Robertshaw 1720-801 Head Assembly

The Robertshaw 1720-801 is a critical TS-J Safety Magnet Head Assembly engineered for Unitrol gas valves utilized in residential and commercial water heating systems. Designed to facilitate precise thermocouple-to-valve connection, this drop-in replacement ensures the pilot flame monitoring circuit maintains system integrity during combustion cycles. In technical field applications, the 1720-801 operates on a millivolt signal generated by the thermocouple; any drop in voltage causes the magnet head to release, triggering an immediate safety shut-off of gas flow to the burner. This magnetic head for gas valves is compatible with various Robertshaw TSJ and Unitrol series valve bodies, providing a reliable mechanical interface that eliminates nuisance shutdowns caused by poor contact. When performing a water heater gas valve repair, technicians prioritize this assembly for its specific resistance tolerances and durable construction, ensuring pilot safety control remains stable under high-heat operational environments. Accurate seating of the magnet head assembly is vital for maintaining the continuity of the thermocouple circuit and preventing unauthorized gas leakage.

Key Benefits for Technicians:

• Compatible with high-volume Robertshaw 1720 series and TSJ series domestic water heater valves.
• Engineered for high-sensitivity millivolt response to ensure rapid safety shut-off upon pilot failure.
• Constructed with heavy-duty materials to prevent thread stripping and ensure a gas-tight seal at the manifold.
• Direct OEM replacement simplifies the thermocouple connection troubleshooting process during field service.
• Optimized for a wide range of BTU inputs across standard atmospheric vented water heating units.

Common Technical Questions:

How do I verify if the Robertshaw 1720-801 is faulty?
Perform a millivolt drop test using a multimeter; if the magnet fails to hold between 15-30mV while the thermocouple is heated, the head assembly likely requires replacement.

Is this magnet head compatible with electronic ignition systems?
No, the Robertshaw 1720-801 is strictly designed for standing pilot systems utilizing millivolt thermocouples and TSJ-style manual gas valves.

What causes a magnet head assembly to fail prematurely?
Corrosion at the thermocouple contact point, over-tightening of the lead wire, or excessive heat exposure can degrade the internal coil and lead to circuit failure.

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.