Came back from a trip out of town and noticed the spot on my PDA that used to say solar now says "heat pump"?
Systems detects the solar sensor, but the "Solar" option is no longer on the menu.
The system still turns the solar 3 way valve open and closed but it no longer detects heat differential and is always open or always closed at least until it hits the temp set.
Any ideas? Maybe the battery in the main unit which reads low according to the pda.