After removing air from the lines and replacing the thermostat we continue to have problems getting the temperature in the house to go above 60 degrees. We have an upstairs and downstairs thermostat. The room upstairs containing the thermostat is toasty warm registering at 70 degrees just as it is set on thermostat. However the downstairs thermostat we have set all the way up to try to get some heat but it continues to stay at 60 or below. We have replaced the thermostat purged the lines to release the air and still the temp will not budge. This is a hot water baseboard unit. What else can we try in order to get more heat? There are no heat sources around the thermostat to interfer with performance. Any suggestions?