Installing, starting up, and servicing air−conditioning equipment
can be hazardous due to system pressures, electrical components,
and equipment location (roofs, elevated structures, etc.).
Only trained, qualified installers and service mechanics should
install, start−up, and service this equipment.
Untrained personnel can perform basic maintenance functions such
as cleaning coils. All other operations should be performed by
trained service personnel.
When working on the equipment, observe precautions in the
literature and on tags, stickers, and labels attached to the
equipment.
Follow all safety codes. W ear safety glasses and work gloves. Keep
quenching cloth and fire extinguisher nearby when brazing. Use
care in handling, rigging, and setting bulky equipment.
Read this manual thoroughly and follow all warnings or cautions
included in literature and attached to the unit. Consult local building
codes and National Electrical Code (NEC) for special requirements.
!
Recognize safety information. This is the safety−alert symbol
When you see this symbol on the un it and in instructions or manuals,
be alert to the potential for personal injury. Understand these signal
words: DANGER, W ARNI NG, a nd CAUTION.
!
These words are used with the safety−alert symbol. DANGER
identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies hazards whichcould result in personal injury or death. CAUTION is used to
identify unsafe practices which may result in minor personal injury
or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability, or
operation.
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF
position. There may be more than 1 disconnect switch.
Lock out and tag switch with a suitable warning label.
!
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Do not bury more than 36 in. (914 mm) of refrigerant pipe
in the ground. If any section of pipe is buried, there must be
a 6 in. (152 mm) vertical rise to the valve connections on
the outdoor units. If more than the recommended length is
buried, refrigerant may migrate to the cooler buried section
during extended periods of system shutdown. This causes
refrigerant slugging and could possibly damage the
compressor at start−up.
.
WARNING
!
WARNING
EXPLOSION HAZARD
Failure to follow this warning could
result in death, serious personal injury,
and/or property damage.
Never use air or gases containing
oxygen for leak testing or operating
refrigerant compressors. Pressurized
mixtures of air or gases containing
oxygen can lead to an explosion.
CAUTION
INTRODUCTION
This Service Manual provides the necessary information to service,
repair, and maintain the outdoor units. Section 2 of this manual has
an appendix with data required to perform troubleshooting. Use the
Table of Contents to locate a desired topic.
MODEL/SERIAL NUMBER NOMENCLATURES
Table 1—Unit Sizes
SYSTEM TONSBTUhVOLTAGE - PHASEOUTDOOR MODEL
1.0012,000115-138MHRBC12AA1
Cooling Only
Heat Pump
38 = OUTDOOR UNIT
1.0012,000208/230-138MHRBC12AA3
1.5018,000208/230-138MHRBC18AA3
2.0024,000208/230-138MHRBC24AA3
1.0012,000115-138MHRBQ12AA1
0.759,000208/230-138MHRBQ09AA3
1.0012,000208/230-138MHRBQ12AA3
1.5018,000208/230-138MHRBQ18AA3
2.0024,000208/230-138MHRBQ24AA3
OUTDOOR UNIT
38MH3Q
BR09
A
A
VOLTAGE
1 =115-1-60
3 = 208/230-1-60
MH = MODEL
UNIT TYPE
R = OUTDOOR UNIT
MAJOR SERIES
SYSTEM TYPE
C = COOLING ONLY
Q = HEAT PUMP
Week of Manufacture
Year of Manufacture
0118
V
V = ALL MODELS
MAXIMUM NUMBER OF FAN COIL UNITS THAT
CAN BE CONNECTED TO THE OUTDOOR UNIT
A = 1:1
10001
Sequential Serial Number
VARIATIONS
A = STANDARD
NOMINAL CAPACITY
09 - 3/4 TON
12 - 1 TON
18 - 1-1/2 TONS
24 - 2 TONS
Use of the AHRI Certified
TM Mark indicates a
manufacturer’s
participation in the
program For verification
of certification for individual
products, go to
www.ahridirectory.org.
All wires must be sized per NEC (National Electrical Code) or
CEC (Canadian Electrical Code) and local codes. Use Electrical
Data table MCA (minimum circuit amps) and MOCP (maximum
over current protection) to correctly size the wires and the
disconnect fuse or breakers respectively.
