Terminal Unit
Control (TUC)
Reading Diagnostics
Use the TUC human interface to read the current unit diagnostic. If no diagnostics are present, the last diagnostic appears.
Perform the following steps. Refer to Table 23 on page 72 for staging details.
1.Read and record the initial TUC address.
2.Set the TUC DIP switch #5 to ON (address = 8).
3.Short and hold the test input.
4.The LEDs will blink to define a diagnostic code. The diagnostic information will be displayed in a series of three blink sequences. Sequence 1: When the test input is shorted continuously,
all LEDs go off for one second.
Sequence 2: LED #5 will light to indicate that sequence 2 is currently being displayed. LEDs one through four will display the first part of the diagnostic code.
Sequence 3: LED #6 will light to indicate that sequence 3 is currently being displayed. LEDs one through four will display the second part of the diagnostic code.
5.Refer to Table 24 on page 74 to interpret the blink sequences’ corresponding diagnostic code.
6.Read and record the current diagnostic. Then return the DIP switches to the initial positions recorded in step 1. Short the test inputs to set the address in the TUC EEPROM.
Example: Diagnostic blink sequences for condensate overflow (8B)
Sequence 1 |
| Sequence 2 |
| Sequence 3 |
| ||||||
1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 |
ϒ ϒ ϒ ϒ λ ϒ ϒ ϒ λ ϒ λ λ | |||||||||||
ϒ ϒ |
| ϒ | λ ϒ |
| ϒ | ϒ λ |
| ϒ | |||
5 | 6 |
| 7 | 5 | 6 |
| 7 | 5 | 6 |
| 7 |
101 |
