Check your supply, verify that you have 240 volts between the two hot wires.

Thanks for the note Dan. �I will verify. �Is there any plausible
reason that my supply coming off the double pole breaker would not be
180 degrees out of phase?

result, double pole breakers have 240 volts between their hot wires. �I would
be very surprised if there was something different at the breaker. �However
there may be a problem between the breaker and your switch. �For instance, the
two hot wires from your switch may not connect to the double pole breaker like
you think. �A couple of measurements with a voltmeter should give you more
information.-

Dan & Jeff

Maybe the "double breaaker" is in fact one of theose breaker bodies
that has two breakers in one housing so each breaker is on he same
leg!!

Bob AZ