Recommended Connection Method for Power and
Communication Wiring:
The main power is supplied to the outdoor unit. The field supplied
14/3 stranded wire with ground with a 600 volt insulation rating,
power/communication wiring from the outdoor unit to indoor unit
consists of four (4) wires and provides the power for the indoor
unit. Two wires are line voltage AC power, one is communication
wiring (S) and the other is a ground wire. Wiring between indoor
and outdoor unit is polarity sensitive. The use of BX wire is NOT
recommended.
If installed in a high Electromagnetic field (EMF) area and
communication issues exists, a 14/2 stranded shielded wire can be
used to replace L2/N and (S) between outdoor unit and indoor unit
landing the shield onto ground in the outdoor unit only.
!
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Wires should be sized based on NEC and local codes.
!
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage
or improper operation.
SBe sure to comply with local codes while running wire from
the indoor unit to the outdoor unit.
SEvery wire must be connected firmly. Loose wiring may
cause the terminal to overheat or result in unit malfunction.
A fire hazard may also exist. Ensure all wiring is tightly
connected.
SNo wire should touch the refrigerant tubing, compressor or
any moving parts.
SDisconnecting means must be provided and shall be located
within sight and readily accessible from the air conditioner.
SConnecting cable with conduit shall be routed through the
hole in the conduit panel.
9
CONNECTION DIAGRAMS
208/230-1-60
FIELD POWER SUPPLY
L1
L2
S
Indoor
Signal
High
Voltage
GND
Main
Power Supply
208/230-1-60
L
N
Indoor Unit
Power Supply
115-1-60
Indoor
Signal
High
Voltage
115-1-60
CONNECTING CABLE
FIELD POWER SUPPLY
OUTDOOR TO INDOOR
N
GND
S
Indoor
Signal
High
Voltage
L
N
Main
Power Supply
115-1-60
GND
S
Ground
L
Power to
Indoor Unit
115-1-60
L1 L2
Indoor Unit
Power Supply
Indoor
Signal
High
208/230-1-60
Voltage
CONNECTING CABLE
OUTDOOR TO INDOOR
GND
S
Ground
Power to
Indoor Unit
208/230-1-60
115V Indoor Unit 115V Outdoor Unit 230V Indoor Unit 230V Outdoor Unit
Fig. 6 – Connection Diagrams
Notes:
1. Do not use thermostat wire for any connection between indoor and outdoor units.
2. All connections between indoor and outdoor units must be as shown. The connections are sensitive to polarity and will result in a fault code.
1 The outdoor units are shipped with a full charge of R410A
refrigerant. All charges, line sizing, and capacities are based
on runs of 25ft. (7.6 m). For runs over 25 ft. (7.6 m),
consult the long−line applications section for the proper
charge adjustments.
2 The minimum refrigerant line length between the indoor
and outdoor units is 10 ft. (3 m).
3 Refrigerant lines should not be buried in the ground. If it is
necessary to bury the lines, not more than 36 in (914 mm)
should be buried. Provide a minimum 6in (152 mm)
vertical rise to the service valves to prevent refrigerant
migration.
T able 12 lists the maximum lengths allowed.
T able 12—Piping and Refrigerant Information
System Size12K (115V)9K (208-230V)12K (208-230V)18K (208-230V)24K (208-230V)
Min. Piping Lengthft. (m)10(3)10(3)10(3)10(3)10(3)
Piping
Refrigerant
Standard Piping Length
Max. outdoor-indoor
height difference
(OU higher than IU)
Max. outdoor-indoor
height difference
(IU higher than OU)
Max. Piping Length with
no additional refrigerant
charge per System
(Standard Piping length)
Total Max. Piping
Length per system
Additional refrigerant
charge (between Standard
– Max piping length)
4 Both lines must be insulated. Use a minimum of 1/2in.
(12.7 mm) thick insulation. Closed−cell insulation is
recommended in all long−line applications.
5 Special consideration should be given to isolating
interconnecting tubing from the building structure. Isolate
the the tubing so vibration or noise is not transmitted into
the structure.
