Panasonic CS-E24GKES / CU-E24GKE / CS-E28GKE / CU-E28GKE Service Manual ▷ View online
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13 Protection Control
13.1. Protection Control For All Operations
13.1.1.
Time Delay Safety Control
1. The compressor will not start for three minutes after stop of operation.
2. This control is not applicable if the power supply is cut off and on again or after 4-way valve deices condition.
2. This control is not applicable if the power supply is cut off and on again or after 4-way valve deices condition.
13.1.2.
30 Seconds Forced Operation
1. Once the compressor starts operation, it will not stop its operation for 30 seconds.
2. However, it can be stopped using remote control or Auto Switch at indoor unit.
2. However, it can be stopped using remote control or Auto Switch at indoor unit.
13.1.3.
Total Running Current Control
1. When the outdoor unit total running current (AC) exceeds X value, the frequency instructed for compressor operation will be
decreased.
2. If the running current does not exceed X value for five seconds, the frequency instructed will be increased.
3. However, if total outdoor unit running current exceeds Y value, compressor will be stopped immediately for 2 minutes.
4. The first 30 minutes of cooling operation, (A) will be applied.
13.1.4.
IPM (Power transistor) Prevention Control
A. Overheating Prevention Control
1. When the IPM temperature rises to 110
°C, compressor operation will stop immediately.
2. Compressor operation restarts after three minutes the temperature decreases to 95
°C.
B. DC Peak Current Control
1. When electric current to IPM exceeds set value of 30.0 ± 5.0 A, the compressor will stop operate. Then, operation will restart
after three minutes.
2. If the set value is exceeded again more than 30 seconds after the compressor starts, the operation will restart after two
minutes.
3. If the set value is exceeded again within 30 seconds after the compressor starts, the operation will restart after one minute. If
this condition repeats continuously for seven times, all indoor and outdoor relays will be cut off.
E24GK
E28GK
Operation Mode
X (A)
Y (A)
X (A)
Y (A)
Cooling/Soft Dry (A)
14.0
20.0
14.9
20.0
Cooling/Soft Dry (B)
12.0
20.0
14.6
20.0
Cooling/Soft Dry (C)
14.0
20.0
14.9
20.0
Heating
12.8
20.0
16.2
20.0
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13.1.5.
Compressor Overheating Prevention Control
Instructed frequency for compressor operation will be regulated by compressor top temperature. The changes of frequency are as
below figure.
below figure.
13.2. Protection Control For Cooling & Soft Dry Operation
13.2.1.
Outdoor Air Temperature Control
The compressor operating frequency is regulated in accordance to the outdoor air temperature as shown in the diagram below.
13.2.2.
Cooling Overload Control
i. Pipe temperature limitation/restriction
• Detects the Outdoor pipe temperature and carry out below restriction/limitation (Limit the compressor Operation frequency)
• The compressor stop if outdoor pipe temperature exceeds 65
• The compressor stop if outdoor pipe temperature exceeds 65
°C.
• If the compressor stops 4 times in 20 minutes, Timer LED blinking (F95: outdoor high pressure rise protection)
ii. Electrical part temperature rise protection control
• To prevent electrical component temperature rise during cooling overload.
• Judgement condition is by outdoor temperature (sampled every 10s).
• Judgement condition is by outdoor temperature (sampled every 10s).
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• Control contents:
Outdoor fan speed (switch to zone A and B minimum fan speed).
Outdoor total current (zone C) higher than the specified.
Outdoor total current (zone C) higher than the specified.
• Cancellation condition: When one of above is not satisfied.
13.2.3.
Freeze Prevention Control
1. When indoor heat exchanger temperature is lower than 2
°C continuously for six minutes, compressor will stop operating.
2. Compressor will resume its operation three minutes after the indoor heat exchanger is higher than 10
°C.
3. At the same time, indoor fan speed increase +40 rpm compared to its normal operation.
4. If indoor heat exchanger temperature is higher than 10
4. If indoor heat exchanger temperature is higher than 10
°C for five minutes, the fan speed will return to its normal operation.
13.3. Protection Control For Heating Operation
13.3.1.
Intake Air Temperature Control
Compressor will operate at rated freq. or less respectively if either one of the below conditions occur:
1. When the indoor intake air temperature is above 10
°C and remote control setting fan speed is lower Me-.
2. When the indoor intake air temperature is 30
°C or above.
13.3.2.
Outdoor Air Temperature Control
The compressor operating frequency is regulated in accordance to the outdoor air temperature as shown in the below figures. This
control will begin one minute after the compressor starts.
control will begin one minute after the compressor starts.
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13.3.3.
Overload Protection Control
The compressor operating frequency is regulated in accordance to indoor heat exchanger temperature as shown in below figures.
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