Midea Aqua Tempo Super II, MC-SU60-RN1L, MC-SU30-RN1L Service Manual
Commercial Air Conditioners
Service
Manual
Aqua Tempo Super II
CONTENTS
CONTENTS
Part 1 General Information ............................................................................ 3
Part 2 Component Layout and Refrigerant Circuits ..................................... 5
Part 3 Control ............................................................................................... 15
Part 4 Diagnosis and Troubleshooting ......................................................... 33
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Aqua Tempo Super II
Midea Aqua Tempo Super II
Manual
2 201709
Aqua Tempo Super II
Part 1
- General Information
Part 1
General Information
1 Unit Capacities and External Appearance ................................................... 4
2 Water outlet temperature range ................................................................ 4
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Midea Aqua Tempo Super II Service Manual
Table 1-2.1: Aqua Tempo Super II unit capacity range and unit appearances
Capacity
30kW
60kW
Model
MC-SU30-RN1L
MC-SU30-RN1L
Appearance
Power supply
380-415V/3Ph/50Hz
Table 1-2.1: Aqua Tempo Super II unit water outlet temperature range
Mode
Range
Cooling
Normal
5-20°C
Low water outlet
0-20°C
Heating
Normal
25-55°C
Note:
1. Use dial switch S5_1 on the main PCB to select the water outlet temperature range.
1 Unit Capacities and External Appearance
2 Water outlet temperature range
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Refrigerant Ci rcuits
Part 2
Component Layout and
Refrigerant Circuits
1 Layout of Functional Components ........................................................... 6
2 Piping Diagrams ..................................................................................... 10
3 Refrigerant Flow Diagrams ..................................................................... 13
Part 2 - Component Layout and
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Safety
valve
1 Layout of Functional Components
MC-SU30-RN1L
Figure 2-1.1: MC-SU30-RN1L front view
Wired
controller
DC inverter
compressor
Fan motor
Electric
control box
Accumulator
Figure 2-1.2: MC-SU30-RN1L rear view
Manual air
purge valve
Water inlet pipe
Oil separator
Water side heat exchanger
Manual water
drain valve
Water outlet
pipe
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Water flow switch
Refrigerant Ci rcuits
Figure 2-1.3: MC-SU30-RN1L top view
expansion valve
Aqua Tempo Super II
Part 2 - Component Layout and
Low pressure
switch
Solenoid valve
SV4
Discharge
temperature
switch
Low pressure
gauge point
Accumulator
High pressure
sensor
High pressure
switch
Four-way valve
Electronic
High pressure
gauge point
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control box
MC-SU60-RN1L
Figure 2-1.4: MC-SU60-RN1L front view
DC inverter
compressor
Fan motor
Electric
Oil separator
Figure 2-1.5: MC-SU60-RN1L rear view
Safety valve
Air purge valve
Water inlet pipe
Manual water
drain valve
Water outlet
pipe
Accumulator
Water side
heat exchanger
Accumulator
Water flow
switch
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Refrigerant Ci rcuits
Figure 2-1.6: MC-SU60-RN1L top view
expansion valve
Aqua Tempo Super II
Part 2 - Component Layout and
Low pressure
switch
High pressure
Solenoid
valve SV4
Discharge
temperature
switch
Low pressure
gauge point
High pressure
gauge point
sensor
High pressure
switch
Four-way valve
Electronic
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6
2 Piping Diagrams
MC-SU30-RN1L
Figure 2- 2.1: MC-SU30-RN1L pipi ng diagram
Tz/7
T3
T4
EXV
11
Twi
4
ST1
9
7
3
TP2
TP1
1
Legend
10 Water flow switch Tw Combined water outlet temperature sensor
11 Filter Th Air suction temperature sensor
EXV Electronic expansion valve SV4 Oil return solenoid valve
ST1 4-way valve
5
Taf2 Tw
Taf1
2
1 Compressor Tp1 Discharge temperature sensor 1
2 Low pressure switch Tp2 Discharge temperature sensor 2
3 Discharge temperature control switch T3 Air side heat exchanger refrigerant outlet
4 High pressu re switch T4 Outdoor ambient temperature sensor
5 Oil separator TZ/7 Air side heat exchanger refrigerant total outlet
6 Air side heat excha nger Taf1 Water side heat exchanger anti-freezing
7 Pressure sensor Taf2 Water side heat exchanger anti-freezing
8 Accumulator Twi Water side heat exchanger water inlet temperature
9 Water side heat exchanger Two Water side heat exchanger water outlet
Th
SV4
8
temperature sensor
temperature sensor
temperature sensor 1
temperature sensor 2
sensor
temperature sensor
Two
10
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Refrigerant Ci rcuits
MC-SU60-RN1L
6
Figure 2- 2.2: MC-SU60-RN1L pipi ng diagram
T3
T4
Capillary
Tz
EXV
11
Aqua Tempo Super II
Twi
3
Tp1
1.1
4
ST1
Taf2
Taf1
9
Two
5
Tp2
1.2
SV4
Legend
1 Compressor Tp1 Discharge temperature sensor 1
2 Low pressure switch Tp2 Discharge temperature sensor 2
