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Remember to run the pump for 1 hour then close the valves and your system should hold for 1 hour then run it again for 30 minutes before you charge. Always charge by weight meaning by using the exact can volume or if you use a 30lb with a scale.
Remember to run the pump for 1 hour then close the valves and your system should hold for 1 hour then run it again for 30 minutes before you charge. Always charge by weight meaning by using the exact can volume or if you use a 30lb with a scale.
Once you've pulled the right vacuum what point would there possibly be in running it for an extra hour?
Depends how much moisture is in the system. As you pull a vacuum and the moisture boils off, you may see a drop in vacuum. So running the pump will continually draw off the gases that are boiling off.
If the system was bone dry than an hour is a waste, but if you had a leak and the system was exposed for months, an hour can't hurt.
I have seen different types of vacuum pumps on this website. The various parameters and pictures of the vacuum pumps are shown above. You can also take a look at them.
[url]https://kdlabequipment.com/pump/[/url]
You need a pretty good vacuum pump to draw down to 500 micron or less. That's virtually almost a perfect vacuum. Most of the cheapo vacuum pumps can do maybe 25-28 in-Hq but to get down to the 29.xx that you really need to boil out every bit of moisture will require a semi decent pump.
I have used a Robinair 6 CFM/2 stage to do so, but it's also a $600+ pump.
You should really do a triple-pump as well. Pull vacuum, fill with N2, pull vacuum, fill with N2 and then pull a final vacuum and begin your charging process. That should help ensure you've rid the system of moisture.
Yes, but you will need a micron gauge to properly test the vacuum. The in. Hg on your refrigerant gauges give you a good ball park, but if you are sticking to the 500 micron or less rule, you need a micron gauge. However, I think a 2.5 can vacuum pump is sufficient for a car. Heck I use 8 cfm vacuum pumps for large a/c units and it does the trick.
I repeat you don’t need an expensive vacuum pump for a car. Most of the more expensive vacuum pumps are for larger air conditioning systems. I work in the HVAC field.
Yes, but you will need a micron gauge to properly test the vacuum.
Not cheap though, especially to a hobbyist who might use it to restore the ac on one vintage car and then never use it again.
Edit: Actually, since my last post in 2014, they have become cheaper. Looks like a good option for an automotive hobbyist that might do this job once or twice.
What does the CFM mean? Is that how much air it can draw out a certain time?
You DO have a set of ac gauges and experience using them I guess? If not you are going to have issues trying to fix the car.
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