McDonnell & Miller 318827 O-Ring

Maintain the integrity of your low water cut-offs with the McDonnell & Miller 318827 O-Ring. As a veteran technician, you know that a high-pressure steam environment demands precise sealing. This square cut O-ring, also recognized as Model 69-114, is the standard replacement part for the Series 69 Low Water Cut-Off and E-8 level controls. Transitioning from older gasket styles to this new style O-ring ensures a tighter, more reliable seal between the housing and the boiler nipple insertion tubes.

When performing annual maintenance or a teardown of a mechanical low water cut-off, replacing the elastomer components is non-negotiable to prevent nuisance leaks or steam discharge. The 318827 O-ring is specifically engineered to withstand the thermal cycling and chemical treatments found in commercial and residential steam boiler systems. By using genuine McDonnell & Miller replacement parts, you preserve the exact tolerances required for the float assembly to operate without friction, ensuring the burner circuit interrupts reliably if a low-water condition occurs.

Key Benefits:

• Direct Compatibility: Engineered specifically for Series 69 and Model 69-114 built-in controllers.
• Square Cut Precision: The square cut design provides superior surface contact compared to standard round O-rings, preventing bypass leaks under 20 PSI max steam pressure.
• Industrial Grade Material: Manufactured from high-temperature resistant elastomers to ensure boiler system sealing longevity.
• OEM Reliability: Eliminates the risk of improper fitment associated with generic HVAC replacement seals.

Common Questions:

Which systems use the 318827 O-ring?
This part is the primary seal for the McDonnell & Miller Series 69 mechanical low water cut-offs, typically found in 2-1/2" NPT boiler side tappings.

What is the difference between the old style and the new style 318827?
The current 318827 utilizes a square cut profile for enhanced sealing area, providing a more robust interface than the previous round-profile versions used in older 69 series assemblies.

Can I reuse my existing O-ring during a float inspection?
It is standard field practice to replace the O-ring whenever the insertion tube is pulled. Reusing an old elastomer that has been compressed and heat-set often leads to leaks once the assembly is re-torqued.

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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.