Watts 140S3-150210 3/4 3/4 In Bronze Automatic Reseating Temp And Pressure Relief Valve, 150 psi, 210 degree F, 3 In Thermostat, Female Connections

Yes, both ends are 3/4 inch female NPT threaded, inlet and outlet. That means it screws onto a 3/4 inch male NPT nipple at the heater's relief tapping, and the discharge side takes a 3/4 inch male-threaded pipe or adapter running to the drain. It will not mount to a 3/4 inch female tapping without a nipple, since the valve itself is female on both sides.

Sizing on a T&P valve is done against the appliance input rating, and this one is rated 180,000 BTU per hour on temperature discharge and 1,437,600 BTU per hour on pressure steam discharge. The number that governs a water heater is the temperature side: the valve must be rated at or above the heater's input. So it suits appliances up to 180,000 BTU/hr input. A larger commercial heater above that needs a higher-capacity valve.

No. The 140S3-150210 is not a lead free valve, so it should not go on potable water lines in jurisdictions enforcing the lead free requirement for drinking water. Use it on non-potable service, heating, or storage applications instead, and specify a lead free T&P model where potable code applies. The body is bronze.

Yes. The Watts 140S3-150210 is flagged Buy American Act compliant with USA origin, which is what a federal, state, or institutional spec typically asks for on a plumbing submittal. Watts part number is 254702.

Maximum working pressure is 113 psi, with the valve set to relieve at 150 psi. In practice that means the system it protects should be running comfortably under 113 psi in normal operation. If your building's incoming pressure is running higher than that, the fix is a pressure reducing valve on the service, not a higher-set relief valve.

For 3/4 inch female NPT openings on non-potable or heating service, with heaters rated 150 psi and up to 180,000 BTU/hr input, the 140S3-150210 is a reasonable single stock item. The three things that break standardization across a fleet: tapping size other than 3/4 inch, a required probe length other than 3 inch, and any heater whose nameplate pressure is below 150 psi. Walk the mechanical rooms and check those three against the nameplates before you commit to one part number.

Automatic reseating means the valve closes itself once pressure or temperature drops back below the setpoint, rather than staying open or requiring a manual reset. It is a self-relieving safety device, not a one-shot. That said, a valve that has discharged repeatedly is telling you something upstream is wrong, usually thermal expansion with no expansion tank or a failed thermostat on the heater, and a valve that weeps after reseating should be replaced.