Daikin Enfinity - Microtech III Unit Controller LED Faults and Remedy

troubleshooting
MicroTech III unit controller LED faults and remedy
Table 16: I/O expansion communication fail
Description Type Yellow Green Red
I/O Expansion Communication Fail Fault ON Flash Flash
• Verify connection of 12 wire cable between H5 on the main board and H1 on the I/O expansion board is fully engaged in the connector.
• Verify run program jumper on the I/O expansion board is installed in the run position.
• Replace the run jumper with a spare jumper.
• Replace I/O expansion board.
Table 17: Invalid configuration
Description Type Yellow Green Red
Invalid Conguration Fault Flash Flash OFF
• Verify jumper selection on both the main board and I/O expansion board. Jumper selections must be veried using the jumper conguration set-
ting outline in this manual.
Table 18: Low voltage brownout / emergency shutdown
Description* Type Yellow Green Red
Low Voltage Brownout Fault OFF Flash OFF
Emergency Shutdown Mode OFF Flash OFF
* Same LED display for both conditions
• Verify the E terminal is not connected to common. Remove wire, if connected, and LED should change to solid green only.
• Conrm the low voltage supply is between 19-32VAC at the H1 terminal of the main board. If the low voltage supply is out of range, verify the unit
supply voltage matches the nameplate voltage and the correct transformer primary wire has been selected.
Table 19: Compressor high pressure
Description Type Yellow Green Red
Compressor High Pressure Fault OFF OFF Flash
• Verify high pressure switch is connected to terminal H3 on the main board.
• Check for continuity of the high pressure switch.
If the high pressure fault resets when power is recycled:
• Check water ow (cooling operation)
• Check airow (heating operation)
• Entering water and air temperatures should be within the operating limits.
Table 20: Compressor low pressure
Description Type Yellow Green Red
Compressor Low Pressure Fault OFF OFF ON
• Loose wire connection on low pressure circuit
• Failed low pressure switch
• Unit is low on charge
Table 21: Compressor suction temp sensor fail, room temp sensor fail, leaving water temp sensor fail
Description Type Yellow Green Red
Compressor Suction Temp Sensor
Fail
Fault Flash Flash ON
Room Temp Sensor Fail (Room Sen-
sor Control Only)
Fault Flash Flash ON
Leaving Water Temp Sensor Fail Fault Flash Flash ON
• Check connection of low suction temperature sensor on terminal H6 pins 2 and 3.
• Check resistance of low suction temperature sensor, leaving water temperature sensor, and room sensor or return air sensor. All sensors are
10kohm thermistor @77°F.
• Return air sensor and room sensor shall not be connected simultaneously.
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