R-1336mzz(Z) PT Chart and Refrigerant Profile

Where you will find R-1336mzz(Z)

R-1336mzz(Z) is an HFO for low-pressure chillers, sold by Chemours as Opteon MZ. EPA lists it as acceptable in new centrifugal chillers, new positive displacement chillers and new industrial process air conditioning, and in new and retrofit non-mechanical heat transfer systems, all from May 23, 2016. The same molecule is also SNAP-listed as a foam blowing agent. The “(Z)” marks the cis isomer, cis-1,1,1,4,4,4-hexafluoro-2-butene; the trans isomer R-1336mzz(E) is a separate refrigerant, and this chart does not apply to it, so check the full designation on the nameplate.

BITZER lists it as a substitute for R-123 and R-245fa. It is also the main component (74.7%) of R-514A, the R-123 retrofit blend.

It is the lowest-pressure of the current chiller refrigerants. R-1336mzz(Z) boils at 92.2°F at sea level. At 40°F saturation it reads 20.9 in Hg vacuum (R-123: 18.2 in Hg), and at 100°F only 2.5 psig (R-123: 6.1 psig). A condenser at moderate temperatures is barely above atmospheric pressure, and below about 92°F the whole machine is in a vacuum. Use a gauge or transducer that resolves inches of mercury, and the pressure converter for psia or kPa readouts.

Charging R-1336mzz(Z)

R-1336mzz(Z) is a single-component refrigerant and a liquid at room temperature, so it is handled as a liquid. There is no glide: one PT column serves the evaporator and condenser, and leaks or top-offs do not shift composition. No manufacturer charging guidance was retrieved; charge weight and procedure come from the chiller manufacturer’s service manual.

With so much of the system below atmospheric pressure, leaks let air and moisture in rather than letting refrigerant out. A condenser pressure above the saturation pressure for the measured condensing temperature points to non-condensables; check with the PT calculator. Refrigerant-side subcooling checks work as with any pure refrigerant, with targets from the manufacturer.

Oil and compatibility

BITZER’s table lists “POE special” for R-1336mzz(Z). What makes it special (grade or additive package) was not confirmed, so use only the lubricant the chiller manufacturer specifies. EPA’s chiller listing is for new equipment only, so there is no listed path for converting an R-123 or R-245fa machine to neat R-1336mzz(Z).

Safety, handling and recovery

R-1336mzz(Z) is A1 under ASHRAE 34 (UNEP/ASHRAE factsheet, BITZER, EPA SNAP tables): lower toxicity, no flame propagation. That is a step down in toxicity class from R-123 and R-245fa, which are both B1.

Section 608: at 104°F R-1336mzz(Z) saturates at 3.9 psig (18.6 psia), under the 45 psia limit, so it is a low-pressure refrigerant (40 CFR 82.152). Work on these chillers needs Type III or Universal 608 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. As a non-exempt substitute it may not be vented, and since January 1, 2018 sales are restricted to certified technicians (40 CFR 82.154(c)).

Cylinders: AHRI Guideline N-2017 Table 1 assigns no legacy color to R-1336mzz(Z). New containers are light green-gray RAL 7044; recovery cylinders are gray with a yellow top. See cylinder colors.

Status and replacements

HFO-1336mzz(Z) is not a controlled ozone-depleting substance under 40 CFR 82 and not an AIM Act regulated HFC. It needs no allowances, and the Technology Transitions GWP limits do not apply to the neat fluid.

GWP depends on the basis. IPCC AR4 has no value; AR5 gives 2 and AR6 2.08; EPA assigns 2 in 40 CFR 84.64; EPA’s SNAP chiller page lists 9. All are very low. EPA’s 2016 rule notes that it is a VOC and is not exempt from the VOC definition.

Where it fits: for a new low-pressure chiller, R-1336mzz(Z) sits alongside R-1233zd(E) and R-514A on EPA’s list. For an existing R-123 machine, R-514A is the option EPA lists for retrofit.

Common questions

What is the difference between R-1336mzz(Z) and R-1233zd(E)?

Both are A1, low-GWP, low-pressure chiller refrigerants listed for new equipment. R-1336mzz(Z) runs at lower pressures (20.9 in Hg vacuum at 40°F, 2.5 psig at 100°F) than R-1233zd(E) (12.6 in Hg vacuum, 14.5 psig), so a chiller is designed for one or the other.

Is R-1336mzz(Z) the same as R-1336mzz(E)?

No. They are the cis (Z) and trans (E) isomers of the same formula, with separate ASHRAE designations and separate property data. BITZER lists both as R-245fa substitutes; this page covers only the Z isomer.