One-way JBV thermostatic valve with a WZS-2 cooling coil (safety heat exchanger) is a solution used in closed water central heating systems without expansion vessels.

WZS-2 safety heat exchanger and the JBV thermostatic valve protects the boiler or furnace and the water installation of the central heating system from extensive heat (water boiling). The solution is effective and safe, because it does not require electricity to operate. Surface of the WZS-2 cooling coil is 0.17 m² allowing a cold water flow of 15 l/m.

Thermostatic JBV valve and WZS-2 safety heat exchanger working principle

• Excessive temperature rise is recorded by the JBV thermostatic sensor screwed on the output of the heating water knee connecting the boiler cooling coil and opens the thermostatic valve.

• The opening of the thermostatic valve causes the cold water from the water supply flowing through the cooling coil. The coil absorbs the heat from the central heating system, preventing water boiling and damaging the boiler or the central heating system itself.

• At the outlet of the cooling coil the received hot water can be drained (water outflow).

• Temperature dropdown to safe levels will cause the thermostatic valve to close automatically.

Securing the central heating water with JBV thermostatic valve and WZS-2 with cooling coil will keep the state of the working medium in the heating system (or other heat transfer fluid) in an unchanged condition despite the occurrence of the emergency operating mode - boiler and central heating system cooling.

The Cooling circuit is separated from the heating medium circuit.

WZS-2 safety heat exchanger wit cooling coil and single-function (one-way) thermostatic valve (cools the entire system when the water temperature exceeds for eg. 97 degrees Celsius, do allowing the water into the system). In some boilers or furnaces, the cooling coil is already built in. Atmos, Orlan Super or it can be inserted after additional charge: Dakon Dor, Ogniwo S6WC 12,6-20kW.

In other central heating steel boilers and all cast iron boilers, the cooling coil must be plugged in into the system as a separate item.