Hvac CVH8 User manual

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
1
APPLICATION GUIDELINE & SERVICE MANUAL
TABLE OF CONTENTS
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
REFRIGERANT PIPING LENGTH LIMITATIONS . . . . . . . . . . . . 3
LONG LINE APPLICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
ELECTRICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Aluminum Wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Unit Electrical Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
MAJOR COMPONENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
COMMUNICATION and STATUS FUNCTION LIGHTS . . . . . . . 6
Check Charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
FAULT CODES / DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . . . 13
Variable Speed Drive LED Location and Description (Sizes 25, 36,
37, 48, 49 and 60). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Variable Speed Drive LED Location and Description (Size 24) . 25
COMPRESSOR POWER HARNESS ASSEMBLY REPLACE-
MENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
SmartSense Assembly w/Shield Gasket Removal and Installation28
COMPRESSOR REPLACEMENT . . . . . . . . . . . . . . . . . . . . . . . 31
WIRING DIAGRAMS - *VA9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
WIRING DIAGRAMS - *VH8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
REFRIGERATION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Refrigerant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Compressor Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Servicing Systems on Roofs With Synthetic Materials . . . . . . . . 36
Brazing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Service Valves and Pumpdown . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Pumpdown & Evacuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Liquid Line Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Suction Line Filter Drier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Thermostatic Expansion Valve (TXV) . . . . . . . . . . . . . . . . . . . . 38
Accumulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
REFRIGERATION SYSTEM REPAIR. . . . . . . . . . . . . . . . . . . . . . 39
Leak Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Coil Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service, maintenance, or
use can cause explosion, fire, electrical shock, or other conditions which
may cause death, personal injury, or property damage. Consult a
qualified installer, service agency, or your distributor or branch for
information or assistance. The qualified installer or agency must use
factory–authorized kits or accessories when modifying this product.
Refer to the individual instructions packaged with the kits or accessories
when installing.
Follow all safety codes. Wear safety glasses, protective clothing, and
work gloves. Use quenching cloth for brazing operations. Have fire
extinguisher available. Read these instructions thoroughly and follow all
warnings or cautions included in literature and attached to the unit.
Consult local building codes and current editions of the National
Electrical Code (NEC) NFPA 70. In Canada, refer to current editions of
the Canadian electrical code CSA 22.1.
Recognize safety information. This is the safety–alert symbol . When
you see this symbol on the unit and in instructions or manuals, be alert to
the potential for personal injury.
Understand these signal words; DANGER, WARNING, and 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 which could 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.
CVH8, HVH8, TVH8, VA9, HVA9, TVA9
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
!
CUT HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care and wear
appropriate protective clothing and gloves when handling parts.
WARNING
!
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could result in personal injury or
equipment damage.
R-410A systems operate at higher pressures than standard R-22
systems. Do not use R-22 service equipment or components on R-410A
equipment. Ensure service equipment is rated for R-410A.

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
2
Table 1 – OUTDOOR UNIT MODEL NUMBER IDENTIFICATION GUIDE
Digit Position: 1 2 3 4 5, 6 7 8 9 10 11 12
Example Part
Number: * V A 9 24 G K A 1 0 0
* = Brand
V = Variable Speed
KEY CHARACTERISTIC
A = Air Conditioner
H = Heat Pump TYPE
6 = 16 SEER
7 = 17 SEER
8 = 18 SEER
9 = 19 SEER NOMINAL EFFICIENCY
24 = 24,000 BTUH = 2 tons
25 = 24,000 BTUH = 2 tons
36 = 36,000 BTUH = 3 tons
37 = 36,000 BTUH = 3 tons
48 = 48,000 BTUH = 4 tons
49 = 48,000 BTUH = 4 tons
60 = 60,000 BTUH = 5 tons NOMINAL CAPACITY
G = Coil Guard Grille FEATURES
K = 208-230-1-60 VOLTAGE
Sales Code
Engineering Revision
Extra Digit
Extra Digit

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
3
REFRIGERANT PIPING LENGTH LIMITATIONS
Maximum Line Lengths:
The maximum allowable total equivalent length varies depending on the vertical separation. See the tables below for allowable lengths depending on
whether the outdoor unit is on the same level, above or below the outdoor unit.
