Watts 40XL-7-150210 1 1 In Bronze Automatic Reseating Temp And Pressure Relief Valve, 150 psi, 210 degree F, Test Lever, 8 In Extension Thermostat

The connections are 1 inch NPT, male on the inlet and female on the outlet. It threads into a 1 inch female T&P tapping on the heater, and the outlet takes a 1 inch male drain line down to within six inches of the floor or to an approved receptor.

The 40XL-7-150210 carries an 8 inch copper extension thermostat, which is meant for tanks where the sensing element has to reach past thick insulation or a deep tapping to sit in the hot water. On a heater prepped for a short shank probe, an 8 inch element can bottom out or foul the dip tube, so measure the tapping depth against the tank interior before you thread it in. Shorter probe lengths exist in the same 40L family if 8 inches is more than the tank will take.

No. The 40XL-7-150210 is a bronze body valve and is not a lead free model, so it does not meet the weighted-average lead content rule that applies to potable water components in states enforcing it. For potable domestic hot water in those jurisdictions, specify a lead free T&P valve. This one is still used on non-potable and commercial heating applications where the lead free rule does not apply.

Size it by BTU input, not by gallons. The valve is rated 2,135,000 BTU/hr pressure steam discharge and 500,000 BTU/hr temperature steam discharge. The temperature figure is the governing one on a water heater, so the appliance input has to be at or below 500,000 BTU/hr for this valve to protect it. Anything larger needs a bigger relief valve or a second one.

Neither, it is combination temperature and pressure. That is what a storage-type water heater requires, since the tank has to be protected from both thermal expansion pressure and runaway temperature. A pressure-only relief valve, the kind used on an expansion tank or a boiler feed line, will not satisfy a T&P tapping on a heater.

It is an automatic reseating temperature and pressure relief valve, so once the tank drops back under 150 psi and 210 degrees F it closes on its own. It also has a manual test lever so maintenance staff can exercise it on a schedule. If it weeps continuously after tripping, debris on the seat is the usual cause and the valve gets replaced rather than rebuilt.

It is flagged Buy American Act compliant with USA country of origin, which is what a federal, state, or institutional spec usually asks for on plumbing components. The Watts model number to put on the submittal is 40XL-7-150210 1.