3 Discharge temperature control switch T3 Air side heat exchanger refrigerant outlet
4 High pressure switch T4 Outdoor ambient temperature sensor
5 Oil separator TZ/7 Air side heat exchanger refrigerant total outlet
6 Ai r side heat exchanger Taf1 Water side heat exchanger anti-freezing
7 Pressure sensor Taf2 Water side heat exchanger anti-freezing
8 Accumulator Twi Water side heat exchanger water inlet temperature
9 Water side heat exchanger Two Water side heat exchanger water outlet
10 Water flow switch Tw Combined water outlet temperature sensor
11 Filter Th Air suction temperature sensor
EXV Electronic expansion valve SV4 Oil return solenoid valve
ST1 4-way valve
7
Th
8
temperature sensor
temperature sensor
temperature sensor 1
temperature sensor 2
sensor
temperature sensor
10
Tw
Part 2 - Component Layout and
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Key components:
1. Compressor
Maintains pressure differential between high and low pressure sides of the refrigerant system.
2. Fan
Ventilates the air side heat exchanger.
3. Oil separato r:
Separates oil from gas refrigerant pumped out of the compressor and quickly returns it to the compressor. Separation
efficiency is up to 99%.
4. Accumulator:
Stores liquid refrigerant and oil to protect the compressor from liquid hammering.
5. Electronic expansion valve (EXV):
Controls refrigerant flow and reduces refrigerant pressure.
6. Four-way valve:
Controls refrigerant flow direction. Closed in cooling mode and open in heating mode. When closed, the air side heat
exchanger functions as a condenser and water side heat exchanger functions as an evaporator; when open, the air
side heat exchanger functions as an evaporator and water side heat exchanger function as a condenser.
7. High and low pressure switches:
Regulate refrigerant system pressure. When the refrigerant system pressure rises above the upper limit or falls below
the lower limit, the high or low pressure switches turn off, stopping the compressor.
8. Discharge temperature switch:
Protects the compressor from abnormally high temperatures and transient spikes in temperature.
9. Air purge valve:
Automatically removes air from the water circuit.
10.Safety valve
Prevents excessive water pressure by opening at 43.5psi (3bar) and discharging water from the water circuit.
11.Water flow switch:
Detects water flow rate to protect the compressor and wat er pump in the event of insu fficient water flow.
12.Water pump:
Circulates water in the water circuit.
13.Pressure se n so r
Measures refrigerant system pressure.
14.Crankcase heater
Prevents refrigerant from mixing with compressor oil when the compressors are stopped.
15.Water side heat exchanger e lectric heater
Protects the water side heat exchanger from ice formation.
16.Water flow switch electric heater:
Provides additional heating when heating capacity provided by the heat pump is insufficient due to low ambient
temperatures, it also protects external water pipes from freezing.
17.Solenoid valve SV4
Returns oil to the compressor. It opens after 17 minut es of com pressor operation, closes after 3 minut es, t hen opens
again for 3 minutes at 17 minute increments.
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Refrigerant Ci rcuits
3 Refrigerant Flow Diagrams
Heating operation
Figure 2-3.1: Refrigerant flow during heating operation
Aqua Tempo Super II
Part 2 - Component Layout and
Cooling and defrosting operation
Figure 2-3.2: Refrigerant flow during cooling and defrosting o perations
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Part 3
- Control
Part 3
Control
1 General Control Scheme Flowchart ..................................................... 16
2 Stop Operation .................................................................................... 17
3 Standby Control .................................................................................. 17
4 Startup Control .................................................................................... 18
5 Normal Operation Control ................................................................... 20
6 Protection Control ............................................................................... 23
7 Special Control .................................................................................... 29
8 Role of Temperature Sensors in Control Functions ............................... 31
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S5_4 on main
PCB set to ON
Conditions met
for defrosting
Thermo on
Special control
Outdoor unit duty cycling
Additional control
Defrosting operation
7
Stop operation
System stops
2
Standby control
Water pump control
3
Startup control
Startup control for cooling operation
4
Thermo on
Normal operation control
Outdoor fan control
5
Protection control
Water side heat exchanger temperature difference protection control
6
1 General Control Scheme Flowchart
Sections 3-2 to 3-7 on the following pages detail when each of the controls in the flowchart below is activated.
