RBM pretty much hit the nail on the head. Old stat was designed to bring
the blower relay on as soon as a call for heat was made, with the blower
on a/c speed. Meanwhile, one of the switches on the heat sequncers would
close to bring on the blower on heating speed, but it was out of the
circuit while the relay was energized. When the stat was satisfied, the
relay and power to the sequencers cut off, so the blower then dropped to
heating speed until the sequencers cut off.The sequencers bring the
strips and fan on and off with time delay (in sequence--hence the term
sequencer) Larry