Can You Replace A Capacitor With A Higher Uf Hvac . Which means if the part goes bad, it’s much more complicated than opening the unit and popping a new one in. Recently i had an a/c company replace the run capacitor in my condensing unit outside. TitanHD POCD555A HVAC Oval Run Dual Capacitor. 55/5 MFD/UF 370 Volts from www.walmart.com I had an hvac company over today and the tech replaced the 5uf capacitor with a 7.5mfd on my very old inwall furnace. A capacitor is a device that stores a differential charge on opposing metal plates. The only problem there is that a capacitor rated for a higher voltage is often physically larger, everything else being equal.