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PX=125.6
°F
PX –0.1
Thermostat OFF
Horsepower increase
prohibited
Horsepower increase
permitted
Horsepower increase
permitted
Maximum requirement level [L]
* Depending on the maximum requirement level
of the indoor unit, the judgment temperatures
for each area may vary as shown in the figure
(example).
(1) For indoor units which are operating in Heating mode, if one unit is selected for a test run, the air intake tem-
perature difference is ignored, however Tc control is performed according to the figure above in order to pre-
vent excessive load. (This is used for test run checks, etc.)
(2) Even within the same area, the compressor capacity varies depending on the refrigerant temperature.
(3)
(4)
(1)
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
2
1
0
3
4
5
221
219
217
Discharge temp. °F
Horsepower limit
Less than 208
Decrease by 2 horsepower
Decrease by 1 horsepower
Decrease by 0.5 horsepower
No control
The values shown in the table above are reduced to the values calculated by roadmap control.
Condensation Temperature (Tc) Control:
Control of Indoor Units Operating either in Cooling Mode or Heating Mode
3-6-2.
118.5
118.4
116.6
116.4
113.0
112.8
Horsepower decrease
Area D
Area C
Area B
Area AB
Area A
118.4
116.6
3015
0
98.6
100.4
109.4
107.6
If the condensation temperature (Tc) enters area D and the thermostat turns OFF, the next time the compressor
starts it may restart from a lower capacity.
Temperature PX is the coefficient value used to correct for any deviation with the high pressure or condensa-
tion temperature. It may vary. (At the time of shipment it is 127°F.)
Protection control consists of 2 types of protection: 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 coil (roadmap control).
In some cases, the control shown below may stop the compressor, issue a warning, or reduce the compressor
capacity.
*
Discharge Temperature Protection
Air discharge temp. level
212 ~ Less than 217
208 ~ Less than 212
Permit horsepower increase (slowly)
3-6-3. Protection control
Prohibit horsepower increase
1 - 7
W-2WAY ECO-i SYSTEM
Control Functions
3. Compressor Control