I read that it is important to “break the vacuum” on a vacuum pump immediately after evacuating an automotive a/c system and prior to charging to avoid damaging the pump. What exactly does that mean? I’m guessing that the vacuum is “broken” when the pump switched off and the utility hose is disconnected from the manifold set. Thank you. -Gary
The longer you leave an evacuated system sitting in a vacuum, the more risk you have of air and moisture getting pulled back into the system. You want to get the system positively pressurized as soon as possible. That is what is meant by breaking the vacuum. This is usually done by letting some of…
I’ve been pulling a vacuum on a 410 system and the compressor keeps grounding out (it’s not a burnout, I tested it for acid). The oil in the vacuum pump comes out black and has a foul odor. I can get the vacuum below 500 microns, but do not want to start the system until the oil in the vacuum pump is clear. I’m using a Yellow Jacket 11 cfm pump and Yellow Jacket oil with Yellow Jacket black hoses. Please advise.
Try changing the oil and run the pump isolated from the system for a while to see if the color and odor reappear. If it doesn’t reappear, then the problem is with the system. If it does reappear then the inside surfaces of the pump may need to be cleaned.
What are the advantages of using a evacuation manifold on a vacuum pump instead of just using a set of regular gauges?
The main advantage of the evacuation manifold is that it provides a connection point for two larger diameter hoses right at the vacuum pump. This allows you to maximize the hose diameter, minimize the hose length, and minimize the number of fittings and potential leak points. This combination will give you the fastest evacuation. A…
How Will I Know When I’ve Reached the Right Evacuation Level?
Let’s say you’re pulling a vacuum with your freshly oiled vacuum pump. The manufacturer of the unit you’re working on recommends evacuation to 1000 microns. How will you know when you’ve evacuated to that level? The pump has run for 30 minutes The sound of the vacuum pump changed to a smooth hum The gauge…
Q. What Are the Most Common Evacuation Problems?
A. The most common are: Water vapor in the system. Other contamination in the refrigeration oil and the system. Molecules detaching from the interior walls of the system. Out-gassing of rubber charging and evacuation hoses – metal hoses are available.
Q. How “Deep” Should the Vacuum Be?
A. For most refrigeration systems, ASHRAE recommends reaching a vacuum of 1000 microns or less. Many equipment manufacturers specify a deeper (lower) vacuum. To be sure that the system is not leaking the vacuum should remain under 2000 microns for several hours.
Q. Why is it important that my vacuum pump oil be clean?
A. Vacuum pumps don’t have oil filters like automobiles do; therefore, the oil must be changed frequently for the pump to perform efficiently. more (go to oil critical article on the server)