Does this sound right:
My heat pump split system was constantly going into defrost. Same problem for three years in a row. So this year tech comes out says pressure is good and replaces defrost board. Did not fix problem. He calls American Standard and the field service guy says replace pressure transducer. This was replaced last year and it ran all winter. My tech tells the AS field guy this and the AS field guy says I have dirty power and that the ground on the transducer relies on a earth ground. So my tech says he needs to install an 8' ground rod by the unit and run a wire between the rod and unit to protect the pressure transducer. This seems rather odd since I already have a rod at the meter box on other side of house.
I asked if the control board could be bad that it plugs into and got a no.
Any thoughts is this plausible or is smoke being blown around.