Water Heater Info

The WATTS 210 Automatic Gas Shutoff Valve


In this blog, we will be talking about the Watts 210 automatic gas shutoff valve. Most people have never heard of this valve, so we thought it would be a good idea to explain what it is and what it does to help potentially lessen the damage from a malfunctioning water heater.

While many are aware of the temperature and pressure relief valve (T&P valve) on their water heater and what it does, the Watts 210 automatic gas shutoff valve isn’t as common and thus isn’t as well known. Basically, the Watts 210 is an immersion-type valve used to protect against overheating water in a water heater. The valve is installed where the T&P would normally be installed on a water heater and it has a thermostat that goes inside the water heater. The gas line is run into the Watts 210 from the gas source and then run from the Watts 210 to the gas control on the water heater.


The Watts 210 is a self-contained device that includes a manual reset button, a trip latch assembly and a thermostat. As we stated earlier, the valve is installed where the T&P valve would normally be installed on the water heater. The thermostat on the valve itself goes into the water heater and is set for 210 degrees. That means that if the temperature of the water in the water heater rises above 210 degrees, the valve shuts off the gas supply to the water heater. This helps to stop the temperature from getting any hotter in the water heater and helps to reduce any further damage to the water heater and possibly even the surrounding area if the water heater failed due to the increased thermal expansion.

As we said, the Watts 210 is installed where the T&P is located and then typically a T&P valve is installed on the cold water line outside of the residence, often right near where an outside faucet may be located. This is done because even though the Watts 210 shuts off the gas, there still needs to be a relief valve located somewhere on the water line to reduce the possibility of damage to the water heater and the water pipes themselves.

At this point, you may be wondering: If the Watts 210 shuts off the gas supply and acts as a T&P, why aren’t they part of a standard installation? The reason is twofold: First, the T&P works just fine as the main source of relief in the case thermal expansion occurs. Second, the part itself is not cheap and involves more labor and time, which can add a substantial amount to a standard water heater installation. The Watts 210 automatic gas shutoff valve is typically used if the T&P line cannot be run to the exterior of the residence as required by many state plumbing codes, especially in California. We often see this when the water heater is located in an inside closet such as in a hallway or the kitchen. In this situation, the water that comes out of the T&P has nowhere to go and can cause water damage if it is a substantial amount of water and goes undetected. In that case, a Watts 210 automatic gas shutoff valve is recommended.

As always, if you have any questions about this subject or your water heater in general, please call us 24 hours a day, seven days a week at 1-866-WHO-QUICK (946-7842). We are always happy to answer any questions you may have or even schedule an appointment for one of our water heater technicians to come and take a look at your water heater.

2 comments to “The WATTS 210 Automatic Gas Shutoff Valve”

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    • Hi Leo,
      It will depend on the condition of the part it’s self. We generally do not recommend re-using gas parts because of potential gas leaks, but each situation is different. If it is an older part or has wear in the fittings, I would recommend replacing it. Thank You for your question.

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