my central air is not blowing out cool air. called called gas guy who informed me i had a leak but the leak was not up top in the unit, but underneath and said it would cost me 1500 to replace the hose, i believe he said. does any one know what hose hes talking about and can i buy it and fix it myself? he was really trying to persuade me to get this new system that doesnot use freon. but cnt aford that right now and iam very hot.