AboutCraig HVAC Expert Expertise I have been in the HVAC field for the past 12+ years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.
Experience I have work in the HVAC trade for the past sixteen years. I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.
Education/Credentials 5 years union trade school, VFD training classes, Liebert factory training, some York and Trane factory training.
Question hi. i'm confussed on using vacuum pumps. wondering if you could help. does all the refrigerent have to be out of the system to pull a vacuum. and if so what do you do when your installing a new unit and it already comes with freon in it,do you have to remove the gas to vacuum the line set. also do you leave the service valves open or closed when using the vacuum.the reason i ask is i have 2 units at the house, 1 is used and i would like to vacuum it out, and the other is brand new ready to be put in but not sure what steps to take to pull a vacumm. thankyou for your time. Kevin
Answer The service ports on the service valves are opened to the line set. Get the vac on the line set, then open the service valves on the cond. unit. The law requires that the line set be evactuted. You can pump down the unit, close the service valves and finish removing the rest of the gas with a recovery machine.