LONG LINE APPLICATIONS
Unit is approved for up to 100 ft (30.5 m) equivalent length and vertical
separations shown above with no additional accessories.
Longer line set applications are not permitted.
Refrigeration systems contain refrigerant under pressure. Extreme
caution should be observed when handling refrigerants. Wear safety
glasses and gloves to prevent personal injury. During normal system
operations, some components are hot and can cause burns. Rotating fan
blades can cause personal injury. Appropriate safety considerations are
posted throughout this manual where potentially dangerous techniques
are addressed.
If you do not understand any of the warnings, contact your product
distributor for better interpretation of the warnings.
GENERAL INFORMATION
The *VH8 & VA9 split system heat pump and air conditioners features
a new outdoor cabinet design that uses a four-sided coil design to
minimize the unit footprint and provide the best heat exchange taking
full advantage of the latest variable speed technology.
The heart of the system is the variable speed rotary compressor powered
through the use of the variable speed drive (VSD) inverter control.
Through the use of R-410A refrigerant, compact ECM outdoor fan
motor, VSD and variable speed rotary compressor, along with the new
outdoor cabinet, the unit achieves a Seasonal Energy Efficiency Ratio
(SEER) of up to 19 and up to 11 Heating Seasonal Performance Factor
(HSPF).
To ensure ultimate comfort, these units should be combined with either
the FCM fan coil or Variable Speed Gas furnace controlled with a two
wire communication TSTAT0201CW with version 5.0 software or
newer. This combination will ensure achievement of comfort with the
convenience of fingertip trouble shooting and diagnostic capability.
These units can also use a standard, 2-stage or single-stage thermostat,
for limited functionality.
ELECTRICAL
Table 2 – Maximum Line Lengths
MAXIMUM ACTUAL LENGTH
ft (m)
MAXIMUM EQUIVALENT LENGTH*
ft (m)
*. Total equivalent length accounts for losses due to elbows or fitting. See the Long Line Guideline for details.
MAXIMUM VERTICAL
SEPARATION ft (m)
Units on equal level 100 (30.5) 100 (30.5) N/A
Outdoor unit ABOVE
indoor unit 100 (30.5) 100 (30.5) 100 (30.5)
Outdoor unit BELOW
indoor unit See Table ’Maximum Total Equivalent Length: Outdoor Unit BELOW Indoor Unit’
Table 3 – Maximum Total Equivalent Length* - Outdoor Unit BELOW Indoor Unit
*. Maximum actual length not to exceed 100 ft (30.5 m). Total equivalent length accounts for losses due to elbows or fittings.
-- = outside acceptable range
Size
Liquid Line
Diameter
w/ TXV
HP with R-410A Refrigerant - Maximum Total Equivalent Length{
Vertical Separation ft (m) Outdoor unit BELOW indoor unit;
0-20
(0 - 6.1)
21-30
(6.4 - 9.1)
31-40
(9.4 - 12.2)
41-50
(12.5 - 15.2)
51-60
(15.5 - 18.3)
61-70
(18.6 - 21.3)
71-80
(21.6 - 24.4)
2-Ton 3/8 100* 100* 100* 100* 100* 100* 100*
3-Ton 3/8 100* 100* 100* 100* 100* 100* 100*
4-Ton 3/8 100* 100* 100* 100* 100 100 --
5-Ton 3/8 100* 100* 100* 100* 100 100 --
WARNING
!
ELECTRICAL HAZARD - HIGH VOLTAGE!
Failure to follow this warning could result in personal injury or death.
Electrical components may hold charge. DO NOT remove control box
cover for 2 minutes after power has been removed from unit.
PRIOR TO TOUCHING ELECTRICAL COMPONENTS:
Verify zero (0) voltage at inverter connections shown on inverter cover.
