Compatibility

[Mbrazel31]

 

Is my HVAC compatible?  I cant tell with the W/E wire.  The nest wouldn't power up.  Then when I put my old one back on. it wouldn't power up either. 

[johnCNA]

This looks like a fairly standard furnace & A/C system.  W/E would correlate to W1 on the Nest.  But if neither your Nest or your old thermostat won't power up, it sounds like you blew the breaker or the on-board fuse on the furnace controller board.

Check the breaker box to see if the breaker was tripped.  Still no power?  There is usually an automotive style fuse on the furnace control board.  Try checking that, too.