Bad thermistor - LG Heating & Cooling

The Ricoh copier error code SC551 / 551 is a fusing thermistor 1 error code.

It can mean:
1. The thermistor is not connected
2. The thermistor connector is bad

To reset this error try the code:
"Clear Mode"+107+"Clear/Stop" hold for 5s.
Turn ON and OFF the Main Switch.

If the problem persists you may need to contact a local service technician to take a look at your copier.

Even though the freezer thermistor passes the test, it's bad. The test only sees if the thermistor is open circuit or grounded. These thermistors can send bad information to board. Replace the freezer thermistor and I think that will solve your issue. Good Luck

Sounds like the thermistor may bad. But first, gain access to the back side of the refrigerator and see if there is an ammonia smell or a yellow residue on the back of the refrigerator. If either of those are present then the cooling unit has failed and must be replaced.
If that is not the case then there are several ways to test the thermistor.

1: Place the end of the thermistor that is located inside the refrigerator into a glass of slushy water and read the ohms resistance on the plug end which is located on the back of the refrigerator. Compare your readings to the chart. If they are not in range then the thermistor is bad and needs to be replaced.

2: Unplug the thermistor from the circuit board. It will be the harness that has only two wires going into a hard plastic plug. Leave it unplugged for 24 hours and check the temp inside the refrigerator. If the temp has dropped then the thermistor is bad and needs to be replaced.

To replace the thermistor remove the thermistor sensor end from the plastic clip. Remove the plastic grommet from the back wall of the refrigerator. Tape the new plug end to the sensor head of the old thermistor and gently guide it through the hole. Once the taped head/plug passes through the hole you may complete pulling the new thermistor through from the back side. Only pull enough to allow you to plug the new thermistor in. Un-tape the plug end from the head and plug the thermistor in to the circuit board. Reinstall the cover over the circuit board and reinstall the access pane. There will be some sealing putty on the old thermistor harness. Remove that and gently press it back into the hole around the new thermistor harness inside the refrigerator and reinstall the plastic grommet. Install the sensor end into the plastic clip and install the plastic clip between the first and second fins. The higher up on the fin the colder the temp will be inside the refrigerator.

Sounds like the thermistor is bad. Several ways to test.

1: Place the end of the thermistor that is located inside the refrigerator into a glass of slushy water and read the ohms resistance on the plug end which is located on the back of the refrigerator. Google the ohms resistance chart for Dometic thermistors and compare your readings to the chart. If they are not in range then the thermistor is bad and needs to be replaced.

2: Unplug the thermistor from the circuit board. It will be the harness that has only two wires going into a hard plastic plug. Leave it unplugged for 24 hours and check the temp inside the refrigerator. If the temp has dropped then the thermistor is bad and needs to be replaced.

To replace the thermistor remove the thermistor sensor end from the plastic clip. Remove the plastic grommet from the back wall of the refrigerator. Tape the new plug end to the sensor head of the old thermistor and gently guide it through the hole. Once the taped head/plug passes through the hole you may complete pulling the new thermistor through from the back side. Only pull enough to allow you to plug the new thermistor in. Un-tape the plug end from the head and plug the thermistor in to the circuit board. Reinstall the cover over the circuit board and reinstall the access pane. There will be some sealing putty on the old thermistor harness. Remove that and gently press it back into the hole around the new thermistor harness inside the refrigerator and reinstall the plastic grommet. Install the sensor end into the plastic clip and install the plastic clip between the first and second fins. The higher up on the fin the colder the temp will be inside the refrigerator.

Sounds like the thermistor is bad. Several ways to test.
1: Place the end of the thermistor that is located inside the refrigerator into a glass of slushy water and read the ohms resistance on the plug end which is located on the back of the refrigerator. Compare your readings to the chart. If they are not in range then the thermistor is bad and needs to be replaced.
2: Unplug the thermistor from the circuit board. It will be the harness that has only two wires going into a hard plastic plug. Leave it unplugged for 24 hours and check the temp inside the refrigerator. If the temp has dropped then the thermistor is bad and needs to be replaced.
To replace the thermistor remove the thermistor sensor end from the plastic clip. Remove the plastic grommet from the back wall of the refrigerator. Tape the new plug end to the sensor head of the old thermistor and gently guide it through the hole. Once the taped head/plug passes through the hole you may complete pulling the new thermistor through from the back side. Only pull enough to allow you to plug the new thermistor in. Un-tape the plug end from the head and plug the thermistor in to the circuit board. Reinstall the cover over the circuit board and reinstall the access pane. There will be some sealing putty on the old thermistor harness. Remove that and gently press it back into the hole around the new thermistor harness inside the refrigerator and reinstall the plastic grommet. Install the sensor end into the plastic clip and install the plastic clip between the first and second fins. The higher up on the fin the colder the temp will be inside the refrigerator.

That is a fuser fault. Can be caused by dirth thermistors on the hot or pressure rolls.
Can be a bad heat Rod. But on a 450, It is almost likely a bad thermistor. It is the flexable temperature sensor that rests on the hot roll to monitor the temperature.

Hi

Error F03 in Hotpoint washer means that the thermistor is open. When thermistor turns bad it will not let the water to heat or in some cases will boil the water to extreme temperatures. You’ll need to replace the thermistor to resolve this issue. The thermistor is located in the motor control unit. Inspect the element if its open circuit, it should read 1500-1800 ohms on Rx1 on the multimeter, if not then element is bad. To check/replace the element remove the lower rear panel. Hope this helps...

Daniel

Conversion Chart for 10k Thermistors

Here the reset procedure that is done through operation panel: press "Clear Modes" botton,then 107,then press and hold the "Stop" key for 3-5 seconds until you see the screen has changed.After that you need to turn the main power swith off and back on.The error code should be reset at this point.If it comes back,you may have a bad thermistor,bad fusing lamp or a bad connector.