R-123 PT Chart and Refrigerant Profile

Where you will find R-123

R-123 (HCFC-123) runs low-pressure centrifugal chillers, both machines built for it and older R-11 chillers converted to it. It is also used in some industrial process refrigeration. EPA lists HCFC-123 as acceptable for new and retrofit centrifugal chillers since March 18, 1994. The chiller nameplate states the refrigerant and charge.

Like R-11, it boils above room temperature at sea level (82.1°F), so an operating evaporator is in a vacuum. At 40°F saturation R-123 reads 18.2 in Hg vacuum, a little deeper than R-11 at the same temperature (15.6 in Hg). At 100°F it reads 6.1 psig. Use a gauge or transducer that resolves inches of mercury, and the pressure converter when chiller controls display psia or kPa.

Charging R-123

R-123 is a single-component refrigerant and a liquid at room temperature, so it is handled as a liquid. There is no glide, and topping off a machine after a leak is acceptable (Chemours): the composition cannot shift the way a blend’s would. Charge amount and procedure come from the chiller manufacturer’s service manual.

Because the evaporator runs below atmospheric pressure, low-side leaks draw air and moisture into the chiller rather than pushing refrigerant out. A condenser pressure that sits above the saturation pressure for the measured condensing temperature points to non-condensables; check the reading against the chart with the PT calculator. The subcooling calculator works as with any pure refrigerant, but chiller targets come from the manufacturer.

Oil and compatibility

Chemours states that the oils used with CFC-11 (mineral oil or alkylbenzene) work with R-123, so no oil change is needed when converting an R-11 machine on that basis. BITZER also lists mineral oil and alkylbenzene. Follow the chiller manufacturer for the specific grade. The refrigerant oil types guide explains the families.

Safety, handling and recovery

R-123 is B1 under ASHRAE 34. The B means higher toxicity (occupational exposure limit below 400 ppm); the 1 means no flame propagation.

Section 608: R-123 is named as an example of a low-pressure refrigerant (40 CFR 82.152; below 45 psia at 104°F, where R-123 reads 7.7 psig, 22.4 psia). That requires Type III or Universal certification. Recovery from a low-pressure appliance must reach 25 mm Hg absolute (40 CFR 82.156 Table 1), close to 29 in Hg vacuum at sea level. Venting is prohibited, sales are restricted to certified technicians, and as an ozone-depleting refrigerant, appliances with 50 lb or more are subject to the leak repair rules of 40 CFR 82.157.

Cylinders: the legacy color for R-123 was light blue-gray. Since January 1, 2020 new containers are light green-gray RAL 7044 under AHRI Guideline N-2017, with the legacy color only on the label; recovery cylinders are gray with a yellow top. See cylinder colors.

Status and replacements

HCFC-123 is a Class II controlled substance (ODP 0.02). The dates that matter:

• Since January 1, 2020, HCFC-123 may be used as a refrigerant only in equipment manufactured before January 1, 2020 (40 CFR 82.15(g)(5)). A narrow 2020 exception covered chillers under contracts signed before July 24, 2019 using HCFC-123 imported before 2020.
• Consumption allowances step down to zero in 2030 (40 CFR 82.16). After January 1, 2030, only recovered, recycled or reclaimed HCFC-123 may be used to service existing chillers (40 CFR 82.15(g)(6)).

So existing R-123 chillers can keep running past 2030, but on a shrinking pool of used refrigerant. Plan leak repair and recovery practice with that in mind.

Replacement options:

• R-1233zd(E), A1, is SNAP-acceptable in new centrifugal chillers. Its pressures are higher than R-123: at 100°F it reads 14.5 psig against 6.1 psig.
• R-514A (Opteon XP30), B1, GWP 7, is SNAP-acceptable for both retrofit and new centrifugal chillers.
• For new chillers EPA also lists R-1234ze(E), R-1336mzz(Z), R-450A and R-513A.
• HFC-245fa is listed by EPA for retrofit but is unacceptable in new chillers except under narrowed limits.

Conversions depend on the chiller manufacturer’s data. Compare GWPs on the GWP chart.

Common questions

How do you recover R-123?

With Type III (or Universal) certification and a recovery setup able to pull the machine down to 25 mm Hg absolute, the required level for low-pressure appliances under 40 CFR 82.156. Follow the chiller maker’s procedure for the sequence.

What is the difference between R-123 and R-514A?

R-123 is an HCFC with ODP 0.02 under phaseout; R-514A is a blend of HFO-1336mzz(Z) and dichloroethylene that EPA lists for retrofit and new centrifugal chillers, with ODP 0.00006 and GWP 7. Both are B1.