As of last night, when I turn the a / c or fan thermestat, a loud noise comes from the floor in the basement, where the furnace is. The A / C unit outside seems to be working but nothing is blowing out of the vents. What can be the problem. From what I can say … Since you have a central air system, air ducts of metal, which expand and contract with changes in temperature are used. When the A / C starts forcing cold air through the vents initially collides with warm air, and ventilation ducts are expanding and contracting and appearing for a few moments until its temperature is adjusted to the cooler air. No problem. . It is normal. Papaya
Recharging a central air refrigerant involves connecting the gauges and taking accurate temperature reads, but also requires a certification from the EPA. Find ou. . .