I can concur with Brian's 2nd options.
I HAD a similar problem. Brand new house
(about 3300 ft2). I already bought a plug
in coupler (without repeat).
But, I still have one light switch that
seems to ignore signals. It ignores the
CM15A all the time. I finally figured out -
by walking from plug to plug with a maxi
controller - that it ignores some outlets,
but works in other outlets. I tried
turning on the 220V dryer. Plus, I already
have the coupler. No good!
Never seriously thought about noise being a
problem. But, Brian's post triggered
something in my mind, "the TV in the
bedroom".
Went to one of the plugs the DOES NOT work
with the Maxi, and confirmed that it still
does NOT trigger the light. UNPLUGGED the
TV in the bedroom - same room. And, BINGO,
the light reacts to all signals.
Gotta get a filter for that TV powerstrip.
Thanks Bri!
Rob