Spirax-Sarco 55440 Disc

The Spirax-Sarco 55440 is a precision-engineered thermodynamic steam trap disc designed for use in 3/4" TD52, TDC, TD52H, and UTD52SLH series traps. Constructed from hardened 420 stainless steel, this disc serves as the primary moving component, utilizing the kinetic energy of flash steam to regulate the discharge of condensate. In high-pressure steam systems, maintaining a tight seal is critical to preventing live steam loss; the 55440 disc is ground and lapped to exacting tolerances to ensure a positive shut-off and long-term condensate removal efficiency.

For technicians servicing steam main drainage or process equipment, replacing a pitted or worn disc restores the trap to its original operating specifications without requiring a full body replacement. The thermodynamic disc trap technology permits operation in any position, though horizontal installation is preferred to minimize friction on the TD52 replacement disc. This part is specifically rated for high-temperature and high-pressure service up to 600 psig and 800°F, making it a rugged choice for HVACR steam systems subjected to water hammer or superheat.

Key Benefits

• Precision Seal: Lapped 420 stainless steel construction prevents steam leakage and reduces rapid cycling.
• Broad Compatibility: Engineered for 3/4" Spirax-Sarco TD52, TD52H, TDC, and UTD52SLH thermodynamic traps.
• Operational Feedback: Features the characteristic "audible click," allowing technicians to confirm proper trap cycling by ear.
• Durability: Highly resistant to the erosive effects of condensate and the thermal stress of superheated steam.
• Freeze Resistance: Suitable for outdoor installations when the trap is installed vertically with a downward discharge.

Common Questions

You should replace the disc if the trap is failing to close (blowing steam) or if the audible cycle has become erratic. Upon inspection, any visible pitting, erosion, or "wire-drawing" on the disc surface indicates it is time for a replacement.

No, the 55440 is specifically sized for the 3/4" NPT Spirax-Sarco TD52 and related thermodynamic models. Always verify the trap size and model number on the cap before ordering.

While the new disc is factory-lapped, the integral trap seat should be inspected. If the seat shows signs of wear, light lapping (up to 0.010 inches) may be required to ensure a proper seal with the new steam trap repair part.

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.