We develop Zigbee thermostat devices for heating only. When we connect a thermostat to our Echo Plus, we specify that it only support the heating in the protocole. When we change the temperature with Amazon Alexa app, the temperature change successfully but Alexa react as if there was an error. On the Amazon Alexa app, a small popup appears saying 'Device is unresponsive'. This is a major issue since we want to certify our product with wwa.
Our Echo Plus ask for those parameters to which we respond unsupported
attribute: OccupiedHeatingSetpoint (0x0011)
cluster: Thermostat (0x0201)
profile: Home Automation (0x0104)
Our guess is that echo Plus act as if our thermostat were HVAC devices when they only support heating.