Abnormal shutdown
Crankcase heater control
Compressor startup delay control
Compressor startup program
Startup control for heating operation
Component control during normal operation
Compressor output control
Compressor step control
Water pump select control
Four-way valve control
Electronic expansion valve control
High pressure protection control
Low pressure protection control
Discharge temperature protection control
Compressor and inverter module protection control
Voltage protection control
DC fan motor protection control
Water side heat exchanger anti-freeze protection control
Air side heat exchanger high temperature protection control
Note:
1. Numbers in the top right-hand corners of boxes indicate the relevant section of text on the following pages.
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Figure 3-3.1: Crankcase heater controlled according to outdoor ambient temperature
Figure 3-3.2: Crankcase heater controlled according to discharge temperature
Notes:
1. Tp1: discharge temperature sensor 1, Tp2: discharge temperature sensor 2.
Ambient temperature < 35 oC
Ambient temperature > 40 oC
Crankcase heater off
Crankcase heater is controlled according to discharge temperature
Max (Tp1, Tp2) < 40 oC
Max (Tp1, Tp2) > 50 oC
Crankcase heater off
Crankcase heater on
2 Stop Operation
The stop operation occurs for one of the following reasons:
1. Abnormal shutdown: in order to protect the compressors, if an abnormal state occurs the system makes a 'stop with
thermo off’ operation and an error code is displayed on the outdoor unit’s PCB digital displays and on the user
interface.
2. The system stops when the set temperature has been reached.
3 Standby Control
3.1 Crankcase Heater Control
The crankcase heater is used to prevent refrigerant from mixing with compressor oil when the compressors are stopped.
The crankcase heater is controlled according to the outdoor ambient temperature and discharge temperature. When the
outdoor ambient temperature is above 40°C, the crankcase heater is off; when the outdoor ambient temperature is below
35°C, the crankcase heater is controlled according to discharge temperature. Refer to Figures 3-3.1 and 3-3.2.
3.2 Water Pump Control
When the outdoor unit is in standby, the circulator pumps run continuously。
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Figure 3-4.1: Compressor startup program1 when ambient temperature is above 10°C
Notes:
1. Once the first, 60-second stage of the program is complete, the program proceeds to the subsequent stages in a
step-by-step fashion and exits when the target rotation speed has been reached.
Figure 3-4.2: Compressor startup program1 when ambient temperature is at or below 10°C
Notes:
1. Once the first, 90-second stage of the program is complete, the program proceeds to the subsequent stages in a
step-by-step fashion and exits when the target rotation speed has been reached.
42rps
60S
56rps
34rps
66rps
76rps
80rps
90rps
90S
90S
90S
90S
180S
60S
180S
100rps
Target rotation speed
Compressor
rotation speed (rps)
Time (s)
105rps
300S
42rps
90S
28rps
120S
34rps
60S
42rps
90S
56rps
60S
76rps
60S
66rps
60S
80rps
90S
90rps
180S
100rps
180S
Target rotation speed
Compressor
rotation speed (rps)
Time (s)
105rps
300S
4 Startup Control
4.1 Compressor Startup Delay Control
In initial startup control and restart control (except in defrosting operation), compressor startup is delayed such that a
minimum 7 minutes has elapsed since the compressor stopped, in order to prevent frequency compressor on/off and to
equalize the pressure within the refrigerant system.
4.2 Compressor Startup Program
In initial startup control and in re-start control, compressor startup is controlled according to outdoor ambient
temperature and discharge temperature. Compressor startup follows one of two startup programs until the target rotation
speed is reached. Refer to Figures 3-4.1, 3-4.2.
