Mueller A17921 Manifold

The Mueller A17921 ReliefMaster is a heavy-duty change-over manifold engineered for high-demand industrial and commercial refrigeration applications. This HVACR manifold features a 1/2" NPTFE (National Pipe Thread Fuel Extended) inlet and 1/2" NPTFI (National Pipe Thread Fuel Injection) outlets, providing a secure, leak-proof transition for dual relief valve setups. With a design pressure (MAP) of 700 psig and a broad operating temperature range of -40°F to 300°F, the Mueller A17921 allows technicians to isolate and replace safety relief valves or rupture discs without depressurizing the entire system. Its rugged construction and dual internal seats facilitate continuous operation, minimizing downtime in critical fluid and gas distribution environments. This component is cRUus recognized and compatible with common CFC, HCFC, HFC, and HFO refrigerants and oils.

• Continuous System Operation: The change-over design enables the service and replacement of relief valves while the system remains under pressure.
• High Pressure Rating: Rated for a Maximum Abnormal Pressure (MAP) of 700 psig, suitable for high-pressure refrigeration systems.
• Robust Connection Sealing: High-precision NPTFE x NPTFI threading ensures reliable, leak-free performance under demanding industrial conditions.
• Environmental Resilience: Functional in extreme environments with a temperature tolerance ranging from -40°F to 300°F.
• Safety Compliance: Meets UL recognition standards for commercial and industrial pressure safety.

What are the specific port sizes for the Mueller A17921?
This manifold utilizes a 1/2" NPTFE inlet and two 1/2" NPTFI outlets to facilitate standard dual relief valve manifold configurations.

Can I use this manifold with new HFO refrigerants?
Yes, the A17921 is compatible with a wide range of refrigerants, including CFC, HCFC, HFC, and modern HFO blends, as well as their associated oils.

Does this manifold include internal seating for circuit isolation?
Exactly. The Mueller A17921 features dual internal seats designed to provide complete isolation of individual circuits during change-over procedures.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.