The correct gas pressure for a 1.5-ton AC unit depends on the specific model and the manufacturer's recommendations. Typically, the low side (suction) pressure should be 60-70 psi, and the high side (discharge) pressure should be 225-250 psi. It's essential to consult your AC's user manual or a qualified technician for accurate specifications. The HVAC Alliance Expert team is available to help with any air conditioning concerns you may have.