SFO-PT20 Pressure Temperature Valve(P/T)

• PT valve is a pressure and temperature safety valve, for pressure-type solar water heaters (closed containers) and can protect system by temperature and pressure. It is a safety protection device for solar water heaters.

• In the tank of solar heating system, when water temperature rises, the volume of the water expands, and the pressure inside increases at the same time. PT valve has two working on modes, pressure and temperature.

2）When the temperature of tank increases to the set value, PT valve open then water drain out meanwhile cold water enters the tank to protect the solar water heating system by reduce temperature and pressure inside.

• PT valve opens when either temperature or pressure is met the set value.

• PT valve does not rely on any external force, but uses the force of the medium itself and the force generated by the thermal expansion of the temperature sensing element to overcome the load of the spring to open the valve flap,drain the rated amount of fluid to prevent pressure and temperature from exceeding the rated safety value.

• When the pressure and temperature return to normal, the valve closes again and prevents the media from continuing to flow out.

• PT valve pressure setting value selection is generally slightly less than the maximum pressure (Pmax) that the entire system can withstand. 0.6 MPa (6 bar) is generally selected in a solar water heating system.
• The pressure of PT valve cannot be the same as the normal operating pressure,too close to normal operating pressure can cause frequent pressure relief of the valve,reduce the valve's service life.
• Usually, it is recommended that the cold water inlet pressure be 0.25-0.3Mpa (2.5-3 bar).If the cold water inlet pressure is too high, we recommend to install a water pressure rregulator valve.（Water Pressure Rregulator valve）

• PT valve should be installed on the top or side of the water heater and the temperature sensing element must be completely immersed in water.
• PT valve can be installed horizontally or vertically and cannot be inverted.
• Install drain piping to avoid contamination of the tank surface.Drain pipe should be connected to floor drain or collector.
• When connecting the drain pipe, make sure that we can observe the drain.The drain pipe should be well protected against freezing and leakage, keep it clear and prevent blockage.
• A water pressure rregulator valve must be installed in the hot water system to prevent sudden increase in water pressure and affect the normal operation of the safety valve.
• Periodic inspection,the safety valve handle is swayed at least once a year, water leaves the handle and back to its original position,no water to indicate that the valve is invalid,it should be replaced immediately.
• Dirt will directly affect the operation of the valve, please use a clean water supply.Hard water areas need to increase the number of regular inspections.