WARNING
!
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.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Exercise extreme caution when working on any electrical components.
Shut off all power to system prior to troubleshooting. Some
troubleshooting techniques require power to remain on. In these
instances, exercise extreme caution to avoid danger of electrical shock.
ONLY TRAINED SERVICE PERSONNEL SHOULD PERFORM
ELECTRICAL TROUBLESHOOTING.

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
4
Aluminum Wire
Whenever aluminum wire is used in branch circuit wiring with this unit,
adhere to the following recommendations.
Connections must be made in accordance with the National Electrical
Code (NEC), using connectors approved for aluminum wire. The
connectors must be UL approved (marked Al/Cu with the UL symbol)
for the application and wire size. The wire size selected must have a
current capacity not less than that of the copper wire specified, and must
not create a voltage drop between service panel and unit in excess of 2 of
unit rated voltage. To prepare wire before installing connector, all
aluminum wire must be “brush-scratched” and coated with a corrosion
inhibitor such as Pentrox A. When it is suspected that connection will be
exposed to moisture, it is very important to cover entire connection
completely to prevent an electrochemical action that will cause
connection to fail very quickly. Do not reduce effective size of wire,
such as cutting off strands so that wire will fit a connector. Proper size
connectors should be used. Check all factory and field electrical
connections for tightness. This should also be done after unit has reached
operating temperatures, especially if aluminum conductors are used.
Unit Electrical Power
Power wires from the unit’s disconnect should be routed through the
power wiring hole provided at the bottom of the unit’s control box.
Connect the ground wire to the ground connection in the control box and
connect the power wiring to the terminal block as shown on the wiring
and Installation Instructions supplied with the unit. The unit does not
require a contactor or outdoor unit transformer in order to operate.
MAJOR COMPONENTS
Application Operational Control Board (AOC)
A160120
Fig. 1 – AOC (Application Operational Control) Board
The AOC board is located in the lower right hand side of inverter tray.
It’s functions include:
• Compressor speed control
• Outdoor fan motor control
• Reversing valve operation
• Defrost operation
• Crankcase heater operation
• Pressure switch monitoring
• Time Delays
• Pressure Transducer measurements
• PEV control (pressure equalizer valve)
• Temperature measurements
• EXV (Electronic Expansion Valve) operation control
• Inverter communication and control
CAUTION
!
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this caution may result in equipment damage or
improper operation.
Aluminum wire may be used in the branch circuit (such as the circuit
between the main and unit disconnect), but only copper wire may be
used between the unit disconnect and the unit.

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
5
Inverter
The inverter is located inside the control box. This is an air-cooled
device that communicates with the control board and drives the
compressor and fan motor to the demanded RPM. The inverter is always
powered with line voltage since no contactor is used. The inverter
changes the line voltage to DC volts and then recreates 3 phase sine
waves that vary in frequency to drive the compressor and fan motor at
the desired RPM.
NOTE: The unit may be operated with an Observer Wall Control or a
standard 2-stage HP thermostat. Observer Wall Control will utilize 5
stages of heating and cooling, while 2-stage HP thermostat will only
allow 2 discrete stages of heating and cooling operation.
Variable Speed Compressor
This unit contains a variable speed rotary compressor that has a wide
operating range. It operates on a variable 3 phase sine wave provided by
the inverter. This compressor can only be operated by the specific
inverter supplied with the unit.
Electronic Expansion Valve (EXV)
This unit uses an electronic expansion valve for refrigerant metering in
the heating mode. The control board drives the EXV to its proper
position based on the operating mode and conditions. The Observer Wall
Control Service mode allows for manual opening and closing of the
EXV for troubleshooting and pump down.
Outdoor Fan Motor
The compact ECM outdoor fan motor is a variable-speed brushless DC
(BLDC) motor that operates at speeds from 400 to 1050 RPM. The
motor is a 3-phase permanent magnet-type motor. Just like the
compressor, this motor speed is determined by the inverter output
frequency and amplitude.
