Panasonic U-10MF1E8 Service Manual page 15

3. Compressor Control
(3) Increasing/decreasing the heat exchanger capacity (when the outdoor unit heat exchanger is functioning as an
evaporator)
• Primarily when both the evaporation temperature (Te) and condensation temperature (Tc) are low
This occurs when the cooling capacity (heat intake) is high and the heating capacity (heat discharge) is low.
The outdoor heat exchanger capacity is increased, increasing the system evaporation capacity and raising
the evaporation temperature (Te). The amount of heat intake at the outdoor unit heat exchanger increases,
increasing the heat discharge at the Heating mode indoor units and raising the condensation temperature (Tc).
• Primarily when both the evaporation temperature (Te) and condensation temperature (Tc) are high
This occurs when the cooling capacity (heat intake) is low and the heating capacity (heat discharge) is high.
The outdoor heat exchanger capacity is decreased, decreasing the system evaporation capacity and lowering
the evaporation temperature (Te). The amount of heat intake at the outdoor unit heat exchanger decreases,
decreasing the heat discharge at the Heating mode indoor units and lowering the condensation temperature (Tc).
Outdoor Heat Exchanger Control Table (when the outdoor heat exchanger is functioning as an evaporator)
A
B
C
3-6-4. Protection control
Protection control consists of 2 types of protection: air discharge temperature protection and current protection. The
limit values from this protection control are incorporated into the output compressor capacity increase/decrease
values that were calculated from control based on the temperature at the indoor unit heat exchanger (roadmap
control).
* In some cases, the control shown below may stop the compressor, issue a warning, or reduce the compressor
capacity.
(1) Air discharge temperature protection
During operation when only a single outdoor unit is installed, the air discharge temperature level is determined
(the highest value is used), and the compressor capacity is limited, by using the air discharge temperature of
the operating compressor (as shown in the tables below).
Air discharge temperature level: Highest level among the air discharge temperature levels of all compressors
Air discharge temp. level
The values shown in the table above are reduced to the values calculated by roadmap control.
Low Condensation Temp. [Tc]
A
STAY
UP
Discharge temp.
5 104
4 103
3 102
2 99~ Less than 102
1 97 ~ Less than 99
0 Less than 97
B C
DOWN
Target
STAY
STAY
STAY
UP
Horsepower limit
Decrease by 2 horsepower
Decrease by 1 horsepower
Decrease by 0.5 horsepower
Prohibit horsepower increase
Permit horsepower increase
No control
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3-WAY SYSTEM
Control Functions
High
D
STAY
STAY
1