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Manufacturer Resources
Product Specs
- Application:
- Boiler
- Body Material:
- Iron
- Country Of Origin:
- United States
- Inlet Connection Size:
- 1 1/4 IN
- Inlet Connection Type:
- Female Threaded
- Inlet Thread Type:
- NPT
- Maximum Temperature:
- 250°F
- Maximum Working Pressure:
- 20
- Outlet Connection Size:
- 1 1/2 IN
- Outlet Connection Type:
- Female Threaded
- Outlet Thread Type:
- NPT
- Pressure Range:
- 30 to 75 PSI
- Pressure Relief Setting:
- 30 PSI
- Pressure Steam Discharge Capacity:
- 2,105,000 BTU per hour
- Protection Type:
- Pressure
- Series:
- 740
- Test Lever:
- Yes
- Department:
- Plumbing
- Product Group:
- Plumbing
- Product Subgroup:
- Valves
- Product Type:
- Relief Valve
Watts 383020 – Frequently Asked Questions
1) What size pipe does the Watts 740 Series 0383020 boiler relief valve connect to?
Inlet is 1-1/4 inch female NPT and the outlet is expanded to 1-1/2 inch female NPT. That expanded outlet is why the discharge pipe off this valve is a size larger than the tapping it screws into, so plan on 1-1/2 inch pipe running to the drain, full size the whole way and no reduction.
2) Is the Watts 0383020 set at 30 psi, and can that setting be changed?
It comes set at 30 psi, which is the standard setting for a residential or light commercial hot water heating boiler. The 740 Series covers a 30 to 75 psi range across the family, but the setting is fixed at the factory for each model, so if your boiler needs a higher set point you order the model built for that pressure rather than adjusting this one.
3) Will this Watts relief valve protect a steam boiler or only a hot water boiler?
This is a pressure-only relief valve for hot water heating boilers. It has no temperature element, so it is not a T and P valve for a water heater, and it is not an ASME steam safety valve. The 2,105,000 BTU per hour figure on it is a steam discharge capacity rating, which is how relief capacity on this type is published, not an indication that it is intended as a steam boiler safety valve.
4) How do I know a 2,105,000 BTU relief valve is big enough for my boiler?
Match the valve's relieving capacity to the boiler's gross output, not the input or the connected load. This one relieves 2,105,000 BTU per hour, so it covers any boiler whose rated output is at or below that. If the boiler output exceeds it, you either move up in valve size or use multiple valves. Undersizing here is the one mistake that matters on a relief valve.
5) Can I use this iron-body Watts relief valve on a domestic water heater?
No. The iron body and the pressure-only design make it a hydronic boiler valve. A domestic hot water heater needs a bronze T and P relief valve that senses temperature as well as pressure and is rated for potable water. Putting this on a water heater leaves the tank without temperature protection.
6) What is the maximum temperature the Watts 0383020 relief valve can handle?
Rated to 250 degrees F, which is above the operating range of any hydronic heating boiler running on a 30 psi system. The body is iron, so it is built for a closed heating loop, not for potable water service.
7) Does the Watts 0383020 have a test lever for annual maintenance?
Yes, it has a manual test lever. That lets a maintenance tech lift the disc off the seat once a year to confirm the valve is free and clear of scale buildup, which is the standard check on a boiler relief valve. Do the test at normal system pressure and be ready for hot water at the discharge.
8) Is the Watts 740 Series relief valve made in the USA for government or institutional specs?
Country of origin is the United States, which matters on public work and institutional purchasing where domestic sourcing is written into the spec. It is a Watts 740 Series iron boiler relief valve, part number 383020.
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Does the Watts 383020 come with a warranty?
Absolutely. The Watts 383020 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
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