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Component
Wiring diagram
label
30kW
60kW
Control functions and states
Inverter compressor A
COMP A
●
●
Compressor startup program selected according to
ambient temperature and discharge temperature1
Inverter compressor B
COMP B
●
DC fan motor A
FAN A
●
●
Controlled according to ambient temperature
DC fan motor B
FAN B
●
Electronic expansion valve
EXV 1
●
●
Position (steps) from 0 (fully closed) to 480 (fully
open), controlled according to outdoor ambient
temperature, unit capacity.
Four-way valve
STF1
●
●
On after the compressor startup for 10s
Solenoid valve (oil balance)
SV4_1
●
●
Closed for 200s, open for 600s, then closed
Water pump1
PUPM1
●
●
On
Water pump2
PUPM2
●
●
Water side heat exchanger heater 1
EVA-HEAT 1
●
●
According to water side heat exchanger
anti-freezing temperature (Taf)
Water side heat exchanger heater 2
EVA-HEAT 2
●
Water flow switch heater
W-HEAT1
●
●
Controlled according to ambient temperature, water
inlet temperature and water outlet temperature
Electric auxiliary heater
E-HEAT_L/
E-HEAT_N
●
●
Controlled according to ambient temperature and
total water outlet temperature after the compressor
is on
Crank case heater 1
HEAT1
●
●
Controlled according to ambient temperature and
discharge temperature
Crank case heater 2
HEAT2
●
Notes:
1. Refer to Figure 3-4.1, Figure 3-4.2 and in Part 3, 4.2 “Compressor Startup Program”.
Component
Wiring diagram
label
30kW
60kW
Control functions and states
Inverter compressor A
COMP A
●
●
Compressor startup program selected according to
ambient temperature and discharge temperature1
Inverter compressor B
COMP B
●
DC fan motor A
FAN A
●
Controlled according to air side heat exchanger
refrigerant total outlet temperature (Tz/7)
DC fan motor B
FAN B
●
Electronic expansion valve
EXV 1
●
●
Position (steps) from 0 (fully closed) to 480 (fully
open), controlled according to outdoor ambient
temperature, outdoor unit initial frequency
Four-way valve
STF1
●
●
Off
Solenoid valve (oil balance)
SV4_1
●
●
Closed for 200s, open for 600s, then closed
Water pump1
PUPM1
●
●
On
Water pump2
PUPM2
Water side heat exchanger heater 1
EVA-HEAT 1
●
●
According to water side heat exchanger
anti-freezing temperature (Taf)
Water side heat exchanger heater 2
EVA-HEAT 2
●
Water flow switch heater
W-HEAT1
●
●
Controlled according to ambient temperature, water
inlet temperature and water outlet temperature
Electric auxiliary heat
E-HEAT_L/
E-HEAT_N
●
●
Off
Crank case heater 1
Heat 1
●
●
Controlled according to ambient temperature and
discharge temperature
Crank case heater 2
Heat 2
●
Notes:
1. Refer to Figure 3-4.1, Figure 3-4.2 and in Part 3, 4.2 “Compressor Startup Program”.
4.3 Startup Control for Heating Operation
Table 3-4.1: Component control during startup in heating mode
4.4 Startup Control for Cooling Operation
Table 3-4.2: Component control during startup in cooling mode
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Component
Wiring diagram
label
30kW
60kW
Control functions and states
Inverter compressor A
COMP A
●
●
Controlled according to load requirement
Inverter compressor B
COMP B
●
DC fan motor A
FAN A
●
●
Controlled according to air side heat exchanger pipe
temperature and discharge pressure
DC fan motor B
FAN B
●
Electronic expansion valve
EXV 1
●
●
Position (steps) from 0 (fully closed) to 480 (fully
open), controlled according to discharge superheat
and compressor frequency, and use suction
temperature, air side heater exchanger temperature,
discharge temperature to modify the control.
Four-way valve
STF1
●
●
On
Solenoid valve (oil balance)
SV4_1
●
●
Open regularly
Water pump1
PUPM1
●
●
On
Water pump2
PUPM2
●
●
Water side heat exchanger heater 1
EVA-HEAT 1
●
●
Off
Water side heat exchanger heater 2
EVA-HEAT 1
●
Water flow switch heater
W-HEAT1
●
●
Off
Electric auxiliary heater
E-HEAT_L/
E-HEAT_N
●
●
Controlled according to ambient temperature
Crank case heater 1
HEAT1
●
●
Off
Crank case heater 2
HEAT2
●
Component
Wiring diagram
label
30kW
60kW
Control functions and states
Inverter compressor A
COMP A
●
●
Controlled according to load requirement
Inverter compressor B
COMP B
●
DC fan motor A
FAN A
●
●
Controlled according to air side heat exchanger
refrigerant total outlet temperature (Tz/7)
DC fan motor B
FAN B
●
Electronic expansion valve
EXV 1
●
●
Position (steps) from 0 (fully closed) to 480 (fully
open), controlled according to suction superheat,
water inlet temperature and compressor frequency.
