Weil-mclain 381-800-878 Pin Stem Assembly EG-55 Series 7 Steam Boiler Without Vent Damper

Product Description

The Weil-McLain 381-800-878 is a Pin Stem Assembly designed for use with EG-55 Series 7 residential cast iron steam boilers configured without a vent damper. This replacement part is a critical mechanical component that functions within the boiler's gas valve and control linkage system. It helps maintain proper alignment and actuation of internal components, ensuring the boiler operates safely and efficiently. Licensed HVAC technicians and heating contractors rely on OEM replacement parts like this to restore boiler systems to factory specifications. Using the correct pin stem assembly matters because a worn or damaged component can cause improper valve seating, erratic ignition sequencing, or system lockout conditions that interrupt heat delivery. The EG-55 Series 7 is a floor-mounted, gas-fired cast iron steam boiler rated at 200 MBH input and 167 MBH DOE heating capacity, with an AFUE rating of 82 percent. It uses electronic intermittent ignition and a stainless steel non-linting pilot burner. The boiler carries certifications from CSA, ASME, AHRI, and DOE, and is designed to meet strict residential heating codes. The 381-800-878 is manufactured specifically for units without a vent damper, so verifying the boiler configuration before ordering is essential. This part is intended for installation by a licensed and qualified heating professional in accordance with Weil-McLain installation instructions, local codes, and applicable industry standards. Warranty and technical support are handled exclusively through licensed contractors. Keeping original Weil-McLain parts in stock helps minimize system downtime during the heating season, which is especially important for steam boiler systems serving residential occupants. HVAC service technicians, boiler mechanics, and heating equipment wholesalers frequently source this type of OEM assembly for scheduled maintenance and emergency repair work.

• OEM pin stem assembly for Weil-McLain EG-55 Series 7 cast iron steam boilers
• Designed for boiler configurations without vent damper — verify unit configuration before ordering
• Supports proper mechanical function of gas valve and control linkage components

Product Highlights

The Weil-McLain 381-800-878 Pin Stem Assembly is a direct OEM replacement for EG-55 Series 7 steam boilers without vent dampers, helping licensed heating professionals restore system performance to factory specifications quickly and reliably.

Product Information

Standard Information

• Brand: WEIL-MCLAIN
• Manufacturer Part Number: 381-800-878

Technical Specifications

• Compatible Boiler Series: EG-55 Series 7
• Vent Damper Configuration: Without Vent Damper
• Boiler Type: Steam
• Fuel Type: Natural Gas
• AGA Input Rating: 200 MBH
• DOE Heating Capacity: 167 MBH
• Net IBR Rating: 125 MBH
• AFUE Rating: 82 Percent
• Ignition Type: Electronic Intermittent
• Burner Type: Stainless Steel, Non-Linting Pilot
• Heat Exchanger Material: Cast Iron
• Mounting Type: Floor Mount
• Vent Size: 7 inches
• Venting Type: Automatic
• Supply Connection: 3 inches Threaded
• Return Connection: 2.5 inches Threaded
• Gas Connection: 0.5 inches
• Pressure Rating: 50 PSI
• Relief Valve: 15 PSI ASME Relief Valve Supplied
• Applicable Standards: CSA, ASME, AHRI, DOE
• Warranty: 10 Year Limited (Heat Exchanger), 2 Year Limited (Other Parts)