Sanyo ECO-i 3-WAY MULTI SYSTEM Service Manual page 10

3. Compressor Control
3-3. Compressor Capacity Control
The compressor operating conditions vary depending on the indoor unit operating conditions and on the effects
of indoor heat load, outside temperature, and other factors. Unit No. 1 (CCU) calculates the required capacity
according to these operating conditions, and allocates the capacity requirement among the outdoor units,
according to the compressor start/stop rules. Fine adjustments to system capacity control are made by the inverter
compressors. (Depending on the conditions, all inverter compressors may be operating for fine adjustment.)
3-4. Inverter Compressor Capacity Control
(1) The inverter compressor has a center limit value and upper limit value for the operating frequency. These limits
are set for each outdoor unit capacity.
(2) The inverter frequency during operation may be lower than the frequency listed above due to overload current
protection control. In this case, the inverter frequency lower limit is 22 Hz.
* If Quiet mode is selected, the inverter may stabilize at a frequency lower than those stated above.
For information about Quiet mode, refer to the field application functions.
3-5. Forced Compressor Stop
After a compressor stops, it will not start for a period of 3 minutes (3 minutes forced OFF). However, this does not
apply when the compressor was forced to stop as the result of a control operation during the special controls (start
control, defrost control, refrigerant oil recovery control, etc.) which are described later.
3-6. Roadmap Control
(1) The below controls are performed according to the pressure sensor on the outdoor unit, and the 2 temperature
sensors attached to the indoor unit heat exchanger.
* With roadmap control, the pressure detected by the pressure sensor is converted to saturation temperature. A
temperature that has been converted to saturation temperature is called the pressure sensor temperature.
(2) These controls are performed every 30 seconds.
(3) The temperatures used to determine the area (A, AB, B, C) for the evaporation temperature control shown in
the figure on the next page, and for condensation temperature control, may vary depending on the relationships
among factors including the difference between the room temperature setting and the indoor unit air intake
temperature (= air intake temperature difference) and the difference between the air discharge temperature
setting and the air discharge temperature (= air discharge temperature difference).
(4) Definitions of evaporation temperature and condensation temperature
Evaporation temperature (Te):
Condensation temperature (Tc): Highest temperature among the outdoor unit pressure sensor temperature and
* E3 temperature is not used for condensation temperature detection, because it may indicate the temperature
of superheated gas.
Lowest heat exchanger temperature (E1, E3) at any indoor unit
the heat exchanger temperatures (E1) at all indoor units where the heating
thermostat is ON.
Ordinarily, this is the outdoor unit pressure sensor temperature. (If multiple
outdoor units are connected, this is the highest outdoor unit pressure sensor
temperature.)
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3-WAY ECO-i SYSTEM
Control Functions
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