Fan not starting when AC start

[Doug10]

I just purchased a new Nest Learning Thermostat Gen 3 to replace same model thermostat that the battery died on. This thermostat runs a heat pump. I snapped it into the existing wire base and I set it up on my Wifi and my iphone. I set the temp low to start the AC. The outdoor unit and indoor unit started but the fan blower did not start. I walked to the indoor air handler and the lines were very cold so I "manually" turned the fan on with the Nest thermostat.  I have walked through this same process three time.  It is blowing cool air but I need it to start the fan when the AC comes on. I did not try it in heat mode.

[Patrick_Caezza]

@Doug10 

You should use the new base that came with the new thermostat. In theory, it should work with the old base, but there have been revisions and upgrades through the years that might make it not fully compatible.

[Doug10]

Thanks for reply, I have good news and for future reference. After checking nearly every setting I discovered the Nest was set to Radiant under the heat pump settings rather than forced air. Bingo problem solved.

[Doug10]

I have good news and for future reference. After checking nearly every setting I discovered the Nest was set to Radiant under the heat pump settings rather than forced air. Bingo problem solved.