Originally Posted by lhaviland
We changed the thermostat last night b/c we'd changed the run cap the day before and there was no change. Someone suggested that it may be the thermostat, so we purchased a universal thermostat.
Sorry to be blunt, but that's a crappy way to troubleshoot!!
Randomly replacing new parts in hope that you get lucky and find the culprit is rediculous. Now you just introduced 3 new variables which will impede your ability to narrow down the problem.
(ex: not only do you have a malfunctioning system, but now you may have a malfunctioning system with a suspect thermostat.)
Although this forum is DIY, this is a good time to seek out help from the pros. A HP can be controlled via jumper wires at the control board which will simulate the operation of the thermostat. That's a better way of determining if the problem is related to the thermostats ability to control the system.