[Richard]

No two Newells are alike. My comments are based upon what I see in the pictures.

Let’s start with the very necessary understanding that the 120V pump is powered by parallel control mechanisms. Normally, power flows through the SquareD well pump switch as shown in your picture.

However, HWH supplies a relay with the leveling system that supplies power to the 120V pump whenever the coach is in level and calls for air to raise a corner or side. That relay goes AROUND the well pump switch and provides as much pressure as the pump is capable of. For a new Thomas compressor that can exceed 150 psi. The coach systems are NOT rated for 150 psi. For examples the safety blowoffs on the ping tanks are usually 135 psi. So, some sort of mechanism must be added to the 120v air supply to prevent the compressor from exploding an air bag.

Someone has added a safety pop off valve to one of the ports on the well pump switch. Those can fail. I suspect that is what is popping. Before I would condemn the pump, I would replace the pop off valve or simply put a pipe plug in that port.

The regulator looking thing in R1 bay is probably the original device intended to limit the pressure on the system.