How do I top up my own air con refrigerant?
If you want to have a go at topping up your car's air con refrigerant by yourself, it’s important to follow the instructions carefully as releasing the gases can be harmful to the environment.
Below we’ve provided a handy guide to topping up using the A/C Pro R-134a Recharge Gas and the A/C Pro Air Con Digital Trigger and Gauge.
Remember, you need to get the right type of gas for your car, as gas types differ from vehicle to vehicle depending on age and model. If you’re not sure which gas you need, check out our Vehicle Registration Number tool. You can enter your registration number and it’ll display compatible gases. Alternatively, head to your local Halfords store and one of our expert colleagues will guide you. Check out our full range of air-con gas refrigerants here.
Please note: before starting, make sure you’re wearing safety gloves and protective glasses.
Step 1
To start, you need to open up the bonnet and find the low-side pressure service port. This is located on the widest pipe connecting to the air-con (there are two), usually between the AC compressor and evaporator. The hose provided with AC Pro’s products is designed to fit this port, so you’ll know when you’ve identified it.
Once identified, remove the port’s cap and start your engine and air conditioning. The air con needs to be at full capacity with maximum cooling and recirculation activated. Keep it going for three minutes and ensure the engine’s compressor is running and the clutch is engaging.
After this, connect the A/C Pro Air Con Digital Trigger Gauge to the port using the quick-connect hose.
Step 2
With the car still running, you can use the A/C Pro Air Con Digital Trigger Gauge to perform a diagnostic check. Easy to use, this device provides a PSI reading along with required actions based on this. There’s also a progress indicator along the screen which displays charging progress.
With the device connected to the port, check the reading. You will see one of four possible readings:
- Caution, abnormal leak – see instructions
- Pressure is low, squeeze the trigger to fill
- Pressure is good, fill until vent air is cold – do not overfill
- Caution, pressure exceeding recommended levels – see instructions
Use this reading to guide you on your next steps. If you’re unsure, you can also refer to the label on the canister.
If the pressure gauge comes up with a ‘warning’, there is a problem with the system and you should not attempt to top up the refrigerant. Instead, you should get it checked out by trained technicians, and the easiest way is with our Free Air Con Check.
Step 3
If the gauge says, ‘Pressure is low’, the refrigerant needs topping up.
Disconnect the gauge from the port. Take the A/C Pro R-134a Recharge Gas and give it a thorough shake before attaching it to the gauge by screwing it on.
With the engine still running, reattach the gauge to the port. You can then start recharging the refrigerant. Doing so is easy. Just squeeze the trigger on the canister while shaking the can. Make sure you keep the can upright throughout the process.
Stop every so often to check the pressure level using the gauge. The gauge will indicate, ‘Filling, release trigger in 15 sec. to read pressure’. Keep filling and following this release instruction until the filled message appears. It’s important to closely follow these messages so you don’t overcharge it.
When the needle reaches the green zone and the car blows cold air, you’re done. It’s that simple!