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2WAY VRF SYSTEM
Trouble Diagnosis
3. 2WAY Alarm Codes
F16 Alarm
Alarm code
F16
Alarm meaning
High pressure sensor of the outdoor unit has failure. (HPS)
Alarm conditions
•
High-pressure sensor disconnected or open circuit.
•
High-pressure sensor detected over 3.6MPa continuously for 30 minutes while outdoor units stopped.
•
High-pressure sensor detected over 3.6MPa while outdoor units were operating.
(In some cases, start and stop may sometimes repeat due to pre-trip mode.)
Probable cause
(1) High-pressure sensor failure
(2) Failure to connect the connector to the Outdoor Unit Control PCB
(3) Failure to open the service valve of the outdoor unit
(4) Clogged refrigerant circuit
(5) Refrigerant over-charging
(6) Outdoor Unit Control PCB failure
Check
(1) High-pressure sensor failure
•
Check the sensor resistance value. (Use a tester and measure the resistance between sensor No. 1
and No. 3)
Resistance of less than 10k
Ω
indicates a short circuit or other trouble.
Resistance of 10k
Ω
- 200k
Ω
is normal. Resistance of more than 200k
Ω
indicates an open circuit or
other trouble.
•
Connect a gauge to the high-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 connect the connector to the Outdoor Unit Control PCB
Check the connector connected to the Outdoor Unit Control PCB
(3) Failure to open the service valve
Check the open/closed status of the service valve.
(4) Check for clogging of the refrigerant circuit. (5) Check for refrigerant over-charging.
When clogging or over-charging occurs, refrigerant is likely to accumulate in the outdoor unit (cooling)
and indoor unit (heating). Sudden rise in pressure at start may sometimes occur.
(6) Outdoor Unit Control 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: Outdoor Unit Control PCB failure
Trouble is not corrected: High-pressure sensor malfunction
Correction
(1) Replacement of high-pressure sensor
When replacing a high-pressure sensor, carry out after refrigerant recovering of outdoor unit.
(2) Replacing the Outdoor Unit Control PCB
(3) Correct malfunction of refrigerant cycle.
•
Open valve of outdoor unit.
•
Correct clogging.
•
In the case of refrigerant over-charging, recover appropriate amount of refrigerant.
* Standards of over-charging
Install the pressure gauge at the high-pressure removal port of outdoor units and check for it.
During cooling: Not available in case of low outdoor temperature or adjusting the outdoor fan.
While both the 1st and 2nd compressors are operating under 12-step or 13-step in
the fan mode, high-pressure's saturation temperature indicates the outdoor air
tempe around 27°F (15°C).
If the temperature is 9°F (°5C) higher than the said temperature, over-charging might
be expected.
During heating: There is an indoor unit where refrigerant flow is poor (E1 temperature and discharge
temperature are low), and the mechanical valve of that unit is opened to 300 pulses
or more, and the E1 temperature is close to room temperature. However be aware
that this kind of data results often when there is a height difference between indoor
units. Reducing the amount of refrigerant will improve the refrigerant flow, however
reducing it too much will increase the likelihood of alarms related to low oil level
(scroll-side), the low-pressure sensor, and discharge temperature. Use caution.
Example
Malfunction had occurred when the liquid, suction and discharge tubes were clogged together.
SM830237-07_北米向け2WAY_VRF.indb 14
18/06/18 18:50:11