The need for a check valve before a pressure tank is not universal; it depends on specific factors, primarily legal requirements and system design considerations.
According to the provided reference, whether a pressure tank needs a check valve varies by location.
Jurisdictional Requirements
Legal regulations play a significant role in determining the necessity of a check valve in this context.
- Some legal jurisdictions require installing a check valve before the pressure tank. This is often the case to prevent water from flowing back into the well or source, ensuring the pump only needs to refill the line up to the check valve after use.
- Other jurisdictions forbid it altogether. There can be various reasons for this, potentially related to system pressure dynamics, safety considerations, or alternative methods for backflow prevention being mandated elsewhere in the system.
This means there is no single "yes" or "no" answer that applies everywhere. You must consult local building codes and regulations to determine the specific requirement in your area.
System Design Considerations: Static Friction
Beyond legal mandates, installing a check valve also has practical implications for the system's performance.
- Every extra check valve in a system adds static friction to the system. Static friction, in this context, refers to the resistance the water flow encounters when starting or maintaining movement through the valve.
Adding a check valve can potentially increase the workload on the pump or slightly reduce system pressure, especially if the check valve is not properly sized or maintained. This is a trade-off to consider against the benefits or requirements of having the valve.
In summary, the decision or requirement to install a check valve before a pressure tank is dictated by local regulations and should be weighed against its effect on system friction.
