Watts 174A-030 1 1/4 1 1/4 In Bronze Boiler Pressure Relief Valve, 30 psi, Threaded Female Connections

Both the inlet and outlet on the Watts 174A-030 are 1-1/4 inch female threaded NPT. So it threads directly onto a 1-1/4 inch male NPT tapping on the boiler, and the discharge side takes 1-1/4 inch male NPT pipe run down toward the floor. No adapters needed if your boiler tapping is already 1-1/4 inch NPT.

It is factory set to relieve at 30 psi, which is the standard setting for a residential or light commercial low pressure hot water heating boiler. The 174A series as a whole covers settings from 30 to 150 psi, so if your boiler nameplate calls for a higher maximum allowable working pressure you want a different setting in the series, not this one. Match the valve setting to the boiler MAWP on the nameplate; it must not exceed it.

Pressure only. The 174A-030 protects against overpressure and has no temperature sensing element, so it is the valve for a hot water or steam heating boiler, not for a domestic water heater. A water heater needs a combination T and P relief valve with an extension probe that trips on temperature as well.

No. The 174A-030 is not lead free, so keep it on closed loop hydronic heating and steam service. Anything touching drinking water needs a lead free rated valve instead.

Rated steam discharge capacity is 1,682,000 BTU per hour. Size the valve so its capacity equals or exceeds the boiler's gross output rating; on a boiler with a higher input than that figure you need a larger valve or multiple valves.

Yes. The 174A-030 is flagged Buy American Act compliant with USA origin, which is what a federal, school district, or municipal spec usually asks for on boiler room trim.

Order model 174A-030 in the 1-1/4 inch size; the Watts part number is 275600. Confirm you are getting the 1-1/4 inch version, since the 174A-030 designation is used across several connection sizes and only the size code separates them.

Maximum operating temperature is 250 degrees F, which covers normal hot water heating boiler operation and low pressure steam. The body is bronze, so it stands up to the wet cycling of a boiler tapping better than a plated steel part.