McDonnell & Miller 354083 Short Probe

The McDonnell & Miller 354083 (Model PA-RB-122) is a 3/4" NPT replacement short probe designed specifically for the RB-122 series low water cut-off (LWCO). This OEM replacement part is essential for maintaining the integrity of hydronic boiler systems. It features a self-cleaning tip engineered to reduce mineral scale buildup, ensuring consistent signal conductivity and preventing nuisance boiler shutdowns. When replacing a fouled or damaged probe, the M&M 354083 provides the precise resistance matching required for the RB-122 control board. Proper boiler probe maintenance requires a secure 3/4" NPT connection to prevent leaks while maintaining a clear electrical path to the water. This liquid level sensor probe is built to withstand high-temperature hydronic environments, providing reliable low water protection for residential and commercial heating applications. Always verify the probe length against the manifold clearance to ensure proper seating within the water column.

• Self-cleaning probe tip minimizes scale accumulation and maintenance intervals.
• Exact OEM replacement for the RB-122 Series ensures full electronic compatibility.
• Precision-threaded 3/4" NPT brass housing for a durable, leak-free installation.
• Restores reliable low water cut-off sensing to protect the heat exchanger from dry-fire conditions.

Is this probe compatible with the RB-120 series?
No, this short probe is specifically rated and calibrated for the RB-122 series. For RB-120 compatibility, verify the specific model number required by the control unit to ensure proper resistance values.

Does this probe require PTFE tape for installation?
While a 3/4" NPT connection requires a seal, excess tape can insulate the boiler probe from the ground, causing sensor errors. Use a conductive pipe dope sparingly to maintain electrical continuity.

Can I clean the probe instead of replacing it?
If the self-cleaning tip or the insulation is cracked or the pitting is severe, cleaning will not restore the signal. In these cases, a 3/4" NPT replacement probe is necessary to ensure safety circuit reliability.

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.