IMPORTANT: Both refrigerant lines must be insulated
separately.
Long Line Applications,:
1 No change in line sizing is required.
2 Add refrigerant per T able 12.
18
SYSTEM EVACUATION AND
t
CHARGING
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Never use the system compressor as a vacuum pump.
Refrigerant tubes and indoor coil should be evacuated using the
recommended deep vacuum method of 500 microns. Always break
a vacuum with dry nitrogen.
System Vacuum and Charge
Using Vacuum Pump
1 Completely tighten all flare nuts and connect manifold gage
charge hose to a charge port of the low side service valve
(see Fig. 14).
2 Connect the charge hose to the vacuum pump.
3 Fully open the low side of manifold gage (see Fig. 15).
4 Start the vacuum pump
5 Evacuate using the triple evacuation method.
6 After evacuation is complete, fully close the low side of
manifold gage and stop the vacuum pump operation.
7 The factory charge contained in the outdoor unit is good
for up to 25 ft. (8 m) of line length. For refrigerant lines
longer than 25 ft. (8 m), add refrigerant as specified in the
ADDITIONAL REFRIGERANT CHARGE table in this
document.
8 Disconnect the charge hose from the charge connection of
the low side service valve.
9 Fully open service valves B and A.
10 Securely tighten the service valves caps.
Outdoor Unit
Service Valve
500 microns
Low side valve
Charge hose
CAUTION
Refrigerant
Low Side
A
High Side
B
Fig. 14 – Service Valve
Manifold Gage
High side valve
Charge hose
Indoor Uni
C
D
Vacuum pump
Deep Vacuum Method
The deep vacuum method requires a vacuum pump capable of
pulling a vacuum of 500 microns and a vacuum gage capable of
accurately measuring this vacuum depth. The deep vacuum method
is the most positive way of assuring a system is free of air and
liquid water (see Fig. 16).
5000
4500
4000
3500
3000
2500
2000
MICRONS
1500
1000
500
01234567
MINUTES
LEAK IN
SYSTEM
V ACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
Fig. 16 – Deep Vacuum Graph
Triple Evacuation Method
The triple evacuation method should be used. Refer to Fig. 17 and
proceed as follows:
1 Pump the system down to 1500 microns and allow the
pump to continue operating for an additional 15 minutes.
2 Close the service valves and shut off the vacuum pump.
3 Connect a dry nitrogen cylinder and regulator to the system
and break vacuum until the system reaches 2 psig.
4 Close the service valve and allow the system to stand for
1hr. During this time, the dry nitrogen can diffuse
throughout the system absorbing moisture.
5 Pump the system down to 1000 microns.
6 Break the vacuum with dry nitrogen (2 psig).
7 Pump the system down to 500 microns.
8 Perform the hold test for 30 minutes.
EVACUATE TO 1500 MICRONS
BREAK VACUUM WITH DRY NITROGEN TO 2 PSIG
EVACUATE TO 1000 MICRONS
BREAK VACUUM WITH DRY NITROGEN TO 2 PSIG
EVACUATE TO 500 MICRONS MINIMUM (HOLD FOR 30 MINUTES)
CHECK FOR TIGHT, DRY SYSTEM
(IF IT HOLDS DEEP VACUUM)
RELEASE CHARGE INTO SYSTEM BY OPENING VALVES COMPLETELY
Fig. 17 – Triple Evacuation Method
Final Tubing Check
IMPORTANT: Check to be certain factory tubing on both
indoor and outdoor unit has not shifted during shipment.
Ensure tubes are not rubbing against each other or any sheet
metal. Pay close attention to feeder tubes, making sure wire ties
on feeder tubes are secure and tight.
Low side valve
Fig. 15 – Manifold
19
Operation Modes and Functions
FAN Mode
1 Outdoor fan and compressor stop
2 Temperature setting function is disabled, and no setting
temperature is displayed.
3 Indoor fan can be set to high/med/low/auto
4 The louver operates the same in the COOLING mode.
5 Auto fan
Fig. 18 – Auto Fan
COOLING Mode
Compressor Running Rules:
SWhen T1*Ts < 28.4_F(*2_C), the compressor stops.
