If during initial powering of the MC200CAB/4 the display exhibits a blank screen or random letters or the buttons are not functioning correctly, it may be due to a few reasons that could easily be rectified.
Procedure
WARNING: The next section must be carried out by a qualified person to current IEE regulations for Electrical Installations and any local regulations which apply.
WARNING: Always switch off and disconnect electricity supply to the controller and the heater before carrying out any internal inspection.
Before replacing the control panel, ensure that the power source has been applied to the unit for more than 48hrs.
Use the following instructions to check for any irregularities.
1. Isolate the mains power.
2. Remove the lower front heater panel to expose the electrical box.
3. Remove the four screws (one in each corner on the controller facia) and carefully lift the front face forward, taking care not to dislodge the wide ribbon cable.
4. Reinstate power to the unit. WARNING: 230V Mains Supply Present!
5. Ensure the black microchip is secure to the pcb and all legs are located correctly and not bent. Ensure notch on microchip is adjacent to ribbon catch plate. Check the display for correct operation.
6. Ensure the LED ribbon cable is secure in its catch plate and brown tab is locked. Check the display for correct operation.
7. *For a complete Hard Reset - push the power reset button on the rear of the pcb. Check the display for correct operation.
If the screen remains blank, a replacement pcb board will be required. Use Part MC200CAB/4