Daiken VRV II HELP!

[jbomba]

To all the Daiken Gurus!

im working on on a vrv II system at the moment. I have a master outdoor unit & 2 slaves running off it. Every month or so I get a J3 error (Discharge thermistor malfunction) according to the service manual. Ive tested all discharge thermistors and all were reading acceptable values. The system has the correct charge in it aswell. What else could cause this problem?

[Brian_UK]

Have you tested the thermistors at a range of temperatures?

[VRVIII]

To all the Daiken Gurus!

im working on on a vrv II system at the moment. I have a master outdoor unit & 2 slaves running off it. Every month or so I get a J3 error (Discharge thermistor malfunction) according to the service manual. Ive tested all discharge thermistors and all were reading acceptable values. The system has the correct charge in it aswell. What else could cause this problem?

Hi,
If you use monitoring mode setting 14 for latest error info or 15 for previous error info you will be able to identify which module and which thermistor is causing the error. See previous post with details http://www.refrigeration-engineer.com/forums/showthread.php?t=22931
I would suggest replacing the thermistor as it may be out of calibration or moisture has got in side.

[wigs]

thermistor values should all be equal if they are all the same temperature and its worth testing them when the unit has been off for a while and when you are sure that they are all at the same temp. however i have found that the fault codes are often the equipments best guess and not always correct I had a J3 fault code and sometimes an L5 on a VRVII and found the inverter compressor was down.

Thermistors are a weak component and do often fail and are a reasonable cheap and simple replacement.

[VRVIII]

thermistor values should all be equal if they are all the same temperature and its worth testing them when the unit has been off for a while and when you are sure that they are all at the same temp. however i have found that the fault codes are often the equipments best guess and not always correct I had a J3 fault code and sometimes an L5 on a VRVII and found the inverter compressor was down.

Thermistors are a weak component and do often fail and are a reasonable cheap and simple replacement.
The discharge thermistor temp/resistance values are completely different when compared to the other thermistors, these will not be equal when at the same temperature. VRV discharge thermistors will have approx 10x the resistance value of all other outdoor unit thermisors.

J3 error is generated when the sensor resistance is >400Kohms or <3.5Kohms