Four-way valve
STF1
●
●
Off
Solenoid valve (oil balance)
SV4_1
●
●
Open regularly
Water pump1
PUPM1
●
●
On
Water pump2
PUPM2
●
●
Water side heat exchanger heater 1
EVA-HEAT 1
●
●
According to water side heat exchanger
anti-freezing temperature (Taf)
Water side heat exchanger heater 2
EVA-HEAT 2
●
Water flow switch heater
W-HEAT1
●
●
Off
Electric auxiliary heater
E-HEAT_L/
E-HEAT_N
●
●
Off
Crank case heater 1
HEAT1
●
●
Off
Crank case heater 2
HEAT2
●
5 Normal Operation Control
5.1 Component Control during Normal Operation
Table 3-5.1: Component control during heating operation
Table 3-5.2: Component control during cooling operation
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5.2 Compressor Output Control
The compressor rotation speed is controlled according to the load requirement. Before compressor startup, the outdoor
unit determines the compressor target speed according to outdoor ambient temperature, discharge temperature and then
runs the appropriate compressor startup program. Refer to Part 3, 4.2 “Compressor Startup Program”. Once the startup
program is complete, the compressor runs at the target rotation speed.
The compressor speed is controlled according to two parts in normal operation:
In cooling mode: In a single system, the compressor speed is controlled according to the water outlet temperature and
water outlet setting temperature. In a combination system, the compressor of master unit is controlled according total
water outlet temperature and water outlet setting temperature, the compressor of the slave unit is controlled according to
water inlet and water outlet temperature. Both in a single system and combination system, the compressor speed is
limited by the inverter module temperature (Tf), ambient temperature, discharge temperature and air side heat exchanger
refrigerant total outlet temperature (Tz/7).
In heating mode: In a single system, the compressor speed is controlled according to the water outlet temperature and
water outlet setting temperature. In a combination system, all compressors are controlled according to the total water
outlet temperature and the water outlet setting temperature. Both in a single system and combination system, the
compressor speed is limited by inverter module temperature (Tf), ambient temperature, discharge temperature, discharge
pressure.
5.3 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 in two seconds.
5.4 Water pump select control
When the dial switch S5_3 on the main PCB is switched ON, the system runs “one small pump per unit” mode, when S5_3
is switched OFF, the system run “one large pump controlled by master unit” mode.
One pump control: only the master unit output pump signal, no pump signal output on the slave units.
Multiple pump control: output pump signal on all units.
S5_3 in one system must be switched to the same position or not error code FP will be displayed.
5.5 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 operations. Refer to Figures 2-3.1 and 2-3.2 in Part 2, 3 “Refrigerant Flow Diagrams”.
During heating operation, the four-way valve is on; during cooling and defrosting operation, the four-way valve is off.
5.6 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 (352 (steps)). After 30seconds the EXV moves to an
initial running position, which is determined according to the operating mode and outdoor ambient temperature.
When the unit operate in cooling mode, after 60 seconds, the EXV is controlled according to suction superheat, water
inlet temperature and compressor frequency.
When the unit operates in heating mode, after a further 60 seconds, the EXV is controlled according to discharge
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Table 3-5.3: Outdoor fan speed steps
Fan speed index
Fan speed (rpm)
30kW
60kW
FAN A
FAN A
FAN B 0 0 0 0 1 150
150
0 2 200
200
0 3 250
250
0 4 300
300
250 5 360
360
300 6 430
430
360 7 480
530
460
8 (super silent mode)
530
650
580 9 650
760
680
10(silent mode)
710
850
800
11
800
900
850
12(standard ESP mode)
820
950
900
Abbreviations:
ESP: External static pressure
superheat and compressor frequency, and uses the suction temperature, air side heater exchanger temperature,
discharge temperature to modify the control.
When the outdoor unit is in standby:
The EXV is at position 352 (steps).
When the outdoor unit stops:
The EXV first closes fully, then moves to the standby position (352 (steps)).
