Question to Chassis Temperature - Hi Limit (C)

When the threshold limit is reached, all it would do is throw an alert in the /var/log/ltm.

You can check the alert.conf for the same. You can also use the inbuild OID value, if it helps.

 less /etc/alertd/alert.conf  
alert BIGIP_SYSTEM_CHECK_E_CHASSIS_TEMP_HIGH {
        snmptrap OID=".1.3.6.1.4.1.3375.2.4.0.7";
        lcdwarn description="detected Chassis temperature too high." priority="3"
}
alert BIGIP_SYSTEM_CHECK_E_CHASSIS_FAN_BAD {
        snmptrap OID=".1.3.6.1.4.1.3375.2.4.0.8";
        lcdwarn description="detected Chassis fan failure." priority="3"
}
alert BIGIP_SYSTEM_CHECK_E_CHASSIS_POWER_BAD {
        snmptrap OID=".1.3.6.1.4.1.3375.2.4.0.9";
        lcdwarn description="detected Chassis power supply failure." priority="4"
}

There is no specific action triggered for Chasis high temperature.