Brahma 37201221 MPI22 control box

The Brahma MPI22 37201221 gas controller belongs to a series of microcontroller-based devices that are also suitable for controlling forced-draft burners running on mixed oil and gas fuels for non-permanent operation.  The MPI22 is a new product, as each unit, in addition to performing all the typical functions of a burner, also includes a valve inspection system check program, which can be activated by simply pressing on request. Connecting only one control unit instead of two is certainly a technical and economic advantage. These controls perform non-volatile locking, i.e. restarting the system from the emergency shutdown state is possible only by manually resetting the control. Another feature is the ability to control various types of air dampers; in fact, due to the versatility of the control unit, the duty cycle required by the current standard is always observed. This control range is suitable for equipping multi-stage or modulating burners for domestic and industrial heating.

General characteristics

The main features of the Brahma MPI22 37201221 burner control unit are as follows:

− flame control due to the flame straightening (ionization) property or using UV1 type ultraviolet phototubes (technical specifications are given in the relevant technical data sheets);

− two independent safety contacts for controlling the gas valve;

− the service life of electrical equipment is max. declared load >250,000 operations;

− built-in and/or remote manual reset with liquid crystal indication of the reasons leading to an emergency shutdown;

− the ability to control the valve inspection system at the pre-purge stage or after purging;

− Easy to install and connect;

− the possibility of multiple ignition attempts depending on the final application;

− operating cycles compatible with the LFL1 type controller (Siemens). When replacing the control unit, the outlet should also be replaced.

Technical specifications

Power supply: 230 V (+10%/-15%) – 50/ 60 Hz; on request: 110/120 V (+10%/-15%) – 50/ 60 Hz

Operating temperature range: -20°C + 60°C

Ambient humidity: no more than 95%

Degree of protection: IP40

Classification codes:

according to EN 298:03 FBLLXN

according to EN 230:05 FTLLXN ”WLE”

Power consumption at startup: 7.5 VA

Power consumption during operation: 9 VA

The presence of a base: no

Pre-ventilation time (TV/tp): 20 sec

Safety time (ts): 3 sec

Tightness control of gas valves: yes

Weight: 0.95 kg

Dimensions: 10.3×10.3×9.1 cm

Construction

The use of special manufacturing technology and the introduction of SMT technology have made it possible to obtain an extremely flexible device that can control the air flap. The plastic housing protects the control panel from any damage resulting from accidents, careless handling, dust and dirt ingress. The varistor protects the control panel from power surges in the network. A built-in fuse protects the internal control relays in the event of a short circuit at the outputs (gas valves, motor, transformer and lock signal). Since this is not an emergency fuse available, the control unit must be protected by an external high-speed fuse suitable for connected loads and not exceeding 6.3A.

Operating mode

When the thermostats R, W and GP are closed, the device sends a command to start the engine of the first burner (M1) and, after the delay time (t7), also to the engine of the second burner (M2). After the delay t16 expires, the air flap is commanded to open up to max. air flow; as soon as the air flap is fully open, the control system checks the APS air pressure switch, and if the APS does not switch within time t10, the control system will perform a lockout. Otherwise, the cycle will continue taking into account the pre-purge time (t1). At the end of the pre-purge stage, the air flap is commanded to close to a minimum. the air flow, and the pre-ignition phase t3 (t3’) begins, at which the ignition transformer is activated. If at this stage the control unit detects a flame signal in the burner (for example, due to leakage from the fuel valves), it will perform a lockout within 1 second. If the pre-ignition stage is successfully completed, the safe time t2 (t2’) will begin, during which the control unit supplies power to the gas valve and maintains the operation of the ignition transformer. At the end of the process, during a safe time, the control system checks the flame signal; if no flame signal is detected, the control unit switches to lock mode. The second valve is switched on with a delay of t4 compared to the first valve, provided that a sufficient flame signal is detected. The start sequence ends after the delay t5 expires, when the air flap begins to adjust between the minimum and maximum air flow through the external LR control. At start-up, the air flap is checked to ensure that it is in the closed position (z); As soon as power is supplied to the M1 engine, the control system ensures that the air flap is in the fully open position (a) to ensure the best cleaning of the combustion chamber; before the start of the pre-ignition time, the control system gives the closing command to min. air flow (m); this state is maintained until the end of the ignition sequence, then the control unit sends a modulation command to the external LR device.

Patent/certification

− EC type certification (PIN code 0694BQ0913) in accordance with the Gas Appliance Directives 90/396 and 93/68;

− in accordance with the following standards:

− EN 298:03 (European standard for automatic ignition of gas burners and flame control systems);

− EN 676:03 (European standard for automatic forced-draft gas burners);

− EN 1643:00 (European standard for valve inspection systems);

− EN 267:99 (Forced draft oil burners);

− EN 746-1:97 (Industrial heat treatment equipment);

− EN 746-2:97 (Industrial heat treatment equipment);

− EN 230:05 (European standard for automatic flame control systems for oil burners).