5.7 Outdoor Fan Control
The speed of the outdoor unit fan(s) is adjusted in steps, as shown in Table 3-5.3.
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Figure 3-6.1: High pressure protection control
Notes:
1. P
c
: Discharge pressure
Figure 3-6.2: Low pressure protection control
Notes:
1. P
e
: Suction pressure
Figure 3-6.3: High discharge temperature protection control
When P1 protection occurs 5 times
in 120 minutes, ta manual system
restart is required before the system
can resume operation.
Pc > 4.4MPa
Pc < 3.2MPa
Normal operation
Low pressure protection, error code P0 is displayed
When P0 protection occurs 5 times
in 120 minutes, a manual system
restart is required before the system
can resume operation.
Pe < 0.14MPa
Pe > 0.3MPa
Normal operation
Low pressure protection, error code P1 is displayed
Discharge temperature > 110°C
Discharge temperature < 100°C
Normal operation
High discharge temperature protection, error code P0 is
When P0 protection occurs 5 times
in 120 minutes, ta manual system
restart is required before the system
can resume operation.
6 Protection Control
6.1 High Pressure Protection Control
This control protects the refrigerant system from abnormally high pressure and protects the compressor from transient
spikes in pressure.
When the discharge pressure rises above 4.4MPa the system displays P0 protection and all units stop running. When the
discharge pressure drops below 3.2MPa, the compressor enters re-start control.
6.2 Low Pressure Protection Control
This control protects the refrigerant system from abnormally low pressure and protects the compressor from transient
drops in pressure.
When the suction pressure drops below 0.14MPa the system displays P0 protection and all the units stop running. When
the suction pressure rises above 0.3MPa, the compressor enters re-start control.
6.3 Discharge Temperature Protection Control
This control protects the compressor from abnormally high temperatures and transient spikes in temperature.
When the discharge temperature rises above 110°C the system displays P0 protection and all the units stop running. When
the discharge temperature drops below 100°C , the compressor enters re-start control.
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Figure 3-6.4: Compressor current protection control
Notes:
1. P4 is the protection for the power supply phase B, P5 is the protection for the power supply phase C.
Figure 3-6.5: Inverter module temperature protection control
Notes:
1. Tf1:Heat sink temperature 1; Tf2:Heat sink temperature 2
Figure 3-6.6: Compressor voltage protection control
Current > 25A
Current < 25A
Normal operation
Compressor current protection, error code P4 or P5 is displayed
Tf1 or Tf2 > 82°C
Tf1 and Tf2 < 60°C
Normal operation
Inverter module temperature protection, error code PL is displayed
Voltage ≥ 260V
or Voltage < 165V
180V ≤ Voltage < 250V
Normal operation
Compressor voltage protection, error code H1 is displayed
When P4 or P5 protection occurs 5
times in 120 minutes, ta manual
system restart is required before the
system can resume operation.
C7 is displayed when PL error occurs
3 times in 100 minutes, a manual
system restart is required before the
system can resume operation.
6.4 Compressor and Inverter Module Protection Control
This control protects the compressors from abnormally high currents and protects the inverter modules from abnormally
high temperatures. It is performed for each compressor and inverter module.
When the compressor current rises above25A, the system displays P4 or P5 protection and all the units stop running.
When the compressor current drops below 25A, the compressor enters re-start control.
When the Tf1 or Tf2 temperature rises above 82°C , the system displays PL protection and all the units stop running. When
the Tf1 and Tf2 temperature drops below 60°C, the compressor enters re-start control.
6.5 Voltage Protection Control
This control protects the units from abnormally high or abnormally low voltages.
When the phase voltage of AC power supply is at or above 260V for more than 30 seconds, the system displays H1
protection and all the units stop running. When the phase voltage drops below 250V for more than 30 seconds, the units
restart once the compressor re-start delay has elapsed. When the phase voltage is below 165V for more than 30 seconds,
the system displays H1 protection and all the units stop running. When the AC voltage rises to at or above 180V for more
than 30 seconds, the refrigerant system restarts once the compressor re-start delay has elapsed.
