For R-422B (NU-22B), operating pressures are not fixed; they change based on the outdoor and indoor temperatures. Because it is a direct retrofit for R-22, its pressures will be very similar (typically running a few PSI lower).
R422B can be used to COMPLETELY replace R-22 refrigerant in new or existing R-22 residential and commercial air conditioning systems as well as non-flooded evaporator chillers. Cannot be added to R-22 unless fully evacuated and recharged with 422B.
R-422B should always be removed from the cylinder and charged into the system as a liquid.
In a properly functioning R-410A air conditioning system, the low-side (suction) pressure is typically 100 to 145 PSI, and the high-side (discharge) pressure ranges from 300 to 450 PSI.
R422D systems often face incorrect pressure readings and improper refrigerant charge issues. For a 2.5-ton York system using R422D at 90°F, typical high-side pressure ranges from 280-320 psi, low-side around 70-90 psi. Use a manifold gauge set to measure pressures accurately.
Recovery of R-422B requires a recovery cylinder with a service pressure of 260 psig minimum. National Refrigerants, Inc. * Capacity loss will be greater in high ambient temperatures.
Technically no, R-422D is not a true "drop-in" replacement, but it is a widely used retrofit refrigerant. It cannot be mixed with R-22, and retrofitting requires fully recovering the old refrigerant, evacuating the system, and making minor adjustments.
Incorrect pressures can signal low refrigerant charge, airflow restrictions, dirty coils, or more severe issues. For example, high discharge pressure might indicate overcharging, while low suction pressure might signal a leak or restriction.
R-410A is currently being phased down rather than fully banned, with the production of new R-410A equipment already banned. The remaining supply will be gradually reduced by 85% through 2036.
Simply put, it means you should never set your thermostat for a temperature more than 20 degrees cooler than the outside air. Why not? Most air conditioning systems can only handle a 20-degree difference between the outside and inside air temperatures.
R-422B is compatible with all standard compressor oils: Mineral Oil (MO), Alkylbenzene (AB), and Polyolester (POE). Because it is compatible with existing mineral oil, it is a highly popular drop-in replacement for R-22 systems.
Can you mix R422B with R-22? No, mixing R422B with R-22 is not recommended. The two refrigerants have different chemical properties, and mixing them can lead to reduced performance and potential system damage.
The 3-minute rule is a simple but important guideline: wait at least three minutes after turning your air conditioner off before turning it back on. That short pause gives the refrigerant pressure in the system time to equalize.
R-422B is a non-ozone-depleting refrigerant compatible with all standard oils, equipment components, and materials used in R-22 systems. R-22 systems that convert to R-422B see a minimal capacity loss of less than 10%.
Virgin refrigerants with a GWP equal or greater than 2,200 are banned starting January 1st, 2025. This would affect refrigerants such as R-422A, R-422B, R-422C, R-422D, R-428A, R-438A, R-404A, R-407A, R-408A, R-507 currently used in HVAC-R.
Mixing refrigerants is not recommended.
Yes, R-422B (often sold as NU-22B) is a "near" drop-in replacement for R-22 in most residential and commercial air conditioning and refrigeration systems. It is designed to safely mimic R-22 operating pressures without requiring an expensive, time-consuming compressor oil change.
A2L refrigerants, the new refrigerants for 2026, will replace R-410A in new systems. A lot about A2L refrigerants is explained in their name: The “A” means low toxicity. The “2L” is a safety classification, indicating it is mildly flammable.
If you're interested in learning how to refill R22 in your air conditioner, it is important to know that this is not something a homeowner can do on their own. Due to complexity, safety concerns, training and licensing required we do not recommend doing this without having a trained professional onsite.
At 73°F ambient, R22 system condenser pressures typically range: high side around 150-175 psi, low side near 60-70 psi. Variations may indicate refrigerant charge issues or airflow restrictions. Use manifold gauges to measure pressures accurately.
✔ Charge the refrigerant as a liquid (not vapor) to ensure proper blend ratios. ✔ Avoid mixing with other refrigerants. ✔ R-422B is non-toxic and non-flammable, but misuse can still cause harm. ✔ Follow EPA Section 608 guidelines for recovery and disposal.