R454B does not have one universal “normal operating pressure.” Its saturation pressure is defined by temperature, but actual suction and discharge pressures depend on the equipment, evaporating and condensing conditions, load, airflow or water flow, control state and measurement location. Use the pressure-temperature data below to convert pressure to saturation temperature; use the exact equipment manufacturer’s charging and commissioning procedure to judge operation.
R454B is a zeotropic blend of 68.9% R32 and 31.1% R1234yf. Chemours publishes an AR5 GWP of 467 and an AR4 GWP of 466. Its ASHRAE safety classification is A2L. It is intended for equipment specifically designed and approved for R454B; it is not a field drop-in replacement for R410A.
R454B PT Chart: Bubble and Dew Data
The following selected points are transcribed from Honeywell’s official Solstice 454B technical data sheet. Honeywell publishes absolute pressure in kPa and the corresponding liquid bubble and vapor dew temperatures in degrees Celsius. The PSIG column is a calculated convenience at standard atmospheric pressure:
PSIG = (kPa absolute ÷ 6.894757) − 14.696
| Pressure (kPa absolute) | Pressure (PSIG, calculated) | Liquid bubble temperature (°C) | Vapor dew temperature (°C) |
|---|---|---|---|
| 200 | 14.3 | −35.93 | −34.84 |
| 400 | 43.3 | −18.67 | −17.48 |
| 600 | 72.3 | −7.21 | −5.96 |
| 800 | 101.3 | 1.62 | 2.92 |
| 1,000 | 130.3 | 8.92 | 10.24 |
| 1,200 | 159.4 | 15.20 | 16.52 |
| 1,400 | 188.4 | 20.73 | 22.06 |
| 1,600 | 217.4 | 25.70 | 27.03 |
| 1,800 | 246.4 | 30.22 | 31.54 |
| 2,000 | 275.4 | 34.38 | 35.69 |
| 2,200 | 304.4 | 38.24 | 39.54 |
| 2,400 | 333.4 | 41.85 | 43.12 |
| 2,600 | 362.4 | 45.24 | 46.48 |
| 2,800 | 391.4 | 48.44 | 49.64 |
| 3,000 | 420.4 | 51.46 | 52.64 |
| 3,200 | 449.4 | 54.34 | 55.48 |
| 3,400 | 478.4 | 57.09 | 58.18 |
| 3,600 | 507.4 | 59.71 | 60.75 |
| 3,800 | 536.4 | 62.22 | 63.21 |
| 4,000 | 565.5 | 64.64 | 65.56 |
Data basis: Honeywell Solstice 454B technical data sheet. Calculated PSIG values are rounded to one decimal place. Check the current refrigerant-manufacturer data and calibrated instrument before service work; this selected table is not a substitute for the equipment service manual.
Which PT Value Is Used for Superheat and Subcooling?
- Superheat: use the vapor dew saturation temperature corresponding to measured suction pressure, then compare it with the measured suction-line temperature at the specified location.
- Subcooling: use the liquid bubble saturation temperature corresponding to measured liquid pressure, then compare it with the measured liquid-line temperature at the specified location.
- Static equalized pressure: after the system has been off long enough to equalize and reach a common temperature, pressure should correspond approximately to the refrigerant saturation condition at that actual refrigerant temperature. Static pressure does not prove correct charge.
Because R454B is a blend, bubble and dew temperatures differ. Using the wrong side of the PT relationship introduces an error into superheat or subcooling. Do not mix absolute pressure, gauge pressure and bar units.
What Should R454B Suction and Discharge Pressures Be?
There is no single correct pair of pressures for every R454B chiller, heat pump or air-conditioning unit. A PT chart gives saturation relationships, not target running pressures. The same refrigerant can operate at very different pressures in a comfort-cooling unit, process chiller, reversible heat pump or low-temperature circuit.
| Input needed | Why it changes the pressure reading |
|---|---|
| Equipment model and operating mode | Defines the refrigerant circuit, heat exchangers, controls and approved pressure envelope. |
| Entering and leaving fluid or air temperatures | Determines the heat-exchanger duty and expected evaporating or condensing condition. |
| Water flow or airflow | Low flow can change heat transfer, superheat, saturation condition and protection response. |
| Load and compressor capacity state | Staging, unloading and variable-speed operation change mass flow and pressure. |
| Ambient or condenser-water condition | Directly affects heat rejection and condensing pressure. |
| Expansion-device and control state | Valve position and control target affect evaporator feed and superheat. |
| Measurement location and instrument accuracy | Pressure drop and sensor error can make two valid measurements differ. |
Diagnose the system from the manufacturer’s operating data together with pressures, line temperatures, superheat, subcooling, load, flow, electrical data, alarm history and visual inspection. Adding refrigerant because a pressure “looks low” can create an overcharge and does not correct flow, fouling, sensor, valve or compressor faults.
