Fault: “E7 In-Line Heater UnderTemp.” What should I do?

Cause: This fault occurs when the temperature sensor in the in-line heater reports that the in-line heater is not reaching the required 110˚C within the 90 seconds allotted during an IDF water rinse. The fault message on the touchscreen display will indicate that the in-line heater is disabled. The operator will be able to select OK and continue the run, but the cause should be investigated later. 

The in-line heater operates during IDF water rinses to facilitate rinsing of the IDF bag and to ensure that solutions when deposited into the SDF bag are nominally at the same temperature as the pre-heated alcohol. The run-in progress will continue despite this fault. If known, note the temperature of the in-line heater when this fault occurred. 

Note: This fault can be falsely declared if the buffer or water are kept in a refrigerator. The buffer and water should be allowed to warm prior to the start of a routine. 
 
Result: Typically, the test results from this run would not be affected by the cooler water rinse temperatures. Be sure that the sample in the IDF bag was rinsed down into the filter area of the bag and observe the precipitation phase for SDF. If any anomalies are noted, pay particular attention to the test results as it is possible results for certain sample types may be more sensitive to lower temperatures during the precipitation phase than others. It may be advisable to repeat the run after the problem is corrected.  
 
Troubleshooting: After the assay with the fault is complete, turn the power off to the instrument and turn it back on to clear the fault. Test the in-line heater under Diagnostics / Heater Test. With a timer handy, observe how quickly the in-line heater heats up. Start the timer and immediately turn the in-line heater on and watch for it to get up to 70˚C.  It should reach 70˚C in 40-45 seconds. Turn it off as soon as 70˚C is reached. Confirm with an IR thermometer that the temperature reading on the touchscreen display matches the actual temperature of the in-line heater based on the reading taken with the IR thermometer. The two readings should be ± 5˚C of each other.    
 
Note: If the in-line heater temperature appears to be frozen at 8˚C, there is likely a problem with a disconnected thermistor wire at the MUX-T board or a lack of continuity in the thermistor wiring. 
 
If this fault is the result of a false low-temperature reading, or if you need any further assistance, contact ANKOM Technology at https://www.ankom.com/contact/technical-services or (315) 986-8090.  
 
For instructions, refer to the TDF Service Procedure In-Line Heater Replacement (TS018) linked below.