Panasonic U-36LE1U6 Service Manual page 33

4. Mini VRF Alarm Codes
F16 alarm
Alarm code F16
Alarm meaning
High-pressure sensor trouble
Alarm conditions
The saturation temperature at the detected pressure is 10 °F (5 °C) or more below the highest
indoor-unit E1 temperature continuously for 30 minutes.
(1) High-pressure sensor malfunction
Probable cause
(2) Failure to connect the connector to the outdoor unit PCB
(3) Failure to open the service valve
(4) Clogged tubing
(5) Valve leakage
(6) Over-charging
(7) Outdoor unit PCB failure
(8) Electrical noise
(1) High-pressure sensor failure
Check
• Check for cut wiring.
• Connect a gauge to the high-pressure pressure outlet and check for changes in the value
displayed by the monitoring software, and for large deviation of the gauge pressure.
• During heating, check whether the temperature is lower than the highest indoor-unit E1
temperature.
* The pressure detected by the high-pressure sensor is the highest pressure in the system.
Therefore during heating the converted saturation temperature will never be lower than
any indoor-unit E1 temperature. During cooling this temperature will never be lower
than the outdoor unit liquid temperature.
(2) Failure to open the service valve, clogged tubing, valve leakage, over-charging.
In all of these cases, an alarm occurs when there are rapid pressure fluctuations and tracking
of the detected pressure is poor.
• Check the open/closed status of the valve.
• Check for valve leakage and over-charging
When valve leakage or over-charging occurs, refrigerant is likely to accumulate in the
outdoor units or indoor units, resulting in a sudden rise in pressure at start that occurs
before the refrigerant in the heat exchanger is discharged.
* The representative valve to check is a mechanical valve.
(3) Outdoor unit PCB failure
• The check items are the same as for a high-pressure sensor malfunction.
A normal PCB is needed to determine whether the problem is a PCB failure or a pressure
sensor malfunction. If an abnormality was found at the check items for a high-pressure
sensor malfunction, first try replacing the PCB and check again.
Trouble is corrected : Outdoorunit PCB failure
Trouble is not corrected : High-pressuresensor malfunction
Correction
(1) Replace the high-pressure sensor.
Caution: Because the high-pressure sensor connection incorporates a Schrader-type valve,
(2) Replace the PCB.
(3) Correct the locations of problems in the refrigeration cycle.
• Correct locations where clogging or leakage has occurred.
• In the case of over-charging, recover refrigerant. (Adjust the amount of refrigerant).
Example
This alarm may result when the service valve is closed or when valve leakage (particularly from
the mechanical valve) occurs.
it can be removed and replaced. However, the high-pressure sensor can be easily
damaged by high voltage; therefore use sufficient caution with regard to static
electricity.
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Trouble Diagnosis
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