Mcdonnell & Miller 354141 Long Barrel Probe

The McDonnell & Miller 354141, also identified as the PA-800-U Long Barrel Probe, is a critical sensing component engineered for high-performance water level detection in commercial and industrial HVACR applications. This extended barrel probe is designed specifically for use with the PS-801-U-120 and PS-802-U-24 low water cut-off (LWCO) series. As a veteran technician knows, maintaining precise conductivity levels is essential for boiler safety; this replacement probe utilizes advanced electrode technology to monitor water levels in cooling towers and steam boilers, preventing catastrophic dry-fire conditions. The 354141 probe features a durable Teflon insulator to prevent grounding issues and ensure electrical isolation from the boiler piping. With a weight of 1.2 lbs and a 3/4" NPT mounting, it provides a robust interface for liquid level controls. Regular inspection of the metal rod for scale build-up is recommended to maintain optimal sensitivity and system efficiency in any HVAC water level sensing setup.

• Precise Level Detection: Optimized for high-accuracy sensing in McDonnell & Miller PS800 series low water cut-offs.
• Industrial Durability: Features a long barrel design and Teflon insulation to resist fouling and accidental grounding.
• System Protection: Acts as the primary sensor to prevent dry-firing by ensuring the burner circuit is interrupted if water levels drop too low.
• Simplified Maintenance: Designed for easy removal and cleaning, ensuring minimal downtime during annual boiler inspections.
• Broad Compatibility: Direct OEM replacement for model PA-800-U, ensuring a perfect fit with existing 3/4" NPT connections.

Which low water cut-offs are compatible with the 354141 probe?
The McDonnell & Miller 354141 is the specific long barrel replacement for the PA-800-U assembly, primarily used with PS-801-U-120 and PS-802-U-24 controllers.

How do I clean the long barrel probe to prevent nuisance shutdowns?
To maintain HVACR sensor performance, wipe the metal rod and Teflon insulator with a non-abrasive cloth. Avoid using sharp tools that could scratch the insulator, which may lead to loose probe grounding or false readings.

What causes a "shorted probe" error on the LWCO display?
A shorted probe typically occurs when scale, oily residue, or boiler water chemistry creates a bridge between the probe rod and the boiler wall. Replacing a fouled unit with a new 354141 probe often restores reliable operation.

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.