Spirax-Sarco 72942 Thermostatic Trap

The Spirax-Sarco 72942 is a professional-grade 1/2" RTV-125 thermostatic steam trap engineered for precise condensate management in low-pressure and vacuum heating systems. Designed with a vertical pattern body, this balanced pressure steam trap utilizes a welded stainless steel thermostatic element—specifically the BP99 thermostat—which automatically adjusts to varying pressures. It is calibrated to discharge condensate approximately 23°F (13°C) below saturated steam temperature, preventing steam loss while ensuring efficient air venting during equipment start-up. Constructed with a rugged forged red brass body, the 72942 is built to handle a maximum operating pressure of 125 psig and temperatures up to 353°F. It features a 1/2" MNPT male union inlet and a 1/2" FNPT female outlet, making it an ideal drop-in replacement for legacy models like the TV-125. This unit is commonly deployed in radiator heating systems, hospital sterilizers, and commercial laundry equipment where reliable thermostatic radiator trap performance is critical to maintaining thermal efficiency.

• Automatic Pressure Calibration: The self-adjusting balanced pressure element eliminates the need for manual orifice changes across its entire operating range.
• High-Durability Internals: Features a stainless steel valve head and seat to resist erosion and extend service life in harsh steam environments.
• Simplified Maintenance: The vertical flow pattern and union connection allow for internal component replacement without disrupting the permanent piping assembly.
• Optimized Air Handling: Excellent air venting characteristics prevent air binding in radiators and heat exchangers, ensuring rapid system warm-up.

Is the Spirax-Sarco 72942 compatible with vacuum systems?
Yes, this model is specifically rated for operation in vapor or vacuum two-pipe heating systems, with a minimum operating pressure rating down to 25" Hg vacuum.

What is the difference between the RTV and RTH models?
The Spirax-Sarco RTV-125 features a vertical body pattern, whereas the RTH model utilizes a straightway pattern. Both share the same 125 psi pressure rating and stainless steel internals.

Can I repair this trap without removing the body from the line?
Yes. By unscrewing the brass cap, the BP99 thermostatic element and seat can be inspected or replaced using a standard repair kit while the body remains installed.

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.