Tightness control type TC1-TC2-TC3

Every time the units are operated or shut down, the tightness control TC tests the functioning of both valves on units with two safety valves.
If an inadmissible leakage is registered at one of the gas valves the TC prevents the burn er from starting up.
The other valve continues to operate properly to ensure that the gas is safely shut off.
European stand-ards EN 746-2 and EN 676 call for tight-ness control tests for ratings in excess of 1200 kW.
According to EN 746-2 the pre-ventilation of the burner chamber is not re-quired under certain def ned con ditions if a tightness control is installed. In this case, venting to atmosphere is required.