Insteon Outlet 2473 SWH Single Control Odd Failure Mode

[jlloyd_UD]

I had one of these squirreled away for years when I decided to put it into play as a controller for a water main shutoff valve.  I connected the device to a circuit but have left it unprogrammed until later in the season when the weather is cold and I am indoorsbound.  In the meantime, I plugged a hot water recirculating pump into the "always on" side of the unit.  It has worked satisfactorily for several months until it stopped last evening.  At first, I thought the mechanical timer on the pump had failed but I thought I would check the "always on" receptacle.  Sure enough, my simple circuit testing device signals that the receptacle has "lost its ground."  I plugged the electromechanical pump into the controlled side and it worked as that receptacle must be in the "commanded on" mode or it has failed operational. I have not investigated that possibility. My intent was to plug in an I/O Linc into the controlled side to command the water main valve shut.  I will plug the pump into that side as an expedient for now.  My question is:  Why did I lose the ground circuit on the "always on" side?  I would have thought that the circuit would be completely independent of the controlled side of the receptacle even though all the wire inputs are for both sides.  Where has it failed and is it fixable?  If not fixable, what can I substitute for the single control 2473 device as I think a replacement device is no longer available?

[Brian H]

That module is rated for 480 Watts Inductive load.

It is possible the starting surge current or running current eventually caused some problems. Another thought maybe when turned off. The pump has a large voltage spike into the outlet.

No FCC database photos as it is a power line only module. So how it is constructed is not available to look and see how the ground is connected. Sounds odd as the pump should have still run without a ground but be unsafe electrically. Have you tried a test load in it. Like maybe a table lamp. As most are just a line and neutral used with no ground in the mix.