McDonnell & Miller AP-3-SS-J Probe Rod

The McDonnell & Miller AP-3-SS-J (Part Number 176231) is a heavy-duty, 39-inch (991mm) stainless steel probe rod designed for high-precision liquid level sensing in commercial and industrial boiler applications. Engineered for compatibility with conductance-type level controls, this ambient probe provides the critical conductive path required for low water cut-off (LWCO) and pump control sequencing. In the field, its 300-series stainless steel construction ensures superior resistance to corrosion and scaling, maintaining reliable signal integrity even in harsh hydronic environments.

For custom installations, this 39-inch replacement probe rod can be field-cut to meet specific tank depths or boiler manifold requirements. As a direct OEM replacement part, it integrates seamlessly with McDonnell & Miller RS-1-LP and Series 150E sensors, eliminating the common nuisance tripping associated with fouled or degraded electrode surfaces. Whether used for steam boiler safety or potable water level management, the AP-3-SS-J provides the rugged performance professional contractors expect from Xylem brands.

• 300-Series Stainless Steel: Provides maximum durability against chemical treatment and oxidation in high-temperature applications.
• Field-Adaptable Length: The 39-inch rod can be trimmed to exact specifications for precise secondary LWCO positioning.
• Conductance Reliability: Optimized for use with advanced boiler level controllers to ensure accurate "burn-on" and "burn-off" signals.
• Direct OEM Fit: Ensures proper threading and electrical contact within the probe housing, reducing installation labor.

Can I cut the AP-3-SS-J probe rod to a shorter length?
Yes. Professionals frequently cut these rods to match the specific low-water safety line of the vessel. Ensure you remove any burrs from the cut end to prevent localized scale buildup or electrical interference.

Is this probe rod compatible with glycol-water mixtures?
This probe is designed for use in conductive liquids, including water/glycol mixtures up to 50% concentration, provided the control unit is calibrated for the resulting fluid conductivity.

Does this probe require regular maintenance?
Technicians should inspect the rod annually for scale or oil residue. While the 176231 is highly resistant to fouling, mechanical cleaning with a non-abrasive cloth ensures the continuity required for safety circuit operation.

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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.