R-22 it can be used in existing R-22 systems provided the appropriate changes are made — and that is the key difference from R410A.
Properties and performance
Its ASHRAE safety group is A1. As a zeotropic blend it has a pronounced temperature glide: evaporation and condensation take place over a range rather than at a single temperature. For that reason it should not be used in equipment with flooded evaporators or in centrifugal chillers; it suits direct expansion (DX) systems.
Lubricant
POE oil is used. In retrofitted R-22 systems the existing mineral or alkylbenzene oil must be brought below 5% through an oil change procedure, otherwise oil return is compromised. New R407C equipment arrives filled with the oil recommended by its manufacturer.
Charging
As a zeotropic blend it must always be charged in the liquid phase; vapour charging causes the components to separate. Where it must be fed as vapour, a valve that flashes the liquid is fitted to the charging line.
Converting an R-22 system — the sequence
- Record the system's current performance, oil type and operating values; carry out a leak check and identify the repairs needed.
- Recover the existing refrigerant (never vent it) and weigh it.
- Drain the oil from the compressor crankcase and the accumulator, recording the quantity, and add the same quantity of manufacturer-approved POE oil.
- Recharge with the recovered R-22, run the system for at least one hour, then recover again and measure the residual ratio in the oil. Repeat until residual mineral oil is below 5%.
- Change the filter drier, repair any leaks, evacuate the system below 500 microns and confirm that the vacuum holds.
- Charge R407C as liquid. Start the initial charge at roughly 90% of the R-22 charge and top up to 95% if needed.
- Adjust the expansion valve and/or charge quantity for the required superheat, and monitor the compressor oil level.
- Label the system with the refrigerant and oil type it now contains.
Technical data
| Composition | HFC-32 (CAS 75-10-5) + HFC-125 (CAS 354-33-6) + HFC-134a (CAS 811-97-2) |
| Average molecular weight | 86.2 g/mol |
| Normal boiling point | −43.4 °C (−46.1 °F) |
| Critical temperature | 86.2 °C (187.2 °F) |
| ASHRAE safety group | A1 (low toxicity, non-flammable) |
| Ozone depletion potential (ODP) | 0 |
| Lubricant | POE (polyol ester) |
| Packaging | 11.35 kg (25 lb) single-use steel cylinder |
Where it is used
Residential and commercial air conditioning, direct expansion refrigeration systems, chillers without flooded evaporators, and the retrofit of existing R-22 systems.
Storage and safety
- Store cylinders upright in a cool, ventilated area, away from direct sunlight and temperatures above 50 °C.
- Liquid refrigerant causes frostbite on contact with skin — wear gloves and eye protection.
- The vapour is heavier than air and displaces oxygen in confined spaces, creating a risk of asphyxiation. Ventilation is essential indoors.
- Never vent to the atmosphere: recover the refrigerant with a recovery unit during service and decommissioning.
- Read the product safety data sheet (SDS) before use.
Contact the Lapin team for cylinder quantities, lead times and current pricing.