Kaisai KMK-60RY1, Service Manual

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M thermal Split
22 202004
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4 Normal Operation Control
4.1 Component Control during Normal Operation
Table 3-4.1: Component control during heating and domestic hot water operations
Component Wiring diagram label
6-16kW
Control functions and states
Inverter compressor
COMP
●
Controlled according to load requirement from hydronic system
DC fan motor FAN
●
Controlled according to outdoor heat exchanger pipe temperature
Electronic expansion
valve
EXV
●
Position (steps) from 0 (fully closed) to 480 (fully open), controlled according
to discharge temperature, suction superheat and compressor speed
Four-way valve 4-WAY
●
On
Table 3-4.2: Component control during cooling operation
Component Wiring diagram label 6-16kW Control functions and states
Inverter compressor
COMP
●
Controlled according to load requirement from hydronic system
DC fan motor FAN
●
Controlled according to outdoor heat exchanger pipe temperature
Electronic expansion
valve
EXV
●
Position (steps) from 0 (fully closed) to 480 (fully open), controlled according
to discharge temperature, suction superheat and compressor speed
Four-way valve 4-WAY
●
Off
4.2 Compressor Output Control
The compressor rotation speed is controlled according to the load requirement. Before compressor startup, the Split
outdoor unit determines the compressor target speed according to outdoor ambient temperature, leaving water set
temperature and actual leaving water temperature and then runs the appropriate compressor startup program. Refer to
Part 3, 3.2 “Compressor Startup Program”. Once the startup program is complete, the compressor runs at the target
rotation speed.
4.3 Compressor Step Control
The running speed of six-pole compressors in rotations per second (rps) is one third of the frequency (in Hz) of the
electrical input to the compressor motor. The frequency of the electrical input to the compressor motors can be altered at
a rate of 1Hz per second.
4.4 Four-way Valve Control
The four-way valve is used to change the direction of refrigerant flow through the water side heat exchanger in order to
switch between cooling and heating/DHW operations. Refer to Part 2, 3 “Refrigerant Flow Diagrams”. During heating and
DHW operations, the four-way valve is on; during cooling and defrosting operations, the four-way valve is off.
4.5 Electronic Expansion Valve Control
The position of the electronic expansion valve (EXV) is controlled in steps from 0 (fully closed) to 480 (fully open).

At power-on:

The EXV first closes fully, then moves to the standby position. After a few seconds the EXV moves to an initial
running position, which is determined according to operating mode and outdoor ambient temperature. After a
further a few minutes, the EXV is controlled according to suction superheat and discharge temperature. Once a
further a few minutes have elapsed, the EXV is then controlled according to suction superheat, discharge
temperature and compressor speed.

When the outdoor unit is in standby:

The EXV is at standby position.

When the outdoor unit stops:

The EXV first closes fully, then moves to the standby position.
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4.6 Outdoor Fan Control
The speed of the outdoor unit fan is adjusted in steps, as shown in Table 3-4.1.
Table 3-4.3: Component control during cooling operation
Fan speed index
Fan speed (rpm)
6/8/10kW 12/14kW
16kW
W1 200 200 200
W2 250 250 250
W3 300 300 300
W4 350 350 350
W5 400 400 400
W6 450 450 450
W7 500 500 500
W8 530 550 550
W9 550 580 600
W10 580 610 650
W11 600 630 700
W12 600 650 730
5 Protection Control
5.1 High Pressure Protection Control
This control protects the refrigerant system from abnormally high pressure and protects the compressor from transient
spikes in pressure.
Figure 3-5.1: High pressure protection control
Notes:
1. P
c
: Discharge pressure
When the discharge pressure rises above 4.3MPa the system displays P1 protection and the unit stops running. When the
discharge pressure drops below 3.6MPa, the compressor enters re-start control.
5.2 Low Pressure Protection Control
This control protects the refrigerant system from abnormally low pressure and protects the compressor from transient
drops in pressure.
Figure 3-5.2: Low pressure protection control
Notes:
1. P
e
: Suction pressure
P
c
> 4.3MPa P
c
< 3.6MPa
Normal operation
High pressure protection, error code P1 is displayed
P
e
< 0.14MPa
P
e
> 0.30MPa
Normal operation
Low pressure protection, error code P0 is displayed
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