SWhen T1*TS > 31.1_F(*0.5_C), the compressor
activates.
SWhen the AC runs in the mute mode, the compressor
runs with low frequency.
SWhen the current is more than setting value, the current
protection function activates, and the compressor stops.
Outdoor Fan Running Rules:
The outdoor unit runs at a different fan speed according to T4. For
different outdoor units, the fan speeds differ.
Fig. 20 – Auto Fan
Fig. 21 – Compressor Temperature Protection
When the condenser temperature temperature is higher than the
setting value, the compressor stops.
Compressor Running Rules
When T1−Ts>−ΔT, the compressor stops, when
<ΔT−1.5,the compressor will be on. ΔT is the
T1−T
S
programmed parameter of temperature compensation. When the
AC run in mute mode, the compressor runs with low frequency.
When the current is more than setting value, the current protection
function is activated and the compressor stops.
Outdoor Fan Running Rules
The outdoor unit runs at different fan speed according to T4. For
different outdoor units, the fan speeds are different.
Fig. 19 – Outdoor Fan Running Rules
The auto fan adheres to the following rules.
Fig. 22 – Outdoor Fan Running Rules
20
Auto Fan Action in HEATING Mode
T1
a
b
c
d
e
Fig. 23 – Auto Fan Action in HEATING Mode
DEFROST Mode
The air conditioner enters the DEFROST mode according to the
T3 temperature value and the T3 temperature change value range
plus the compressor running time.
During the DEFROST mode, the compressor continues to runs,
the indoor and outdoor motors stop, and the indoor unit defrost
lamp illuminates and
If any one of the following items is satisfied, the defrosting finishes
and the machine reverts to the normal heating mode.
−−−−T3 rises to be higher than TCDE1
−−−−T3 keeps to be higher than TCDE2
−−−−The machine has run for 15 minutes in defrosting mode.
Evaporator Coil Temperature Protection
appears.
_C.
_C for 80 seconds.
T2
TEstop
TEdown
TEH2
Off
Decrease
Hold
Resume
Table 13—Auto Mode
ΔT=T1-TsRunning mode
ΔT>2_C
-2≤ΔT≤2_C
ΔT<-2_C
The indoor fan runs under auto fan in the relevant mode. The louver
operates the sam e i n the r elevant mode . I f the machine switches modes
between HEATI NG and COOLING, the compressor stops for 15
minutes and then chooses the mode according to T1−Ts. If the setting
temperature is modified, the machine chooses the running function
again.
DRY mode
Indoor fan speed is fixed at breeze and can not be changed.
The louver angle is the same as in the cooling mode.
Low indoor room temperature protection
In the DRYING mode, if the room temperature is lower than 50_F
_C), the compressor stops and does not resume until the room
(10
temperature exceeds 53.6
Evaporator anti*freezing protection, condenser high temperature
protection and outdoor unit frequency limit are active and are the
same as that in the cooling mode. The outdoor fan operates the
same as in cooling mode.
Forced Operation Function
_F (12_C).
Cooling
Fan-only
Heating
SEnter forced operation function: When the machine is
off, press Touch to engage the the Forced Auto Mode.
Press Touch again, within 5 seconds, to engage the
Forced Cooling Mode. In Forced Auto, forced cooling
or any other operation mode, press the touch button to
turn off the unit. In the forced operation mode, all
general protections and remote control are available.
Operation rules:
SForced Cooling Mode: The compressor runs at the F2
frequency and the indoor fan runs as a breeze. After
running for 30 minutes, the unit enters the auto mode as
75.2_F (24_C) setting temperature.
SForced Auto Mode: The forced auto mode is the same
as the normal auto mode with a 75.2_F (24_C) setting
temperature.
Fig. 24 – Evaporator Coil Temperature Protection
NOTE: The following applies to Fig. 24:
SOff: Compressor stops
SDecrease: Decrease the running frequency to the lower level
SHold: Keep the current frequency
SResume: No limitation for frequency
When the evaporator temperature is higher than the setting
protection value, the compressor stops.
