I originally posted this over on the Smarthome forum. They suggested that there may be some pro's here that could help. PLEASE, HELP!
*********************
When we bought this house over 7 years ago there was a funny looking light switch for an outside light over the garage door. Since the spouse is the tinkerer it was discovered that it was an X10 on/off light control. Since we were looking for a way to turn on/off the hot H2O circulating pump, we bought a master control that works directly over the house power lines (not RF) and an appliance control for it. These are the only two X10 devices that we have. A few years later we bought another master control which is different but still only controls 16 devices in the A group directly over the house power lines.
I am by no means a pro at this, but I have an issue with the light control device. The existing wall switch looks very much like the X10 WS467 In-Wall X10 Light Switch but it has only one push button and not the lower, smaller button (what's that for?). In the last few months the outside light is randomly turning on by itself. It responds to an off signal from the master control. Since it does this even very late at night, I do not suspect that a neighbor has X10 devices that are interfering with my system. I have tried to correlate these events with the newish furnace running but I cannot do that perfectly.
My meager knowledge of X10 indicates that the control signals for X10 are too complex and it seems unlikely that any noise, including the furnace/AC, could cause the light control to turn on. It seems to me that it is much more likely that the light control wall switch is failing or even possibly that one of the two master controllers is sending turn on signals by itself (one master control has a door over the send signal selection buttons which greatly affects whether it works properly or not if it is not very carefully closed). I would greatly appreciate more knowledgeable opinions on this situation.
Thank you.