Unit installation

OMRCPMICRO 61
ADI board
All digital and analog input signals are conditioned by the ADI Board. Power for the board is derived from the
Microprocessor Control Board via the interconnecting ribbon cables. If the ADI Board appears inoperative,
make sure these ribbon cables are fully seated in their sockets and the locking tabs are engaged.
The digital inputs indicate the presence of 24 VAC by illuminating its corresponding LED. At 7.5 VAC to 24
VAC the digital input contacts are considered closed and the LED will be on. Below 7.5 VAC the contacts are
considered open and the LED will be off. Individual digital inputs may be tested by momentarily installing a
jumper between terminal 25 and the ADI Board terminal to be tested. If the input is operating properly, the LED
will illuminate when 24 VAC from terminal 25 is applied. See Figure 17.
Temperature sensors receive operating power from the ADI Board which relies on the Microprocessor Control
Board's regulated 5 VDC power supply. If all temperature sensors appear to have failed, check the 5VDC
supply on the controller.
Troubleshooting the keypad/display board
Operating power for the keypad/display is provided by the MCB via the interconnecting ribbon cable. An
inoperative keypad/display can be caused by a loose or damaged ribbon cable or the loss of the controller's
power supply. The keypad/ display is also thermally sensitive.
Display is hard to read
The clarity of the LCD display can be affected by ambient temperature. Typically, less contrast will result with
cooler temperatures. If the display is difficult to read and adjusting the yellow contrast trim pot. If this has no
effect, it is likely that either the keypad/display or its ribbon cable is defective.
Display is blank or garbled
If the MCB appears to be functioning properly and the display is completely blank or garbled, perform the
following procedure:
1. Try cycling power to the controller by opening and then closing circuit breaker CB1 (see note).
2. Try adjusting the contrast trim pot, which is located on the back of the keypad/display assembly on the
left-hand corner. If the contrast trim pot has no effect, it is likely that either the keypad/display or its
ribbon cable is defective.
3. After removing power from the controller, check the ribbon cable and connections between the
keypad/display and the MCB. Look for bent pins. Restore power after reconnecting the ribbon cable.
4. Try swapping a known good ribbon cable and keypad/ display. These may come, for example, from a RMS
panel— the keypad/display is the same. Swap these components separately to isolate the problem.
Remove power from the controller before disconnecting the suspect component, and restore power after
connecting the replacement component. If the problem persists, it is likely that the MCB is defective.
Note: The keypad/display and MCB must be powered up together; otherwise, the display will be
blank. Therefore, if the keypad/ display is ever disconnected from the MCB and then reconnected,
power to the controller must be cycled to restore the display. Cycle power to the controller by
opening and then closing circuit breaker CB1.
Open or shorted temperature sensor circuits
The controller has built-in functions which will aid in the diagnosis of temperature sensor problems. The
controller will display either "open" or "short" instead of a temperature value on menus 4, 7 and 8 of the
keypad/display for monitor only and control sensors or display an alarm indicating "Bad Lvg WaterSen" for
the control sensor.
If the menus indicate a problem, check the sensor circuit wiring for shorts, disconnections or scrapes. If the
sensor circuit wiring and connections are intact, the sensor is probably defective. Verify this by performing
the following "Erroneous Temperature Readings Procedure".