Review on 🌬️ FJC 6900 1.3 CFM Air Operated Vacuum Pump: Efficient and Reliable Solution for Air Extraction by John Bailey

This is a great product if you have reasonable expectations of its performance. If you want a device that can generate 29+ inches of mercury vacuum, spend a lot more money and get a real electric pump. If you do want to fix your air conditioner from time to time, this is a great alternative to spending big bucks on a pump that you use once or twice a year. Let's say the specified spec is 4.2 cu. ft/min is probably correct. I have a compressor that outputs 5.7cfm at 90psi and have had no issues with constant air demand. I have my compressor set at 100psi static pressure with no air line connected. This gave a reading of 90psi when the unit was plugged in and running, which is what the instructions recommend. My results on a Dodge Grand Caravan with front/rear air conditioning (which contains 46 ounces of Freon) were as follows: The vacuum dropped to -20 in about 3 minutes. Up to -25 inches in another 3 minutes. 27 in another 5 minutes, and that was the maximum. So it took about 10 minutes to bring the vacuum down to about -27. It doesn't matter how long you let it run, that's the max. However, this is more than enough to boil water at room temperature, so that's all you need to get your air conditioner up and running. A lower vacuum might give you the right to brag, but it doesn't have much practical value in how well your car cools. A final note on quality is their Chinese-made, low-power base unit. I've used it twice with no problems and it doesn't look particularly fragile. I dropped the hood duct onto the concrete with no consequences. But for the price if I get half a dozen uses of this I'll be happy.