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Figure 3-6.7: Anti-freeze protection control in normal cooling mode
Note:
1. Taf include Taf1 and Taf2.
Figure 3-6.8: Anti-freeze protection control in low water outlet cooling mode
Note:
1. Taf include Taf1 and Taf2.
Min(Tw/Two/Twi/Taf1) ≤ 4°C
Tw > 15°C
Normal operation
Anti-freeze protection, error code Pb is displayed
Min(Tw/Two/Twi/Taf1) ≤ 0°C
Tw > 15°C
Normal operation
Anti-freeze protection, error code Pb is displayed
6.6 DC Fan Motor Protection Control
This control protects the DC fan motors from abnormal power supply. DC fan motor protection occurs when the fan
module does not receive any feedback from the fan motor.
When DC fan motor protection control occurs the system displays the PU error code and the unit stops running. When PU
protection occurs 2 times in 120 minutes, the FF error is displayed. When an FF error occurs, a manual system restart is
required before the system can resume operation.
6.7 Water Side Heat Exchanger Anti-freeze Protection Control
This control protects the water side heat exchanger from ice formation. The water side heat exchanger electric heater is
controlled according to water side heat exchanger anti-freezing temperature (Taf), water inlet temperature (Twi), water
outlet temperature (Two) and total water outlet temperature (Tw).
When water side heat exchanger anti-freeze protection occurs the system displays error code Pb and all the units stop
running.
In standby or normal cooling mode, either water side heat exchanger anti-freezing temperature (Taf), water inlet
temperature (Twi), water outlet temperature (Two) or total water outlet temperature (Tw) is below 4°C, the unit will run
heating mode , until the total water outlet temperature is above 15°C, and restart the normal operation.
In low water outlet cooling mode, either water side heat exchanger anti-freezing temperature (Taf), water inlet
temperature (Twi), water outlet temperature (Two) or total water outlet temperature (Tw) is below 0°C, the unit will run
heating mode , until the total water outlet temperature is above 15°C, and restart the normal operation.
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Figure 3-6.9: Air side heat exchanger high temperature protection control 1
Note:
1. T3: Air side heat exchanger refrigerant outlet temperature
Figure 3-6.10: Air side heat exchanger temperature protection control 2
Note:
1. Tz/7: Air side heat exchanger refrigerant total outlet temperature
Figure 3-6.11: Water side heat exchanger temperature difference protection control
Notes:
1. Twi: Water side heat exchanger inlet temperature
2. Two: Water side heat exchanger outlet temperature
T3 > 65°C
T3 < 60°C
Normal operation
High temperature protection, error code P7 is displayed
Tz/7 ≥ 62°C
Tz/7 < 62°C
Normal operation
High temperature protection, error code P7 is displayed
∣Twi-Two∣≥ 12°C
∣Twi-Two∣< 6°C
Normal operation
Temperature difference protection, error code P9 is displayed
When P9 protection occurs 3 times
in 60 minutes, a manual system
restart is required before the system
can resume operation.
6.8 Air Side Heat Exchanger High Temperature Protection Control
This control protects the air side heat exchanger from high temperature.
When the air side heat exchanger refrigerant outlet temperature (T3) rises above 65°C , the system displays P7 protection
and all the units stop running. When the air side heat exchanger refrigerant outlet temperature (T3) drops below 60°C, the
compressor enters re-start control.
When the air side heat exchanger refrigerant total outlet temperature (Tz/7) temperature rises at or above 62°C , the
system displays P7 protection and the unit stops running. When the air side heat exchanger refrigerant total outlet
temperature (Tz/7) temperature drops below 62°C, the compressor enters re-start control.
6.9 Water Side Heat Exchanger Temperature Difference Protection Control
This control protects the water side heat exchanger from ice formation.
When the temperature difference rises at or above 12°C , the system displays P9 protection and all the units stop running.
When the Temperature difference drops below 6°C, the compressor enters re-start control.
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Figure 3-6.12: Water side heat exchanger low temperature protection control in normal cooling mode
Notes:
1. Taf1: Water side heat exchanger anti-freezing temperature1
2. Taf2: Water side heat exchanger anti-freezing temperature2
Figure 3-6.13: Water side heat exchanger low temperature protection control in low water outlet mode
Min (Taf1 or Taf2) ≤ 3°C
Min (Taf1 and Taf2) >10°C
Normal operation
Low temperature protection, error code PE is
Min (Taf1 or Taf2) ≤ 0°C
Min (Taf1 and Taf2) > 5°C
Normal operation
Low temperature protection, error code PE is displayed
6.10 Water Side Heat Exchanger Low Temperature Protection Control
This control protects the water side heat exchanger from ice formation.
