Vtcc : Variable Temperature And Capacity Control - Mitsubishi Heavy Industries KXZ Series Service Manual

(9) VTCC : Variable Temperature and capacity control (VRF inverter multi-system energy save control)
On the multi-system, target pressures are set uniformly so that indoor units operate with a constant capacity and repeat the ON/
OFF control with which thermostats are turned OFF when temperatures become near the setting temperature.
Owing to the tuning of target high/low pressure near the setting temperature, it becomes possible to perform the high efficiency
operation near the setting temperature.
For this reason, duration of time for highly efficient operation is increased by providing the compressor upper limit speed ac-
cording to the thermostat ON capacity.
・ Thermostat ON capacity ... Total capacity of indoor units which are operating with the thermostat ON.
(a) Correction of target high/low pressure
Starting condition (either of ① or ② )
(i)
① When the external input function assignment [P0] : Multi-system energy save control = Valid
② When -segment [P] (Multi-system energy save control I) = ON, if the external input function assignment [P0]
is not assigned this control.
(ii) Contents of control
① During the outdoor unit operation mode at cooling
・ Indoor load more than 50% → Corrected to the target cooling low pressure lower.
・ Indoor load less than 50% → Corrected to the target cooling low pressure higher.
② During the outdoor unit operation mode at heating
・ Indoor load more than 50% → Corrected to the target heating high pressure higher.
・ Indoor load less than 50% → Corrected to the target heating high pressure lower.
(Note) Indoor load condition (%) =
(Total capacity of indoor units of which load is high)
Total capacity of indoor units with the thermostat ON

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'14 • KX-SM-221