Motor speed is controlled through the inverter board in the outdoor unit
and no electronic module is attached. Motor speed is slowed as the
building load decreases, maintaining the proper condensing temperature
for both cooling and dehumidification. As the building load increases,
the motor will increase speed until it is at maximum speed at the
maximum building load.
At unit start-up, there is a slight delay and thrust motion of the fan
motor/blade in the reverse direction, prior to ramping-up the fan
assembly.
Pressure Transducer (SPT)
A 5 VDC output low pressure transducer that provides a 0-5 VDC data
for interpretation by the control board for a 0 to 200 psig range of
pressure at the suction tube. This interpreted pressure data is then
intelligently used by the AOC control board for low pressure cut-out,
loss of charge management, compressor protection, oil circulation
management, lubrication management and EXV control.
Pressure Equalizer Valve (PEV)
At the end of every compressor operation (after the 3.5 minute Time
Guard period), the equalizer valve opens for 150 seconds plus an
additional 15 seconds of protection before allowing the compressor to
start ramping up.
The PEV is located next to the suction and discharge of the compressor.
The function of this valve is to prevent the compressor from starting with
a high refrigerant pressure differential, thus helping the reliability of the
compressor.
NOTE: A hissing sound may be heard during the equalization process.
This is normal.
Outdoor Coil Thermistor (OCT)
The outdoor coil thermistor is a 10Kohm resistor used for multiple
system operations. It provides the coil/liquid line temperature to the heat
pump board and user interface. Low ambient operation, defrost
initiation, defrost termination and assistance with OAT temperature
measurement of some of the functions (see Fig.2) . The sensor must be
securely mounted to the tube connecting the EXV and distributor. See
Fig. 3 and Fig. 4 for proper placement. See Table 5 for proper
resistances.
A11142
Fig. 2 – OAT Thermistor Location (Bottom of Control Box)
A14302
Fig. 3 – HP Outdoor Coil Thermistor (OCT) Attachment
(On Distributor Tube)
A14328
Fig. 4 – AC Outdoor Coil Thermistor (OCT) Attachment
(On Distributor Tube)
CAUTION
!
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage and/or
improper operation.
Do not attempt to apply line voltage directly to the compressor. This
will destroy the compressor.

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
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6
Suction Thermistor (OST)
Suction Thermistor is used for assisting in EXV control and must be
secured on the suction tube and aligned longitudinally to the vertical
surface of the tube axis (see Fig. 5).
A14023A
Fig. 5 – Suction Thermistor (OST) Attachment
(On Suction Tube)
Discharge Thermistor (ODT)
Discharge Thermistor is used for protection against over temperature of
the compressor. The ODT is located on the compressor discharge
stub-out (see Fig. 6).
A14024
Fig. 6 – Discharge Thermistor (ODT)
Crankcase Heater Operation
This unit has an internal crankcase heater that will be energized during
the off cycle and is intelligently demanded by the system to prevent the
compressor from being the coldest part of the system thus enhancing the
reliability. The crankcase heater will function as needed any time the
outdoor unit is powered. The indoor unit and UI do not need to be
installed for the crankcase heater to operate properly.
The compressor windings will occasionally be energized during the OFF
cycle (depending on the length of the OFF cycle) to start the stator heat
operation, thus maintaining a sump temperature that is essential for
compressor reliability. The compressor will not run during this process.
Time Delays
The unit time delays include:
• 3.5 minute time delay after last cycle, initial power up, return from
brown-out condition. To bypass this feature, momentarily short and
release Forced Defrost pins.
• At the end of every compressor ON cycle, there will be 150 seconds
of PEV open period for pressure equalization followed by 15 seconds
of PEV Off period before the next compressor ON cycle. This delay
cannot be bypassed as it helps compressor reliability.
• 15 second delay at termination of defrost before the auxiliary heat is
de-energized.
• 10 minute sump warm-up delay. This delay is at the beginning of each
high voltage power up.
