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

It opens at 30 psi. That is a fixed factory setting, not adjustable in the field, and 30 psi is the standard setting for a residential or light commercial hot water heating boiler. Check the ASME plate on your boiler first: the relief valve setting must not exceed the boiler's maximum allowable working pressure. If the boiler is rated higher and the system needs a higher setting, the 174A family is built in settings from 30 up to 150 psi, so you would order the matching setting instead of this one.

No. The 174A-030 is not lead free, so it is a heating boiler valve, not a potable water valve. Use it on a closed hydronic heating loop only. For a domestic water heater or any line feeding drinking water, you need a lead free T and P relief valve with both a temperature probe and a pressure element. The 174A is a pressure only device, with no temperature element at all.

Sometimes, but check the cause first. A 30 psi valve that weeps usually means system pressure is actually reaching 30 psi, which points at a waterlogged or failed expansion tank, a fill valve feeding past its setting, or a leaking domestic coil pushing city pressure into the loop. Swapping in a fresh 174A-030 fixes a valve whose seat has been cut by debris; it will not fix a pressure problem, and the new one will drip too. If the old valve is the same 1 inch NPT and 30 psi setting, this is a direct like for like replacement.

250 degrees F maximum. That covers any standard hot water heating boiler, which normally runs a high limit around 180 to 200 degrees F, with margin left over. The body is bronze, so it holds up in a hot wet hydronic environment better than a plated steel part and will not gall onto an iron nipple the way some materials do.

Yes, it is flagged Buy American Act compliant, country of origin USA. That matters on federally funded work, GSA jobs, and a lot of school district, municipal, and VA specifications where domestic sourcing is a line item on the submittal. Bronze body, 1 inch NPT, 30 psi setting, so it drops into a standard boiler tapping without a spec deviation request.

The 174A is ordered by two things: connection size and relief setting. In 174A-030 1, the 030 is the 30 psi opening pressure and the 1 is the 1 inch NPT connection size. Watts part number 274934. Settings across the 174A family run from 30 to 150 psi, so if the boiler nameplate calls for a different pressure you change the number in the middle, not the series. Get the setting wrong on the low side and the valve weeps every time the system comes up to temperature.

Nothing ships attached, so plan on a 1 inch male NPT nipple into the boiler tapping and a 1 inch discharge line. The discharge pipe has to be full size the whole way, run downward, terminate near the floor, and have no valve, no reducer, and no threaded end at the outlet. Mount the valve vertical, test lever up. Do not thread anything into the outlet that could restrict flow, since the 1,005,000 BTU per hour relieving capacity assumes an unobstructed 1 inch path.