R1234yf replaced R134a in new type approvals because its global warming potential is under 1, against 1,430 for R134a. Chemically it is a hydrofluoroolefin rather than a hydrofluorocarbon, and it breaks down in the atmosphere within days.
Handling
R1234yf is classed as mildly flammable (A2L). It will not ignite from a hot manifold in normal service work, but it needs a recovery machine built for A2L gases, with a spark-free vacuum pump and internal gas sensing. Service ports use a different size and thread, so cross-charging is mechanically prevented.
Parts that differ
- Compressor seals and oil: many R1234yf compressors specify PAG oil with a different additive package, and hybrid systems require POE.
- Condensers: internal heat exchangers and sub-cooling sections are common, so an R134a pattern part will not deliver the same performance.
- Driers: desiccant grade XH-9 or XH-11 is required; older XH-7 material is not compatible.
- Hoses: a lower permeation barrier construction is used.
Retrofitting
Converting an R134a vehicle to R1234yf is not approved by any manufacturer and offers no benefit to the vehicle owner. Converting the other way is illegal in most of Europe. Where a customer wants to keep an older system running, service it properly on R134a; supply remains available for existing vehicles.