Watts 0274683 3/4 In Bronze Boiler Pressure Relief Valve, 100 psi, Threaded Female Connections

The Watts 174A model 0274683 is factory set to relieve at 100 psi. It is a pressure-only relief valve (no temperature element), so it protects the boiler against overpressure alone. Max working temperature is 250 degrees F.

Yes. Both inlet and outlet are 3/4 inch female NPT, so it threads onto a 3/4 inch male nipple off the boiler tapping and takes a 3/4 inch male-threaded discharge pipe on the outlet.

No. A relief valve must be set at or below the boiler's maximum allowable working pressure, and the 0274683 is set at 100 psi. Typical residential hot water heating boilers need a 30 psi setting. The 174A series is offered across a 30 to 150 psi range, so order the version matching the boiler's rating plate. The 100 psi valve suits higher-pressure commercial boilers.

Its steam discharge capacity is 1,695,000 BTU per hour, so the boiler's rated input must be at or below that figure for the valve to relieve fast enough. Size off the boiler nameplate, not the pipe size.

No. The 0274683 is a boiler pressure relief valve, pressure protection only. Water heaters require a combination temperature and pressure (T and P) valve with an extension thermostat probe. Use this one on boiler applications.

Yes, the 174A 0274683 includes a test lever so a maintenance tech can manually lift the disc and flush the seat during routine checks without pulling the valve.

No valve of any kind goes between the relief valve and the boiler, and nothing restrictive goes on the discharge. The 0274683 has a 3/4 inch female NPT outlet, so run full 3/4 inch discharge piping, pitched to drain and terminated near the floor. Mount the valve vertically, upright.

Bronze body, made in the United States. Bronze holds up to boiler water chemistry and the 250 degree F service temperature better than a plated steel body, which matters on a valve that sits idle for years and still has to open.