No heat in 2 zones

Jackgiz

I'm at at daughter's house for Xmas and she tells me that some of the rooms are cold.  Checking in the basement I found 4 zones controlled by Honeywell V8043 valves.  2 of the loops are hot and 2 are cold. 

I pulled the cover off one of the cold zones and disconnected the Tstat wire.  The mechanism in the power head moved.  I took the 2 screws out of the power head and removed it from the valve body.  The little stem coming out of the valve body turns freely, very freely.  Could something be broken inside the valve?  I moved the stem to the end stop in both directions and the pipe still stayed cold.  I checked every valve on the loop that I could find and they all appear to be open.  This loop goes to a second floor bedroom.

Could the valve itself be stuck closed but the stem still turn?  Like I said the stem moves very freely almost like it's not connected to anything.

Could there be an air bubble in the system?  How much pressure does the circulator pump put out?  Can it pump a column of water up to the second floor?