COMMUNICATION AND STATUS FUNCTION
LIGHTS
Observer Wall Control, Green Communications (COMM) Light
A green LED (COMM light) on the outdoor board (see Fig. 7 and Fig. 8)
indicates successful communication with the other system products. The
green LED will remain OFF until communication is established. Once a
valid command is received, the green LED will turn ON continuously. If
no communication is received within 2 minutes, the LED will be turned
OFF until the next valid communication. The green LED will be turned
off when using a standard 2-stage non-communicating heat pump
thermostat.
Amber Status Light
Amber colored STATUS light indicates operation and error status. See
Table 10 for definitions.
• Two minute time delay to return to standby operation from last valid
communication.
Defrost
This wall control (WC) offers 4 possible defrost interval times: 30, 60
and 90 minutes, or AUTO. The default is AUTO.
Defrost interval times: 30, 60, and 90 minutes or AUTO are selected by
the Observer Wall Control User Interface if using UI. The 90 minute
selectio°n will default to 60 minutes at ambient below 37°F. The UI
setting will supersede the dip switch settings on the control board if not
the same.
If using non-communicating thermostat, defrost intervals are set using
dip switches on outdoor control board (see Fig. 7 and 8). AUTO defrosts
adjusts the defrost interval time based on the last defrost time as follows:
• When defrost time <5 minutes, the next defrost interval=90 minutes.
(outdoor temperature above 37°F)
• When defrost time 5-7 minutes, the next defrost interval=60 minutes.
• When defrost time >7 minutes, the next defrost interval=30 minutes.
The control board accumulates compressor run time. As the accumulated
run time approaches the selected defrost interval time, the control board
monitors the coil temperature sensor for a defrost demand. If a defrost
demand exists, a defrost cycle will be initiated at the end of the selected
time interval. A defrost demand exists when the coil temperature is at or
below 32°F (0°C) for 4 minutes during the interval. If the coil
temperature does not reach 32°F (0°C) within the interval, the interval
timer will be reset and start over.
• Upon initial power up the first defrost interval is defaulted to 30
minutes. Remaining intervals are at selected times.
• Defrost is only allowed to occur below 50°F (10°C) outdoor ambient
temperature.
The defrost cycle is terminated as described below.
• When OAT is > 25°F (+3.89°C), defrost terminates if outdoor coil
temperature (OCT) > 60°F (+15.6°C). And a minimum of one (1)
minute defrost length.
• When OAT ? 25°F (+3.89°C), defrost will terminate if OCT is >45°F
(+4.4°C) and a minimum of 2 minutes defrost length.
• Or 10 minutes has passed.
At the defrost termination, the outdoor fan will turn on 10 seconds
before the reversing valve switching.
NOTE: Compressor speed during defrost will go to defrost speed.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or
improper operation.
In order to minimize the ambient influence, make sure the thermistor
curved surface hugs the pipe surface and is secured tight using the wire
tie fished through the original slot insulating polymer body.

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
7
A150034
Fig. 7 – AOC Control Board for 1 and 2 Ton
A14021
Fig. 8 – AOC Control Board for 3, 4 and 5 Ton
CHECK CHARGE
Charging Procedure: Force system to operate in high stage cooling by
creating a large differential between room temperature and set point on
thermostat. Use multi-meter to verify that 24 VAC is present between C,
Y1 /Y2 terminals at outdoor unit.
Factory charge amount is shown on unit rating plate for high stage.
Target subcooling chart is provided on back of control box door see
Fig. 9 - Fig. 21 for example. To properly check or adjust charge,
condition must be favorable for subcooling charging. Favorable
conditions exists when outdoor temperature is between 65°F (18°C) and
100°F (38°C), and the indoor temperature is between 70°F (21°C) and
80°F (27°C). Follow the procedure below:
Unit is factory charged for 15ft (4.57 m) of lineset. Adjust charge by
adding or removing 0.6 oz/ft (17.7 g/m) of 3/8 liquid line above or below
15ft (4.57 m) respectively. Inaccurate charging may result in nuisance
fault codes.
