McDonnell & Miller 302500 Gasket

The McDonnell & Miller 302500, also identified by model number CO-11, is a high-performance Sylphon base gasket engineered for a precise seal in steam and hydronic applications. Designed specifically for compatibility with Series 63 and E-28 low water cut-offs, this six-hole replacement component facilitates a leak-proof interface between the bellows assembly and the float head chamber. In the field, maintaining the integrity of the LWCO replacement parts is critical for preventing the escape of steam or system fluids, which can otherwise lead to pressure drops and compromised boiler safety protocols. Veteran technicians recognize the CO-11 gasket as the industrial standard for refurbishing McDonnell & Miller 63 series units, ensuring that the critical bellows mechanism operates without interference from external contaminants or pressure loss. Using an OEM boiler gasket replacement like the 302500 ensures exact bolt-hole alignment and thickness specifications, directly supporting the mechanical responsiveness of the low water cut-off system.

• Verified Compatibility: Exact fit for McDonnell & Miller Series 63 and E-28 low water cut-off assemblies.
• Precision Engineering: Features a six-bolt pattern designed to match CO-11 technical specifications for immediate seating.
• System Reliability: Creates a robust seal for the bellows assembly, preventing dangerous steam leaks and ensuring accurate float operation.
• Industrial Durability: Constructed from materials capable of withstanding the high-pressure and high-temperature environments of commercial steam boilers.

Is the CO-11 gasket interchangeable with other McDonnell & Miller series?
No, the McDonnell & Miller 302500 is specifically sized for the Series 63 and E-28. For Series 64 or 67, you must verify the specific part number in the manufacturer's service parts catalog to ensure a proper seal.

What are the signs that a Sylphon base gasket needs replacement?
Visible moisture or steam escaping near the bellows base, or mineral buildup (calcification) around the flange, indicates the seal has failed. A compromised gasket can lead to "short-cycling" or failure of the low water cut-off to trip the burner circuit.

Should I use sealant or RTV when installing the 302500 gasket?
Standard HVACR field practice dictates that this Sylphon base gasket should be installed on clean, dry flange surfaces. Ensure all old gasket material is removed from the head chamber and bellows base to prevent uneven compression and potential leaks.

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.