Auto−Mode
This mode can be chosen with the remote controller and the setting
temperature can be changed between 62.6
In the AUTO mode, the machine chooses the COOLING,HEATING or FAN−ONLY mode according to ΔT (ΔT =T1−Ts).
_F(17_C)~86_F(30_C).
AUTO−RESTART Function
The indoor unit is equipped with the AUTO−REST AR T
function, which is carried out through an auto−restart module. In
the event of a sudden power failure, the module memorizes the
setting conditions prior to the power failure. The unit resumes the
previous operation setting (not including the SWING function)
automatically three (3) minutes after the power returns.
If the memorization condition is the FORCED COOLING mode,
the unit will run in the COOLING mode for 30 minutes and turn
to the AUTO mode at the 75.2_F(24_C) setting temperature.
If the air conditioner is off before the power turns off and the air
conditioner is required to start up, the compressor delays start up
for 1 minute before powering on. In other instances, the
compressor waits three (3) minutes before restarts.
Refrigerant Leak Detection
With this new technology, the display area displays “EC” when the
outdoor unit detects a refrigerant leak. This function is only active in
cooling mode. It can better prevent the compressor being damaged by
refrigerant leakage or compressor overload.
Open Condition: When the compressor is active, the value of the Coil
temperature o f evaporator T2 has no c hange or v ery little ch ange.
46_F (8_C) Heating
When the compressor is running, the indoor fan motor runs
without the ANTI−COLD air function. When the compressor is
off, the indoor fan motor is off.
21
Point Check Function
Press the remote controller’s LED DISPLAY or LED or MUTE button three times, and then press the AIR DIRECTION or SWING
button three times in ten seconds, the buzzer rings for two seconds. The air conditioner enters into the information enquiry status.
Press the LED DISPLAY or AIR DIRECTION button to check the next or front item’s information.
When the air conditioner enters the information enquiry status, it displays the code name in 2 seconds (see Table 14).
T able 14—Information Enquiry
ENQUIRY INFORMATIONDISPLAYING CODEMEANING
T1T1T1 temp.
T2T2T2 temp.
T3T3T3 temp.
T4T4T4 temp.
T2BTbT2B temp.
TPTPTP temp.
THTHTH temp.
Targeted FrequencyFTTargeted Frequency
Actual FrequencyFrActual Frequency
Indoor Fan SpeedIFIndoor fan speed
Outdoor Fan SpeedOFOutdoor fan speed
EXV Opening AngleLAEXV opening angle
Compressor continuous running timeCTCompressor continuous running time
Compressor stop causesSTCompressor stop causes
ReserveA0
ReserveA1
Reserveb0
Reserveb1
Reserveb2
Reserveb3
Reserveb4
Reserveb5
Reserveb6
ReservedL
ReserveAc
ReserveUo
ReserveTd
When the air conditioner enters the information enquiry status, it displays the code value for 25 seconds (see Table 15).
ENQUIRY
INFORMATION
T1,T2,T3,T4,
T2B,TP,TH,
Targeted
Frequency,
Actual
Frequency
Indoor fan speed
/Outdoor fan speed
EXV opening angle0-FF
Compressor
continuous running
time
Compressor stop
causes
Reserve0-FF
DISPLAY VALUEMEANINGREMARK
-1F,-1E,-1d,-1c,
-1b,-1A
-19—99-19—99
A0,A1,…A9100,101,…109
b0,b1,…b9110,111,…119
c0,c1,…c9120,121,…129
d0,d1,…d9130,131,…139
E0,E1,…E9140,141,…149
F0,F1,…F9150,151,…159
0OFF
1,2,3,4
14-FF
0-FF0-255 minutes
0-99
T able 15—Information Enquiry
-25,-24,-23,-22,-21,-20
Low speed, Medium speed, High
Actual fan speed = Display value
For the detailed meaning, please
speed, Turbo
turns to decimal value and then
multiply 10. The unit is RPM.
Actual EXV opening value =
Display value turns to decimal
value and then multiply 2.
consult with engineer
1. The displaying temperature is the actual value.
2. The temperature is _C no matter what kind of remote
controller is used.