When I have an appliance running, I get a “hum” coming from the propane tank (2007 Class A motorhome). This occurs maybe 60% to 70% of the time. I have an “extend-a-stay” valve located between the tank and the regulator which I use for outdoor appliances and it does it when I use that also, which tells me that maybe it is not the RV regulator. Any ideas? —Dave M.
A humming noise from an RV propane regulator is not a bad thing in and of itself. It can become enhanced (the humming may get louder) after a recent fill-up if the container is slightly over-filled. But with the redundant safeguards integral to modern RV propane containers, it’s rare to end up with a grossly over-filled container.
The humming noise is caused by the rubber diaphragm inside the regulator fluctuating (as it should) to keep up with the steady demand of regulating the flow of propane to the appliances. Varying temperatures and the volume of the wet surface inside the container creates varying pressures inside.
It’s the regulator’s job to take that fluctuating pressure and smoothly reduce it to the delivery line pressure required by the appliances. The vibrating movement of the diaphragm inside the regulator body creates this harmonic dissonance of sorts that we hear as a humming noise. In most cases it is entirely normal and should not cause worry or concern. The fact you also use an extend-a-stay attachment would have no bearing on the regulator as propane would still be flowing through it whenever either container valve is opened.