Panasonic CS-VE9NKE Service Manual page 66

H98 Indoor unit
overpressure
protection
H99 Indoor unit heat
exchanger freezing
protection
F11 Cooling-Heating
switching error
F16 Cooling-Dry switching
error
F19 Heat storage cycle
error
F90 PFC protection
F91 Refrigeration cycle
error
When the temperature of the indoor unit heat exchanger temperature sensor exceeds
60°C during the heating operation, this diagnosis code is stored in the memory and the
compressor stops operation. It resumes operation after 180 seconds if the temperature
is below 60°C. No error code is displayed.
<Points of diagnosis>
1. Check of the indoor unit heat exchanger temperature sensor (Check for change in
characteristic and resistance value): Symptom – No hot start, no thermo ON and
repeating stop and start during the start of the operation.
2. Additional check for short-circuit of the indoor unit and clogging of air filter.
When the temperature of the indoor unit heat exchanger temperature sensor is 0°C for 6
consecutive minutes during the cooling or dry operation, this diagnosis code is stored in
the memory and the compressor stops. It resumes operation after 180 seconds if the
temperature is 10°C and above. No error code is displayed.
<Points of diagnosis>
1. The primary cause is cooling or dry operation at low outside temperature. This is not
a failure. H99 is also displayed if dry operation is performed under AUTO mode in
winter while the outside temperature goes up.
2. Check of refrigerant cycle: Gas leak (refrigerant level is low) and pipe breakage.
3. Additional check for short-circuit of the indoor unit and clogging of air filter.
When the temperature of the indoor unit heat exchanger temperature sensor after 4
minutes from the start of compressor is 45°C and above during cooling or dry cool
operation or below 0°C during heating operation, this diagnosis code is stored in the
memory and the compressor stops. It resumes operation after 180 seconds. The error
code is displayed if this error is detected four times within 40 minutes.
<Points of diagnosis>
1. Check of the 4-way valve: Check for disconnection or short-circuit of the 4-way valve
coil.
2. If the 4-way valve is normal, then switching error of the 4-way valve has occurred.
When the temperature of the heat exchanger temperature sensor after 3.5 minutes from
the start of compressor is below -7°C consecutively for 1 minute during cooling or dry
cool operation, this diagnosis code is stored in the memory and the air conditioner stops
operation. It resumes operation after 180 seconds. The error code is displayed if this
error is detected eight times within 75 minutes.
<Points of diagnosis>
1. Check of the 2-way valve: Make sure that no power is supplied during cool and dry
cool operation and the power is supplied during dry operation. Check for
disconnection of the coil (coil open).
2. If the coil is normal, then switching error of the 2-way valve has occurred.
If all of the following conditions are met three consecutive times, the power relay is OFF
for 2 minutes. Subsequently, if all of the following conditions are once again met three
consecutive times after the power relay is ON again, the TIMER indicator flashes. (The
air conditioner continues the operation.)
 The temperature of the heat storage tank is 45°C and above at the start of Non-Stop
De-Icing.
 The temperature of the heat storage tank drops by not more than 2°C after 4 minutes
from the start of Non-Stop De-Icing.
 The temperature of the outdoor unit pipe does not reach 6°C at the end of Non-Stop
De-Icing.
<Points of diagnosis>
1. Liquid leak from the heat storage tank.
2. Check if the 2-way valve of the heat storage tank is working.
The compressor stops if the DC voltage of the outdoor unit control board (PFC output)
exceeds the preset value for protection against over-voltage. The error code is
displayed if the protection is activated four times within 20 minutes.
<Points of diagnosis>
1. Check of the inverter circuit on the control board:
The voltage of IPM is checked within 3 minutes after the power is OFF and then ON.
Symptom: The compressor stops after 30 seconds from its start and F90 is stored in
the memory. The error code is displayed once the compressor is restarted four
times.
While the air conditioner is in operation beyond the ratings, this diagnosis code is stored
in the memory and the compressor stops if:
 During cooling or dry cool operation:
Indoor unit intake air temperature - Indoor unit pipe temperature < 4°C
 During heating operation:
Indoor unit pipe temperature - Indoor unit intake air temperature < 5°C
In the case where the air conditioner operates within the total current range of 0.7 –
1.4A for 5 minutes.
The compressor resumes operation after 180 seconds. The error code is displayed if
this error is detected two times within 20 minutes.
<Points of diagnosis>
1. Check of refrigerating cycle: Gas leak. (Gas level is less than a half.) The diagnosis
code to be displayed due to gas leak changes in the order of H99 → F97 → F91 →
H16 depending on the amount of gas leaked. The range of this error (F91) is
extremely small. (Protection of the compressor at the beginning of a season)
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 Dirt on air filter
 Short-circuit of
indoor unit
 Low refrigerant
level (relatively
low)
 Dirt on air filter
 Short-circuit of
indoor unit
 4-way valve
 4-way valve coil
 Heat exchanger
temperature sensor
(Bad connection /
detached
connector)
 2-way valve
 2-way valve coil
 Draining of the
antifreeze liquid
within the heat
storage tank
 Error of heat
storage tank 2-way
valve
 Outdoor unit control
board
 Draining of
refrigerant
(3-way valve
opening failure,
gas leak, etc.)