I installed a CESO 110057-02 board on a Bryant 373LAV product and the trouble code reads fast flashing for reversed polarity or twinning problem.

Reversing the polarity had no effect. There is no twin. 24 VAC transformer replaced.

Blower only comes on.

Any help appreciated,

Vern

Try reversing the 24 volt wires from the transformer to the board. Also check to be sure the bare or green wire from the electrical panel in your home is grounded to the furnace and that the white is on the neutral bar and the black is on the circuit breaker in your electric panel.

Tried reversing the 24 V leads to no avail. All I can think is a bad board out of the box.
Test cycle will start, but there is no reaction in any of the 24 V circuitry. Even with both safety loops jumped out, nothing happens.

If you have power to the board something should be happening. If there is a fuse in the unit is it OK. Jump to the G terminal does the fan start running?