Product Overview:
Regulating fuel admission in self-powered heating systems, low-capacity millivolt gas valves maintain steady manifold pressure without external line voltage. The Robertshaw 710-508 Natural Gas Valve Millivolt 3/8" X 3.5" manages natural gas fuel delivery within applicable heating systems. Operating on self-generated millivolt current, this compact combination valve integrates manual control, pressure regulation, and safety shut-off functions into a single assembly. It regulates fuel supply to maintain a calibrated WC pressure setting across heating demand cycles in hearth products, wall heaters, and unvented room heaters.
Fuel Flow Control:
Through its internal control mechanism, the valve regulates gas passage according to the operating condition established by the heating system. The mechanism responds to the applicable control signal and changes the fuel-flow condition within the valve. This coordinates gas availability with the connected burner circuit.
Combustion Safety Interlock:
Positioned directly within the fuel supply line upstream of the burner, the valve serves as a primary safety interlock in the millivolt control loop. The valve operates in series with pilot safety circuits and wall switches or thermostats and remains locked out if pilot flame verification is lost. When operating normally, the valve permits natural gas delivery during calls for heat and closes immediately upon loss of millivolt current or pilot outage.
Replacement Guidelines:
Replacement may be appropriate when internal magnetic operators fail, mechanical valve seats stick, or internal regulator diaphragms deteriorate and affect the gas-control function. For the Robertshaw 710-508, relevant conditions may include failure to open when millivolt current is present, erratic 3.5" WC pressure regulation, or failure to stop gas flow when de-energized. Replacing the valve restores the intended pressure regulation, manual shut-off, and millivolt-actuated gas-flow control functions.
Common Failure Symptoms:
- Main burner failing to ignite despite a fully established pilot flame generating proper millivolt output.
- Unstable burner flame patterns caused by fluctuating 3.5" WC manifold natural gas pressure.
- Inability of the pilot magnet safety circuit to hold in after pressing and releasing the control knob.
- Gas valve remaining closed due to internal mechanical linkage binding or corrosion.
- Intermittent burner shutdown during heating cycles caused by magnetic operator failure.
Equipment Compatibility:
The Robertshaw 710-508 applies to specific heating units produced by the manufacturer. Before purchasing, verify that the application matches the exact attributes listed in the Technical Specifications table, including the brand, part number, product type, connection size, fuel type, control system, and pressure setting.
Technical Specifications:
Brand: Robertshaw
Part Number: 710-508
Product Type: Natural Gas Valve
Activation Type: Millivolt
Size: 3/8"
Gas Size: 3.5"
Loyalty Program
