Whoops, found the thing and realized that if the HMI program is locked down you will probably have an issue :
ComfortPanelSmartServerSetup.pdf (609.1 KB)
It’s so simple though there’s a small chance you could convince the mfg to remote in and set it up. It’s also not entirely uncommon for the PLC program to be locked but the HMI not.
Is there no external stop/start command? Is there a non-latching fault you can simulate to put the unit on hold? In the past I’ve used a wifi enabled thermostat as a remote to trigger a dry contact (like resetting a building chiller or closing a contractor for a cooling tower fan). Janky AF but it works