My new RTH7600B when set to heat is cooling. Checked the wiring and settings to no end. What can I do?

Sounds like you might need to look at wiring again,, how about the (should be) orange that goes to the reversing valve,, this assuming you have a heatpump

What was the old tstat, how did it energize the reversing valve, and what manufacturer do you have? Does putting it in cooling mode give you any heat?

Reset setting 190 to other setting and it worked.

Reset setting 190 to other setting and it worked.

Excellent. Your RTH7600 is now energizing the O/B terminal in accordance with what your HP needs to turn on heating. It always helps to know what your equipment expects before embarking on a change of controlling equipment.