Verified R454B Physical and Safety Properties
| Property | Published value | Basis |
|---|---|---|
| Composition | 68.9% R32 / 31.1% R1234yf by weight | Chemours Opteon XL41 |
| Molecular weight | 62.6 g/mol | Chemours product bulletin |
| Normal boiling point | −50.5 °C (−58.9 °F) | 1 atmosphere |
| Critical temperature | 78.10 °C (172.6 °F) | Chemours product bulletin |
| Critical pressure | 5,266.9 kPa absolute (763.91 psia) | Chemours product bulletin |
| Saturated-liquid vapor pressure at 25 °C | 1,570.8 kPa absolute (227.83 psia) | Chemours product bulletin |
| Heat of vaporization at normal boiling point | 316.28 kJ/kg (136.07 Btu/lb) | Chemours product bulletin |
| ASHRAE safety classification | A2L | Chemours bulletin citing ASHRAE Standard 34 |
| GWP | 467 (AR5); 466 (AR4) | 100-year values published by Chemours |
| Ozone depletion potential | 0 | CFC-11 = 1 basis |
| LFL at worst case of formulation | 11.5% by volume | Chemours product bulletin test basis |
Property values must retain their stated test and assessment basis. GWP values should not be compared unless the same assessment basis is used.
R454B vs R410A
| Item | R454B | R410A | Engineering implication |
|---|---|---|---|
| Safety class | A2L | A1 | R454B equipment, installation and service procedures must address A2L requirements. |
| GWP, AR5 (AR4) | 467 (466) | 1,924 (2,088) | Always state the assessment basis. |
| Saturated-liquid pressure at 25 °C | 1,570.8 kPa abs | 1,657.4 kPa abs | Pressures are similar but not identical; use the correct PT data and controls. |
| Drop-in replacement | No. Do not mix the refrigerants or convert equipment unless the original equipment manufacturer provides an approved conversion procedure and all applicable code requirements are met. | New purpose-designed equipment is the normal selection route. | |
| Capacity and COP | No universal percentage applies. | Compare complete equipment at the same published rating conditions. | |
R454B is one lower-GWP option used in new equipment. Regulations vary by country, product category, date and application. The U.S. EPA Technology Transitions program establishes sector-specific restrictions and has been amended; it does not make R454B the single mandatory replacement for every system.
Can an R410A System Be Retrofitted to R454B?
Do not treat R454B as a field drop-in. R410A equipment was not necessarily designed, listed or approved for an A2L refrigerant. A conversion review must address compressor and lubricant approval, valves, heat exchangers, pressure controls, relief devices, electrical components, charge limits, detection or ventilation requirements, labeling, service tools, local code, listing and warranty.
Many R410A systems already use POE lubricant, so an oil change alone does not make a conversion acceptable. Without an OEM-approved conversion path, replacement with purpose-designed R454B equipment is the safer procurement basis.
R454B Safety and Service Boundaries
- Work must be performed by personnel qualified for refrigerants, electrical systems and applicable A2L procedures.
- Follow the exact equipment manual and local code for charge limits, room size, detection, ventilation and ignition-source control.
- Use recovery machines, leak detectors, vacuum equipment, scales, hoses, gauges and cylinders approved by their manufacturers for the refrigerant and applicable A2L work.
- Never vent refrigerant, mix recovered refrigerants or bypass safety devices.
- After repair, follow the OEM procedure for leak testing, evacuation, weighed charge, commissioning and documented verification.
This page is a technical reference, not a charging instruction or substitute for the equipment service manual.
GESON R454B Chiller Supply
GESON can supply new chillers using R454B where the selected model, compressor envelope, cooling duty, fluid temperature, heat-rejection condition, destination-market requirements and written technical scope are suitable. R454B availability is not universal across every capacity or temperature range.
Applicable units can be supplied with CE and ISO documentation within the exact written model and certificate scope. Standard configurations have a fixed lead time of 30 working days after the technical specification, drawings, payment and other written conditions are agreed. Applicable units have a 40,000-hour trouble-free operating capability within approved application, installation, operation and maintenance conditions; the model-specific scope must be confirmed in writing.
R454B Chiller RFQ Data
- application and process being cooled;
- required cooling load and load profile;
- entering and leaving fluid temperatures;
- required flow and system pressure drop;
- fluid type and glycol concentration;
- maximum ambient or condenser-water conditions;
- power supply and installation location;
- applicable code, room or area constraints and destination country.
GESON will state capacity, power input and COP only at the agreed rating conditions. Refrigerant, compressor configuration, materials, controls, documentation and service scope are confirmed in the written quotation.
R454B FAQ
What is the normal operating pressure for R454B?
There is no universal normal suction or discharge pressure. Use the equipment manufacturer’s operating data together with load, temperatures, flow or airflow, control state, superheat and subcooling.
How is the R454B PT chart used?
Match measured pressure with saturation temperature. Use vapor dew temperature for superheat and liquid bubble temperature for subcooling. Confirm pressure units and use calibrated instruments.
What is R454B pressure at 25 °C?
Chemours publishes a saturated-liquid vapor pressure of 1,570.8 kPa absolute, or 227.83 psia, at 25 °C. That is a saturation property, not a universal running discharge pressure.
Is R454B a direct replacement for R410A?
No. R454B is A2L while R410A is A1. Do not mix them or convert equipment without an OEM-approved procedure and compliance with all equipment, listing and local-code requirements.
Does R454B always have better COP than R410A?
No universal COP improvement can be stated. Compare complete equipment at identical fluid temperatures, ambient or condenser conditions, flow, load and rating standards.
Can GESON supply an R454B chiller?
Yes, subject to model, duty, fluid temperature, heat-rejection condition, destination requirements and written technical confirmation. Exact capacity, efficiency, certification and configuration are stated in the quotation.
What information is needed for R454B chiller selection?
Provide the application, load, entering/leaving fluid temperatures, flow, pressure drop, fluid and glycol concentration, ambient or condenser-water conditions, power, installation location and destination country.