DUAL FUEL HEATPUMP. FOUND LOW VOLTAGE FUSE BLOWN. USED POPPER TO CHECK FOR SHORTS. FOUND TRANSFORMER HOT. RECOMMEND LARGER VA TRANSFORMER OR ISOLATION RELAY AND ADD’L TRANS. CUST DECLINED ANY FURTHER DIAGNOSTICS. EAC CELLS NEED CLEANING. SYSTEM DID RUN ON BOTH THE HEATPUMP AND GAS FURNACE MODE