Yes, in certain system designs, particularly those involving multiple boilers operating together.
Understanding Boiler Check Valves
While the necessity can vary based on the specific system design and local codes, a check valve is often a critical component in many boiler installations, especially those with more than one unit.
Why Check Valves are Needed in Multiple Boiler Systems
Based on established principles and practices in boiler operation:
- Preventing Backflow: A primary reason for installing check valves is to prevent fluid (like steam or hot water) from flowing backward into a boiler from the common header or other active boilers.
- Protecting Standby Units: As highlighted in relevant literature:
"Multiple boiler applications - A check valve must be inserted on the outlet of each boiler to prevent any steam flowing into boilers, which may be on hot stand-by..."
This ensures that steam or high-pressure fluid from operating boilers does not enter boilers that are shut down or in standby mode.
Key Scenarios Requiring Check Valves
- Multiple Boiler Installations: As directly stated in the provided reference, systems where several boilers are connected to a common manifold or header necessitate a check valve on the outlet of each boiler.
- Systems with Potential for Backpressure: Any system where downstream pressure could exceed the boiler's internal pressure when it's not firing.
Consequences of Omitting a Check Valve (in multiple systems):
- Steam or hot water from active boilers can flow back into inactive boilers.
- Potential damage to internal components of inactive boilers.
- Reduced system efficiency.
- Safety hazards.
Check Valve Placement
In multiple boiler setups, the check valve is typically installed on the outlet piping of each individual boiler, just before it connects to the common header.
| System Type | Check Valve on Boiler Outlet (Based on Reference) | Primary Reason |
|---|---|---|
| Multiple Boilers | Required (Must be inserted on each boiler) | Prevent backflow into standby/inactive units |
| Single Boiler | Varies by application/code; not explicitly covered by the provided reference | (Depends on specific system hydraulics & codes) |
In summary, while a universal "yes" for every single boiler scenario isn't strictly supported by the specific, limited reference provided, the reference definitively states that check valves are required on the outlet of each boiler in multiple boiler applications to prevent harmful backflow.
