I have a RUUD Model UPFB-024JAS Outdoor Heat Pump, and the reversing valve selenoid (part number 61-17286-04) makes a buzzing sound when engaged in heat mode. I have replaced the selenoid with an original part, and verified that it is mounted correctly on the reversing valve shaft. I have observed that depending on how tight (or loose) I make the retaining nut on the selenoid, I can reduce or increase the buzz noise; however, I dare not tighten too tight lest I damage the reversing valve body.
Any suggestions on how I can eliminate the buzzing noise? I tried a washer on either end of the selenoid, but to no avail. The clearance between the reversing valve shaft and the selenoid itself is too close to wedge a piece of paper or some tape between the two surfaces.