Servicing 1234yf Refrigerant

Let me start this off with saying that a 1234yf system is VERY similar to an R-134a system. If you are familiar with 134a repairs then you should be just fine with YF repairs as well. That being said there are a few points that I want to make:

  • Just like before in order to legally work on an HFO-1234YF unit you will need to be section 609 certified with the Environmental Protection Agency. If you are working at a shop then you are most likely already certified but if you are not then contact your service manager and see what steps need to be taken to get you certified. The certification is no different between R-134a and R-1234YF.
  • While a new certification is not necessary there is additional training available through SAE Spec J2845. This training will go over specific requirements and techniques when servicing either 1234yf or R-744 mobile air conditioning systems. The easiest way to acquire this training is to retake your 609 certification exam through MACS Worldwide. They have updated their test to include YF material.
  • The recovery and recycling procedures on 1234yf machines are basically identical to R-134a machines. The only differences that you will notice are:
    • When beginning to charge your system the recovery machine will do a vacuum hold test that will go for around two minutes. If the vacuum holds then we move onto the next step. If it doesn’t hold then check for leaks in your system.
    • Once we have passed the vacuum test the recovery unit will deliver a fifteen percent charge to the system. This is known as a ‘precharge,’ of the system.
    • While this is going on the tech will be prompted to start the blower motor on low, grab his leak detector, and then check the front evaporator inside the car for any leaks.
    • After giving it some time to check for leaks go back to your recovery unit and alert it if you found a leak or not. If your vehicle has a dual system then you will also need to check your rear evaporator for leaks as well.
    • If the leak detector did not trigger any leaks with the fifteen percent charge in the system then the recovery machine will go ahead and put the rest of the refrigerant back into the system.
    • After the system has been fully charged, disconnect your lines, and reseal the valves just like your normally would.
    • Some of you may be groaning at the extra steps when compared to R-134a. Well, with all things, there is a reason why these are performed. The fifteen percent precharge and leak detection step is key to catching a leak on your vehicle before it has been fully charged. If we catch the leak early while the charge is still low we can save loss of refrigerant, save your shop some cash on that refrigerant, save the customer money, and also prevent further damage to the environment. It’s a win win for all involved.


Besides that folks 134a and 1234yf are basically the same. Yes, it’s a different refrigerant and yes you will need new tools which is always a hassle but once you get the proper equipment the actual diagnosis, repair, and replace are very close to what you do today with 134a.

There are two more points I want to make before closing this article. The first is that there is a great resource that Honeywell has provided that will show you training videos, service videos, and any and all other questions that you would have on 1234yf. Their are two websites that I’m going to recommend here.

The first is called and goes over all frequently asked questions, fact sheets, and anything else you’d like to know about the refrigerant. The second website is This website has in-depth training videos on 1234yf and will also provide a short quiz and certificate once you have completed the course. I took these the other day and they were very helpful.

Alright, the last thing I’m going to mention here is here at RefrigerantHQ we took the time to create a recommended tool listing to service your 1234yf vehicles. This guide will give you everything from a leak detector to a recovery unit.