| The controller incorporates some diagnostic hardware and software to aid in troubleshooting problems. The display will flash the problem if detected when the heater in question is selected. |
| Problem |
Cause |
Solution |
| A. Display flashes “Opn” & “rEL” |
Open relay. Circuit inoperable. |
Replace Power Circuit Board.
|
| B. Display flashes “SHr” & “rEL” |
Shorted relay. Circuit inoperable. |
Replace Power Circuit Board. |
| Open heater. |
Test heater resistance. Replace heater. |
| Unplugged ribbon cable between Power and Main Circuit Boards. |
Verify ribbon cable connection.
|
| C. Display shows “LLL” |
Temperature is below 75° F (normal operation) |
N/A
|
| Display shows “LLL” for an extended period of time. |
Heater inoperable. |
Test heater resistance. Replace heater. |
| Probe inoperable. |
Check for open thermocouple wires from probe. Replace heater/probe assembly.
|
| Display shows “LLL” and then changes to “Opn”& “rel” and heater surface temperature is cool. |
Circuit inoperable. (see A). |
See A above.
|
| Display shows “LLL” and then changes to “SHr”&“rEL” and heater surface temperature is cool. |
Circuit inoperable. (see B) |
See B above.
|
| D. Display shows “HHH” for an extended period of time and heater surface temperature is hot. |
Temperature is above 400° F (abnormal operation) |
Diagnostic circuit inoperable. Replace Power Circuit Board.See B above.
|
| Display shows “HHH” for an extended period of time and heater surface temperature is cool. |
Probe is inoperable. |
Check for pinched thermocouple wires from probe. Replace heater/probe assembly.
|
