When on the cool setting we are unable to get the temperature to go below 70 - is there a setting that needs to be unlocked?

Trying to get house cooler then 70? In summer that is almost impossible unless you have a super insulated, fully shaded house. Heat load on house cannot be offset by BTU from AC.

Noboy I know of tries to cool their house below 70. Most only cool to between 72 & 78, with the vast majority between 74 & 76.

Agreed it will probably not go below 70 on a hot day. That being said if you can't get the setting below 70 then it is lock out to that temp and must got to the installer setup to change set point