Aciq new install: code fhcc

I just recently installed a, Aciq-30-ahd and Aciq-30-ehpd. Have a tlo4-1 thermostat, 2 wire shielded in and out grounded at outside unit. It hasn't even run. Im getting FHCC for gas leak detector. Im at a loss. It's registered for warranty, but the warranty process is a lot. My technician has never installed one before. We are both stumped. We have checked wiring and hard resets. Can it just be a bad sensor(doa) on a brand new system? Im running window units now,in Texas. Any ideas or suggestions? Thanks