The Watts brand thermal safety valve is used to protect boilers from overheating. This specific valve is suitable for both open and closed system fireplaces. The Watts STS-20 cooling valve is a thermostatic valve that protects various types of boilers and fireplaces using solid fuels such as coal, coke, wood, or briquettes from the possibility of overheating in a Central Heating system.

Valve technical parameters:

• Connection type: 1/2" internal thread
• Opening temperature: 97°C
• Maximum flow rate: 6.5 m³/h

How does the thermal protection work?

The Watts STS 20 valve has a sensor located in the rear part of the boiler and operates to protect the boiler from overheating in the following way: if the water temperature reaches above 95°C, the valve allows water from the plumbing installation to flow into the spiral cooler. The spiral cooler absorbs excess heat, and the water is discharged into the sewage system.

The valve is adjusted to open at a sensor temperature of 97ºC. The valve setting is fixed and cannot be changed by the user. As the temperature around the sensor rises, the sensor filling also heats up, causing an increase in pressure. This pressure is transferred to the housing through a capillary and acts on the valve. At a sensor temperature of 97ºC, the pressure in the housing becomes greater than the spring pressure of the valve, causing the stem to lift and open the valve.

Advantages

• Does not require power supply - self-acting valve
• Opens with an increase in sensor temperature
• Brass and other materials in contact with water suitable for drinking water contact
• Thermostatic element permanently integrated with the valve body to eliminate the risk of adjustment displacement
• Double sensor for reliable operation
• Capillary protected against bending by a steel cover
• Space-saving compact solution

The valve must not be exposed to direct fire.

Failure to follow this recommendation may result in valve damage and loss of warranty.

Construction

1. Immersion probe with two sensitive elements
2. Probe sheath
3. Sheath connection
4. Capillary protection
5. Drain pushbutton
6. Expansion bellows
7. Rotating retaining pin
8. Valve body
9. Disc cap
10. Disc spring
11. Disc
12. Setpoint temperature on disc cap