I just moved into a new multi-family house with central heat/AC and the 3rd floor bedroom doesn't seem to warm up very well. When the thermostat is on, I don't feel hot air blowing in from the vents in that bedroom. The bathroom vent upstairs seems to blow lots of warm air and all the vents on the 1st floor apartment as well as the 2nd floor seem to work.
There are 2 thermostats per floor, with 2nd and 3rd floor being a single apartment duplex.
I looked at the setup in the basement and saw these red lights - does that mean the system is not working correctly? How can I diagnose?