Having hard time wiring the replacment control Gas valve won't open flashing light indicat low secondary voltage . Every thing is done as per instruction

Look at these.

http://customer.honeywell.com/techlit/pdf/PackedLit/69-1955.pdf

Make sure SW1 and SW2 are in the off position.

See here

http://customer.honeywell.com/techlit/pdf/PackedLit/69-1955.pdf


Check transformer and AC line for proper input
Voltage to the control. Check with full system load
On the transformer.

Also check all your grounds in the main panel to the furnace.