The fan can be controlled independently of the A/C or HP modes. If your thermostat is one of the newer ones it will have a FAN button. With this button, the fan can be set to Low, Medium, High or Auto. On Auto it will only come on when the A/C or heat pump is selected as the desired mode and the thermostat demands the unit on. When on Low, Medium and High the fan will be on regardless for that zone provided the zone is not set to OFF. The fan is controlled using this button for each zone independently.
You may have the fan set to one of the Low, Medium, or High modes on the zone you have the issue with (fan on all the time unless the zone mode is set to off?) and to Fan mode = Auto on the other zone (fan goes off with the A/C or heat pump).
The AUTO mode selected using the MODE button (not the fan mode) if selected will control the temp inside the AS using the A/C (to cool), heat pump (for heat when external ambient is relatively warm) and if the temp gets really low, the furnace (assuming a furnace is present on that zone).
2015 27FB International Signature "Danielle"
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