Great illustration of failure to rid the pumps life blood of moisture. Thx very much 👍 If this doesn’t make the point about the importance of pump maintenance, I am not sure what would.
Thankfully for great illustration Mr.Ty. If used one stage vacuum pump will do the same job as 2 stage? What about the cfm as the number is higher the vacuum will be deeper is that correct? (Of course with using core removal and large hoses). Makita has a vacuum pump 1 stage and I think 2 cfm cordless do you think that pump could do the job? Thank you.🥀
Lower CFM should result in a deeper vacuum (a lower ultimate pressure), time to reach ultimate vacuum will be longer though. A single stage pump could theoretically reach a deeper vacuum than a 2-stage pump due to tighter tolerances, less internal leakage, but of course will take longer. I use a single stage pump with a small motor running for 12 hours or more if the system is old and has had contamination issues, virtual leaks (outgassing) can require quite some time (beyond 12 hours) to resolve in this case. If the system is clean and dry, a 2-stage pump will pull a nice vacuum in a short time, the larger the system, the 2-stage pump is faster. I think the Makita 1-stage 2CFM pump would work fantastic for evacuating a typical residential system.
No sir, keep the oil changed and it will last. You your career. However if it's been abused, or if you do a blank off test and it's not pulling down then yes.
i have question the vanes of the secend stage (small stage ) but the first stage is fine and i can't find the vanes in markert the question is can i use in normaly with only the main big stage
Doesn't seem like removing 14.7 psi of atmosphere would be a difficult task requiring careful preparation and specialized equipment, does it? After-all, it's only 14.7 psi... Yet, we can never evacuate all of it! ;)
Exactly! its so cool! only 14.7 but so evasive! The true missing piece of the puzzle is not only pressure but also lack of molecules. trying to get those last molecules out is the real challenge.
@@love2hvac Yes, the definition of vacuum is absence of molecules. These molecules of contamination (non-condensables) must not be allowed to interfere in the process of evaporation and compression of refrigerant. In order to remove these molecules of contamination, they must find their way into the vacuum pump. At 1st during the evacuation process, the molecules still remaining in the refrigerant tubing bump into each other, pushing the others into the vacuum pump but as pressure decreases, there are fewer molecules to push other molecules towards/into the vacuum pump, thus rate of pressure decay slows, and the mean free path of the molecules becomes longer.
