Lochinvar 100170641 Limit Switch 100170641

The Lochinvar 100170641 Limit Switch is a critical safety component designed for high-performance hydronic systems, serving as the direct OEM replacement for the obsolete TST30010. Engineered with an operating range of 30-210°F, this auto-reset high limit switch monitors internal water temperatures to prevent catastrophic overheating in Lochinvar Copper-Fin II boilers and pool heaters. When temperatures exceed the 210°F threshold, the switch opens the circuit to the gas valve or control board, initiating a safety shutdown. As an automatic reset limit, it restores continuity once the system cools within the differential, though consistent tripping typically indicates a primary flow or scaling issue within the heat exchanger. This Lochinvar boiler limit switch is essential for maintaining the operational integrity of commercial and residential gas-fired equipment, ensuring the appliance remains within safe thermal parameters. For technicians servicing older units, this updated part number ensures full compatibility and precise calibration for Lochinvar HVAC replacement parts.

• OEM Compatibility: Exact replacement for legacy part numbers TST30010, TST3911, and TST4010, ensuring a drop-in fit for existing harnesses.
• Safety Regulation: Provides high-limit protection from 30°F to 210°F to prevent thermal stress on the copper heat exchanger.
• Automatic Reset: Reduces manual intervention by self-correcting after the temperature returns to a safe operating range.
• Broad Application: Validated for use in Lochinvar Copper-Fin II boiler models (CB 985-2065) and pool heaters (CS 985-2065).

Is the 100170641 a direct swap for the TST30010?
Yes, the 100170641 is the official current part number designated by Lochinvar to replace the older TST30010 limit control without requiring field modifications.

What causes this limit switch to trip frequently?
Frequent tripping usually indicates low water flow, a failing circulator pump, or significant scale buildup in the heat exchanger, forcing the water temperature above the 210°F limit.

Does this switch require a manual reset?
No, this specific model is an auto-limit switch. It will automatically close the circuit once the sensed temperature falls below the fixed differential, though the root cause of the overheat should always be investigated by a licensed contractor.

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.