After returning from our second excursion in the Palazzo RV, we noticed a whining sound coming from the rear of the coach long after it had been shut down. I investigated and discovered that an exhaust fan was running in the compartment where the inverter resides. The inverter produces household AC power while the RV is underway, primarily to power the refrigerator.

I did an on-line search for “inverter fan running” and found a forum where my exact problem had been discussed. Many others had experienced the same thing. One forum commenter posted that there was a thermostat monitoring the air temperature in the inverter compartment and it was activating the fan at too low of a temperature, thus resulting in the continuous whine, even after a considerable cool down period.

Another commenter had solved the problem by replacing the fixed thermostat with an adjustable one. He was able to quickly replace the old thermostat with the new one (slide on tab terminals).

I ordered an adjustable snap disc fan control, S.P.S.T., close on temperature rise adjustable in 10° steps from 90° to 130°. In the (clickable) image above, you can see the new device installed with me holding the original one for comparison.

I set the thermostat to activate at 120° which should be adequate for this purpose. Our next trip takes to warm and cool places and I will be interested to see how the new device performs under varying conditions.