When water side heat exchanger anti-freezing temperature1 (Taf1) or water side heat exchanger anti-freezing
temperature2 (Taf2) is at or below 3°C for more than 3 seconds, the system displays PE protection and the corresponding
unit stop running. When water side heat exchanger anti-freezing temperature1 (Taf1) and Water side heat exchanger
anti-freezing temperature2 (Taf2) rise to 10°C or higher, the compressor enters re-start control. Use the user interface to
clear the error.
When water side heat exchanger anti-freezing temperature1 (Taf1) or water side heat exchanger anti-freezing
temperature2 (Taf2) is at or below 0°C for more than 3 seconds, the system displays PE protection and orders the
corresponding units to stop running. When water side heat exchanger anti-freezing temperature1 (Taf1) and Water side
heat exchanger anti-freezing temperature2 (Taf2) rise to 5°C or higher, the compressor enters re-start control. Use the user
interface to clear the error.
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Figure 3-6.14: Water side heat exchanger low pressure protection control in normal cooling mode
Note:
1. Pe: Suction pressure
Figure 3-6.15: Water side heat exchanger low pressure protection control in low water outlet cooling mode
Note:
1. Pe: Suction pressure
Pe < 0.6Mpa
Pe ˃ 0.6Mpa
Normal operation
Low pressure protection, error code PC is
Pe < 0.4Mpa
Pe ˃ 0.4Mpa
Normal operation
Low pressure protection, error code PC is
When system displays PC protection
and a manual system restart is
required before the system can
resume operation.
When system displays PC protection
and a manual system restart is
required before the system can
resume operation.
6.11 Water Side Heat Exchanger Low Pressure Protection Control
This control protects the water side heat exchanger from ice formation.
In normal cooling mode, when the suction pressure drops below 0.6Mpa, the system displays PE protection and all the
units stop running. When the suction pressure is above 0.6Mpa or higher, the compressor enters re-start control. It will not
display the PC error when the suction pressure drops below 0.6Mpa for the first time until the suction pressure drops
below 0.6Mpa for the second time in 30 minutes.
In low water outlet cooling mode, when the suction pressure drops below 0.4Mpa, the system displays PE protection and
all the units stop running. When the suction pressure is above 0.4Mpa or higher, the compressor enters re-start control. It
will not display the PC error when the suction pressure drops below 0.4Mpa for the first time until the suction pressure
drops below 0.4Mpa for the second time in 30 minutes.
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Startup control
Normal operation
After defrosting operation or on
restart following compressor stop
after set temperature s reached
Normal operation
Outdoor unit
duty cycling
Priority
1
Priority
2
……
Priority
16
Master
Slave 1
Slave 15
Outdoor unit
duty cycling
Priority
16
Priority
15
Priority
1
Master
Slave 1
Slave 15
……
7 Special Control
7.1 Outdoor Unit Duty Cycling
In systems with multiple outdoor units, outdoor unit duty cycling is used to balance the compressor running time.
Outdoor unit duty cycling occurs whenever all the outdoor units stop running (either because the leaving water set
temperature has been reached or because a master unit error has occurred):
When the outdoor units are powered on for the first time, if there is a load requirement, the units turn on, starting
with the master unit. As the leaving water temperature approaches its set temperature, units shut down in succession,
starting with the unit with the highest address. Once the set temperature has been reached, the master unit shuts
down.
The next time a load requirement exists (or, following a master unit error), the units turn on, starting with the unit
with the highest address. As the leaving water temperature approaches its set temperature, units shut down in
succession, starting with the unit with the lowest address (the master unit). Once the set temperature has been
reached, the unit with the highest address shuts down.
Figure 3-7.1 shows an example of duty cycling in a system with 16 outdoor units.
Figure 3-7.1: Duty cycling in a system with 16 outdoor units
1
Notes:
1. The address settings on the outdoor unit main PCBs for master unit and slave unit do not change.
7.2 Defrosting Operation
In order to recover heating capacity, the defrosting operation is conducted when the outdoor unit air side heat exchanger
is performing as a condenser. The defrosting operation is controlled according to outdoor ambient temperature, air side
heat exchanger refrigerant outlet temperature and the compressor running time.
The defrosting operation ceases when any one of the following three conditions occurs:
Defrosting operation duration reaches 10 minutes.
The air side heat exchanger refrigerant outlet temperature reaches the target temperature.
The water outlet temperature is at or below 5°C .
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