The Andrea-Mennen Welcome Center at Collin College McKinney Campus, a state-of-the-art 40,000 sq. ft. two-story facility, is designed to be the first point of contact for prospective, new, and current students seeking enrollment services, advising, admissions, and financial aid. Ensuring a welcoming and comfortable atmosphere was paramount, which meant prioritizing the HVAC system’s performance to maintain an optimal operating environment.
Challenge
During the construction phase, an urgent priority emerged: the chilled water system, crucial for temperature control, faced unexpected issues. The second-floor air handling unit (AHU) could not achieve the set supply air temperature, risking damage to over a million dollars’ worth of woodwork due to improper climate control. Our team was tasked with troubleshooting and resolving this critical issue promptly.
Investigation and Initial Findings
Our team embarked on a detailed analysis of the chilled water system, starting with the pump’s shut-off head and proceeding to verify its capacity. Surprisingly, we discovered that the discharge pressure was lower than the suction pressure, a phenomenon that led us to a thorough investigation involving various pressure measurements across the system.
The chilled water supply temperature discrepancies between the first and second floors led us to identify an air-locked condition in the piping. Initially, bleeding the air improved the situation, but the problem of inadequate cooling chilled water flow persisted, prompting us to delve deeper into the system’s performance.
Uncovering the Root Cause
Upon closer inspection of the pump and the AHU in the same mechanical room, we noted inconsistencies with the automatic flow control device and the pump’s actual waterflow, which was significantly lower than expected. These findings pointed to an issue with the pump itself.
A critical decision was made to request the mechanical contractor to disassemble the pump to inspect the pump’s suction side for potential restrictions. This led to the unexpected discovery of a pristine pump impeller and, more intriguingly, an obstruction in the discharge side made of metal, likely a manufacturing defect from the casting process. This obstruction was severely limiting the flow, allowing only 25 GPM to pass through two small openings, a far cry from the pump’s intended 150 GPM capacity.
Resolution and Success
The immediate solution involved swapping the problematic pump with one from the heating water system to restore cooling to the building, a temporary fix until a more permanent solution could be implemented. The manufacturer’s representative later honed out the metal piece, correcting the discharge opening to its full size, which resolved the flow issues and restored the system’s functionality.
This project exemplifies our team’s commitment to excellence, our ability to tackle unforeseen challenges, and our dedication to ensuring client satisfaction. Through meticulous analysis, collaboration, and innovative problem-solving, we successfully overcame a significant hurdle that threatened the comfort and safety of the Andrea-Mennen Welcome Center. This success story not only highlights our technical expertise but also our unwavering resolve to maintain the highest standards of service and performance.
Images Source: Collin College
EAB provided the troubleshooting and identification of the problem while the contractors provided the means to correct the issue. Teamwork can be defined as, the collaborative effort of a group to achieve a common goal or to complete a task in an efficient way. In the end, the success of this situation was made possible by Teamwork, which is why it is one of EAB’s Core Values. – Brian Moss, TBE
