Spirax Sarco 1250990 MST21 Thermostatic Steam Trap 1/2" FNPT 518°F 304psig NSMP

Product Overview

Up for sale is a brand-new Spirax Sarco 1250990 replacement sub-capsule mechanism for the industry-standard **MST21 Series** stainless steel thermostatic balanced pressure steam traps. This precision fluid instrumentation component is custom-engineered to handle thermal loop modulation in commercial steam setups, lines, and heat tracing loops. Factory-calibrated for a **40 Degree Subcool profile**, the internal bellows capsule holds a thermal liquid mix that responds immediately to pressure changes, expanding to close the trap near steam saturation and contracting to discharge cooled condensate exactly 40°F (approx. 22°C) below saturation temperature. Excellent choice as a critical maintenance spare to prevent energy loss and water-hammer stress in institutional steam loops.

Technical Specifications

• Brand / Manufacturer: Spirax Sarco
• Part Number / MPN: 1250990
• Trap Compatibility Series: MST21 and MST21H Stainless Steel Thermostatic Steam Traps
• Component Profile: Thermostatic Balanced Pressure Replacement Bellows Capsule
• Nominal Size Fitment: 1/2-Inch NPT Pipe Layouts
• Thermal Subcool Rating: 40°F (Fahrenheit) Sub-Cool Configuration
• Operational Objective: Automatic non-condensible gas venting and condensate drainage control

Condition & Seller Guarantees

• Item Condition: New Surplus in Original Packaging (NSMP). This replacement capsule module is in brand-new, completely uninstalled condition. It has never been threaded into a trap body housing, piped into an active line, or exposed to high-temperature system scaling loops. It remains safely clean-preserved inside its original factory cardboard package box carrying the authentic identifiers pictured.
• Storage Practices: Maintained in a dedicated dust-shielded, climate-controlled warehouse layout to completely protect the internal precision bellows element and metal sealing edges from environmental moisture or oxidation.
• Manufacturer Support Disclaimer: Manufacturer's warranties and official direct technical support lines DO NOT apply to this item. Offered strictly as independent industrial pipeline distribution surplus replacement hardware overstock.
• Seller Warranty: We fully cover this steam trap hardware unit with our comprehensive 120-Day Seller Replacement/Refund Warranty protecting your plant maintenance loop or mechanical installation schedule against unexpected component faults.

Standard Shipping Logistics

• Expedited Shipping: Same-day shipping is available on most orders made before 4:00 PM EST. Orders finalized after this cutoff time slice will be securely processed and dispatched on the following business day to ensure minimum maintenance window or contractor layout downtime.
• Secure Parcel Packaging: The module inside its factory box will be securely surrounded with layers of protective cushioning film and packed safely inside an outer double-walled generic corrugated shipping box to guarantee clean, zero-movement transit conditions.
• Collect Carrier Account Billing: We can ship collect using the buyer's corporate UPS or FedEx account! To coordinate collect billing, please send us a direct message containing your verified shipping carrier account details, preferred service classification (e.g., Ground, Priority Overnight), and billing zip code prior to checking out.