R407C Refrigerant: Properties, Pressure Chart, Uses & R22 Replacement Guide

R407C refrigerant is a common choice in cooling systems that replaced older gases like R22. It is a mix of three refrigerants that work together to deliver steady cooling. Moreover, you will find it in many AC units and heat pumps. It is still widely used in existing systems.

This guide explains what R407C is, how it works, where it is used, how to read its pressure chart, and what to know before replacing it.

Table of Contents

What Is R407C Refrigerant?

R407C is not a single gas. Instead, it is a mix of three refrigerants: R32, R125, and R134a. These components work together to provide stable cooling performance. Because of this blend, R407C behaves differently from pure refrigerants.

For example, it has something called temperature glide. This means it does not evaporate or condense at one fixed temperature. Instead, the temperature changes slightly during the phase change. As a result, technicians need to handle charging and servicing more carefully.

Moreover, R407C is highly effective for medium-to-high temperature applications, such as walk-in coolers, vegetable cold storage, and chillers. It is commonly used in residential AC units, commercial HVAC systems, and heat pumps. It is especially popular in systems that were originally designed for R22 and later converted.

However, it is not recommended for low-temperature walk-in freezers (below -15°C), where its capacity drops significantly and high discharge temperatures can compromise compressor reliability.

Overall, R407C offers zero ozone depletion potential, which makes it safer for the environment than older refrigerants. However, it still has a moderate global warming impact, so newer alternatives are slowly replacing it.

Key Properties of R407C Refrigerant

R407C has a set of properties that directly affect how it performs in cooling systems.

The following are the most important physical, environmental, and operational properties:

Property	Value / Description
Refrigerant Type	HFC (Hydrofluorocarbon blend)
Composition	R32 (23%) / R125 (25%) / R134a (52%)
Molecular Weight	~86.2 g/mol
Boiling Point	-43.6°C
Critical Temperature	~86.7°C
Critical Pressure	~4.63 MPa
Ozone Depletion Potential (ODP)	0
Global Warming Potential (GWP)	1774 (IPCCAR4) / 1624 (IPCCAR5)
Temperature Glide	~5°C to 7°C
Pressure Level	Medium (similar to R22)
Oil Compatibility	POE (Polyolester oil)
ASHRAE Designation	A1 (Non-flammable)
Toxicity Class	Low toxicity
Latent Heat Capacity	Moderate
Density (Liquid)	~1.1–1.2 g/cm³
Fractionation Risk	Yes (due to blend)
Charging Method	Liquid phase only
Operating Temperature Range	Wide range for AC and heat pumps

Advantages of R407C Refrigerant

R407C offers several practical benefits:

Zero Ozone Depletion Potential: R407C contains zero ODP and is considered an environmentally friendly option. Additionally, it does not harm the ozone layer.
Suitable Replacement for R22: It is widely used as a retrofit refrigerant for R22 systems. Most conversions require lubricant replacement, system evacuation, and performance adjustments.
Widely Available: It is easy to maintain the R407C because of its availability. You can easily find it in the global market.
Good Performance in Existing Systems: You can expect reliable cooling performance in systems designed or retrofitted for it. Moreover, it maintains stable operation when installation is done carefully.

Disadvantages of R407C Refrigerant

Despite its advantages, R407C also has some technical and environmental limitations that should not be ignored.

Temperature Glide Challenges: R407C has a temperature glide of around 5–7°C. This means it does not evaporate and condense at a single temperature, which can make system tuning and efficiency management more complex.
Requires POE Oil: It needs POE (Polyolester) oil, which absorbs moisture easily. Therefore, strict handling and sealing are required during installation and maintenance.
Fractionation Risk During Leaks: Usually, when leaks appear, the mixture of gases is. And this separation can cause an imbalance in system performance over time.
Moderate Global Warming Potential: Although it has no ozone depletion effect, R407C still has a moderate GWP (~1774). Because of this, newer low-GWP refrigerants are gradually replacing it in modern systems.

How to Read R407C Refrigerant Pressure Chart

Reading pressure charts helps technicians to identify the refrigerant behavior at different temperatures. Basically, they show the relationship between temperature and pressure inside the system.

Because of this, pressure charts are used for:

Charging and servicing systems correctly
Detecting performance issues
Ensuring efficient cooling operation
Avoiding overcharging or undercharging

How to Read Pressure vs Temperature Values

R407C does not behave like a single refrigerant. Therefore, relying on just one pressure value is not the case here.

Instead, you need to understand:

Evaporator side (low pressure): helps check cooling performance
Condenser side (high pressure): shows heat rejection efficiency

As the temperature changes, the pressure also changes in a predictable way. So, technicians match the measured pressure with the chart value to confirm if the system is working normally.

Bubble Point vs Dew Point (Important for Blends)

R407C is a zeotropic blend, which means it has a temperature glide. Because of this, it has two different reference points instead of one.

Dew Point:
This is the temperature where the liquid starts to evaporate. It is used for the evaporator side (low pressure).
Bubble Point:
This is the temperature where vapor starts to condense. It is used for the condenser side (high pressure).

Understanding this difference is very important. Otherwise, incorrect readings can lead to poor cooling performance or wrong refrigerant charging.

Here is a R407C Pressure Chart (Temperature in °F) for easier use in HVAC work:

Temp (°F)	Dew Point (Liquid)	Bubble Point (Vapor)
14°F	44.0 PSIG	31.7 PSIG
21°F	52.5 PSIG	39
32°F	68.6 PSIG	52.0 PSIG
41°F	83.3 PSIG	64.3 PSIG
50°F	100.0 PSIG	78.4 PSIG
59°F	115.8 PSIG	94.9 PSIG
68°F	135.8 PSIG	113 PSIG
86°F	182.4 PSIG	155.9 PSIG
95°F	209.4 PSIG	181 PSIG
104°F	239.0 PSIG	208.9 PSIG
113°F	271.4 PSIG	239.7 PSIG
122°F	306.9 PSIG	273.8 PSIG
132°F	349.7 PSIG	315.4 PSIG
141°F	391.8 PSIG	356.9 PSIG
150°F	437.5 PSIG	402.5 PSIG

R407C vs R22 vs R410A vs R32

Refrigerant	ODP	GWP
R407C	0	1774
R22	0.055	1810
R410A	0	2088
R32	0	675

Final Words

R407C refrigerant remains an important part of modern HVAC systems. It is a blended refrigerant designed to deliver stable cooling performance while reducing environmental harm.

In addition, the pressure chart is essential for correct system performance. Since R407C is a zeotropic blend, technicians must always consider both bubble point and dew point. This ensures accurate charging, better efficiency, and longer system life.

FAQs

What is R407C refrigerant used for?

R407C is mainly used in air conditioning systems and heat pumps. It is common in residential, commercial, and retrofitted HVAC systems where stable cooling performance is needed.

Can R407C replace R22 directly?

No, R407C cannot replace R22 directly. The system needs modifications, such as changing to POE oil and proper flushing. It is used as a retrofit option, not a direct drop-in replacement.

Is R407C environmentally safe?

R407C has zero ozone depletion potential, so it does not harm the ozone layer. However, it has a moderate global warming potential, so newer low-GWP refrigerants are now preferred.