The choice of using Schrader cores over king valves in HVAC equipment is not necessarily due to one being superior to the other. Both types of valves have their advantages and disadvantages, and their selection depends on various factors, including cost, ease of use, and industry standards.
King valves are generally considered more robust and reliable. They are typically large, quarter-turn valves that are easy to operate and provide a full opening for unrestricted refrigerant flow. They are commonly used in HVAC systems for larger lines, such as liquid and suction lines, as well as in refrigerant charging and recovery processes.
On the other hand, Schrader cores are small, spring-loaded valves commonly used in refrigeration and air conditioning systems for access points, such as service ports. They resemble the Schrader valves found in car tires and are widely used for quick and convenient connections during service and maintenance tasks. Schrader cores allow technicians to easily attach hoses and gauges to check pressures, add or remove refrigerant, and perform other diagnostic procedures.
The reason you might have experienced more trouble with Schrader cores could be attributed to a few factors:
Frequent Service Access: Schrader cores are designed for frequent use, and they are meant to be accessed during service and maintenance activities. The more they are used, the higher the chances of wear and potential leaks. On the other hand, king valves are not accessed as often, which could contribute to their perceived reliability.
Size Differences: Schrader cores are small and delicate compared to king valves. If they are accidentally damaged or improperly tightened during service, they can develop leaks more easily.
Lack of Proper Maintenance: If Schrader cores are not replaced or serviced regularly, they can become prone to leaks and issues. Proper maintenance of Schrader cores is essential for their reliable operation.
Variability in Quality: The quality of Schrader cores can vary between manufacturers and brands. Some lower-quality Schrader cores may be more prone to issues compared to others.
Survivorship Bias: As you mentioned, it's possible that survivorship bias plays a role in your perception. If you've had more exposure to Schrader cores due to their frequent use during service tasks, you might also encounter more problems with them.
Overall, both king valves and Schrader cores serve different purposes in HVAC systems. While Schrader cores offer convenience and ease of access, king valves provide robust and reliable control over refrigerant flow. Proper maintenance, handling, and adherence to industry best practices can ensure the optimal performance of both types of valves. If you continue to experience difficulties, it's always best to consult a professional HVAC technician for accurate diagnosis and resolution of any issues.