MSC Emergency Call: Building Automation and Air Balancing

Rising temperatures and unstable conditions in a critical area set off immediate concerns at a medical research facility in northern New Jersey. MSC was called in to diagnose the problem as soon as possible.

The conditioned space was supported by a 100% outside air unit and exhaust system and had very tight parameters for dry bulb and wet bulb conditions. MSC technicians quickly discovered that one of the four scroll compressors had failed and was shorted to ground, leaving the unit with only 75% capacity. A unit discharge static pressure reading of four inches of water column differed from the system static pressure transmitter reading at 2.2 inches, causing severe leakage at doors, plenum curb, and fittings. They also found reheat coil control valves passing hot water and adding unwanted heat to the space.

In addition to replacing the bad compressor, technicians determined that a complete rebalance and calibration of instruments was needed. The area had been constructed in five phases, and each phase of the project had been air balanced separately. No one, however, had commissioned and air balanced the area as a whole, resulting in various airflow issues. Dirty air handler fresh air intake and discharge filters were also replaced during the air balancing. Reheat control valve signals were corrected to remove unnecessary heat.

Upon completion, discharge air temperature in space conditions of ± 66° were working as designed. The system static pressure was lowered significantly and airflow readings at diffusers were adjusted to the proper design CFM. Trend logs were set up on the BAS to record system performance at all critical points to alert facility staff to problems in the future. With critical areas now working to the design intent and maintaining space conditions, the satisfied client has scheduled MSC to come back in the late fall to commission the humidification system and its controls, as well.