Automatic gas burner control MPA 50.01, MPA 50.02 Dungs

• These automatic burner controls MPA 50.01, MPA 50.02 are designed for intermittent operation of operating gas burners without blower, with integrated valve proving system and exhaust gas flow monitoring.
• Function: When the temperature controller issues a request for heating, gas safety valve V1 is opened after a 10-second startup delay. The gas pressure switch must indicate the presence of the required gas pressure within 1 second. The ignition is then switched on and the ignition gas valve ZV is opened after the set pre-ignition period (0-2 s) has elapsed. Depending on programming, the ignition is switched off when the presence of the flame is indicated (if the flame goes out within the startup safety period SZA1, the ignition is switched on again immediately) or at the end of the set 1st safety period SZA1 (2-30 s). With a flame present, the main gas valve V2 is opened after the set stabilising time (2-60 s) has elapsed. If Mode 2 is set, the ignition gas valve ZV is re-closed after the set initial safety period SZA2 (2-10 s) has elapsed. In Mode 1, the ignition gas valve remains open until a controlled shutdown takes place. If a flame is not detected after SZA1 or SZA2, the gas valves are deactivated and self-lock or lock out in the fault state. In the event of flame during operation, all gas valves (SZB) are deactivated within the operating safety period (SZB). The burner then switches to the fault state or a restart is attempted. If the presence of a flame is signalled before gas is released, the automatic burner control locks out in the fault state. If the burner is set for operation without a valve proving system, all gas valves are closed when the controlled shutdown takes place.
• Valve proving system: When the burner is operated in combination with a valve proving system, first gas safety valve V1 and 1 second later the main gas valve are closed when a controlled shutdown takes place. A flame or gas pressure should no longer be present. During test period V1 (1-60 s), the switch contact of the gas pressure switch is monitored as a safeguard against reclosing. Gas safety valve V1 is subsequently opened for 1 s to check for the presence of gas pressure. The switching contact of the gas pressure switch is then monitored over the set period V2 (1-60 s) as a safeguard against reclosing. If the leakage check is passed successfully, the MPA 50.02 switches to start-up wait state and can be restarted when the next request for heating is issued, provided that the restart lockout period (0-60 min) has elapsed. If a leak is detected, MPA 50.02 self-locks or locks out in the fault state. When the burner is commissioned, after a power fail or when the burner is restarted after a fault, the valve proving system is also activated during the startup phase.
• Gas pressure monitoring: If the gas pressure switch does not signal the presence of gas pressure after V1 is opened, a further 2 startup attempts are performed at 2-minute repeat intervals. If the third startup attempt is unsuccessful, the repeat interval is set to 1 hour.
• Fault unlock: Once the cause of the fault has been rectified, the fault shutdown of the MPA 50.02 can be cancelled by switching off the power supply (volatile lockout) or by pressing the Reset button on the display unit (non-volatile lockout) depending on the programming.