Cleaned & checked 3 gas furnaces. Inspected heat exchangers & flue venting. cleaned burners & flame sensor. Checked voltage & amp draw of motors. Test capacitors. Replaced air filters. Second floor system: Blower: 3.4A . Inducer: 1.75A . Gas pressure: 3.4 inches water column. Temperature rise: 61 . Supply: 131 . Return: 70 . Main/basement system: zone one, damper A does not close. (Stuck open). System is working with no overheating area problems. Blower: 7.2A . Inducer: 1.75A . Gas pressure: 3.4 inches water column. Temperature rise: 65 . Supply:136 . Return: 71 . Master bedroom system: excessive supply duct pressure (-.35 inches) causing whistling noise at humidifier. Customer opened supply vents to reduce pressure. Whistling noise stopped. Blower: . Inducer: . Gas pressure: 3.4 inches water column. Temperature rise: 68 . Supply: 143 . Return: 75 . Suggestions: if damper #A replacement is needed, return air Trunkline will have to be dr