Tracking down a vibration sound

[TeamRAB]

So, the past few weeks, we have been trying to track down a noise that sounds like a dull vibration. It sounds like when you get a text message, but your phone is under the pillow, and lasts about half a second.

We believe it is coming from the water system area, but even with the water heater off, we still hear it.

We have been camping in full service parks, the tanks are closed, water pressure always regulated to ~40psi.

The trailer is a 2018 White Hawk 29RE.

Any thoughts?

[RogerR]

My water pump does not deliver a dull sound, it will wake you up even after I insulated it. Pull the panel and see if it is the noise source. It could be that water is running backwards through it if the valve is bad.
On mine its not the pump but the hoses going through thin cabinet walls.

Second thought is the converter fan blade is rubbing or has a bad berring.