Good afternoon, I'm having issues controlling humidity throughout several operating rooms. It is a VAV system. AHU has a cooling coil only and we use VAV hot water reheat. AHU has 44 supply water temp and 53 degree return water temp. The supply water pressure is 66PSI and return pressure is 55PSI. Discharge air is 52 degrees leaving the AHU (I dropped the disharge air setting to 50 hoping to remove more moisture). AHU has a common return (shares a mechanical room with another AHU). Humidity level in the mechanical room is 48%. I climbed in to the mixed air section of AHU before filter section and humidity is 49%. I climb in to the coil section, after filters but before cooling coil and it's 53%. I climbed into the blower section of AHU, after the cooling coil and it's gaining 20 to 25% humidity. The supply air has anywhere from 70 to 75% humidity. Drain pans are clear and there is a steady flow of water coming out the drain of the AHU. Inlet guide vanes on the AHU are not working and are stuck open. Is it possible the air is moving too fast over the coil to remove all the moisture? I'm thinking of working on the vanes in order to slow the air down to test my theory.
Most of the rooms are set between 62 and 65 degrees. I noticed if I turn the thermosat up, the humidity drops. It's in direct relation to how much air is supplied from the AHU. Any thoughts or ideas would be greatly appreciated. Thanks for your time.