R134a vs. R1234yf — First Setup & Important Usage Notes
Our A/C machines are advertised as dual-purpose, meaning they can operate with either R134a or R1234yf refrigerant.
This is true — but only before the first use.
Once refrigerant has been run through the machine, you must continue using that same refrigerant type permanently. Switching afterward can cause contamination and equipment damage.
Below is everything you need to know to set up your machine correctly and avoid costly issues.
1️⃣ Choose Your Refrigerant — One Time Only
Even after recovery or “cleaning,” a small amount of refrigerant always remains inside the machine.
Mixing R134a and R1234yf is never allowed and may result in:
Damage to the vehicle’s A/C system
Damage to the machine’s internal components
Irreversible cross-contamination
Always choose the refrigerant that matches the vehicle type you primarily service.
2️⃣ Adapter Sets Included
Each machine includes both adapter styles:
R134a: Gold body (pictured on page 2)
R1234yf: Red/blue body (pictured on page 2)
These allow you to connect to whichever refrigerant type you choose before first use.
3️⃣ AC1800 vs. AC2100 — What’s the Difference?
Both models are identical internally. The only difference is the software preset, as shown on page 2:
| Model | Default Software |
|---|---|
| AC1800 | R134a UI |
| AC2100 | R1234yf UI |
The machine does not detect the refrigerant type — it only reads:
Tank weight
Pressure values
The software simply adjusts the on-screen parameters.
4️⃣ Switching the Software (Before First Use Only)
If you must change from R134a to R1234yf, or vice-versa:
-
On the Main Menu, tap the A/C Machine icon 3 times
→ A hidden menu appears -
Select “Other”
-
Enter password:
7134 (Change to R134a)
Restart the machine to apply the new settings
No confirmation message appears — this is normal.
Need a Manual?
Access the most up-to-date manuals here:
https://autool.us/pages/manuals-resources
Need Support?
If you’re unsure which refrigerant your machine is set for or something doesn’t seem right, our Technical Support Team is ready to help.
Submit a ticket anytime:
https://katoolautoequipment.zendesk.com/hc/en-us/requests/new?ticket_form_id=33145692677140
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