Upon arrival found downstairs system not cooling. Checked pressures and found unit extremely low on Freon. Homeowner was having siding replaced and a worker hit the line. Siding company had ac guy come and patch the leak but Freon was still leaking out of the system. With approval pumped system down and pressurized lines to perform a leak search. Checked outdoor unit/connections checked indoor coil, txv, and weld connections found no leaks. System was dropping 30psi over 15min. Thinking that they hit the line more than once. Homeowner will have siding company expose the line set and will return tomorrow. Upon arrival found it to be low on Freon. Explained to homeowner that the system could be low due to leak or no being charged properly. Homeowner wanted to perform another leak search. Pumped system down, then leak search the line set. Lines were holding pressure. Released nitrogen. Put system on a vacuum pump, 504 microns. Added 4 pounds of Freon. Pressures look good and system is