For standard refrigerant line lengths (80ft/24.4 m or less), allow system
to operate in cooling mode at least 25 minutes. If conditions are
favorable, check system charge by subcooling method. If any adjustment
is necessary, adjust charge slowly and allow system to operate for 25
minutes to stabilize before declaring a properly charged system.
If the indoor temperature is below 70°F (21.11°C), or the outdoor
temperature is not in the favorable range, adjust charge for line set length
above or below 15ft (4.57 m) and indoor fan coil /furnace coil per
Table 4 and Table 5. Charge level should then be appropriate for the
system to achieve rated capacity. The charge level should then be
checked at another time when the both indoor and outdoor temperatures
are in a more favorable range.
NOTE: If the line length is beyond 80ft (24.38 m) or greater than 20ft
(6.10 m) vertical separation see Long line guideline for special charging
requirement.
Table 4 – Required Charge Adjustment for Indoor Coil Model - HP
Furnace Coil or
Fan Coil
Model
Number
24 25 36 37 48 60
EA*4X24 / / / / / /
EHD4X24 / / / / / /
EHD4X30 / / / / / /
F(V,C)M4X24 - - - - / /
EA*4X30 - / / / / /
EN(A,D)4X30 - / / / / /
ENH4X36 - - - - / /
F(V,C)M4X36 - - - - / /
EA*4X36 - - - - / /
END4X42 +.50 - - +.75 / /
EA*4X42 +.50 - - +.75 / /
EHD4X36 / - - +.75 / /
EHD4X42 / +.75 +.75 +.75 / /
EN(A,D)4X31 / +.75 +.75 +.75 / /
EN*4X48 / +.75 +.75 +.75 - /
EHD4X48 / +.75 +.75 +1.00 - /
EN(A,D)4X37 / / / / / /
EN(A,D)4X43 / / / / / /
EA*4X48 / / +.75 +1.00 - /
EN*4X60 / / / +1.00 - -
EHD4X60 / / / +1.00 - -
F(V,C)M4X48 / +.75 +.75 +1.00 - /
F(V,C)M4X60 / / / +1.00 +2.2 +1.00
EA*4X60 / / / / +2.2 +1.00
EN*4X61 / / / / / /
/ = Comb. not allowed
- = No charge adjust for ID
Note: Charge adders are in decimal format

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
8
A200328
Fig. 9 – Charging in Cooling Mode CVH8, HVH8, TVH824
A200329
Fig. 10 – Charging in Cooling Mode CVH8, HVH8, TVH825
A200330
Fig. 11 – Charging in Cooling Mode CVH8, HVH8, TVH836
A200331
Fig. 12 – Charging in Cooling Mode CVH8, HVH8, TVH837
A200332
Fig. 13 – Charging in Cooling Mode CVH8, HVH8, TVH848
A200333
Fig. 14 – Charging in Cooling Mode CVH8, HVH8, TVH860
Table 5 – Required Charge Adjustment for Indoor Coil Model - AC
Furnace Coil
or Fan Coil
Model
24 25 36 37 48 49 60
EA*4X24 - - / / / / /
EHD4X24 - - / / / / /
EHD4X30 - - / / / / /
F(V,C)M4X24 / - - / / / /
EA*4X30 - - / / / / /
EN(A,D)4X30 - - / / / / /
ENH4X36 - - - - / / /
F(V,C)M4X36 / - - - / / /
EA*4X36 - +.50 - - / / /
END4X42 +.50 +.50 - +.75 / / /
EA*4X42 +.50 +.50 - +.75 / / /
EHD4X36 +.50 +.50 - +.75 / / /
EHD4X42 +.50 +.50 +.75 +.75 / / /
EN(A,D)4X31 +.50 +1.25 +.75 +.75 / / /
EN*4X48 +.50 +1.25 +.75 +.75 - - /
EHD4X48 +.63 +1.25 +.75 +1.00 - - /
EN(A,D)4X37 +.63 +1.25 +.75 +1.00 - - /
EN(A,D)4X43 +.63 +1.25 +.75 +1.00 - - /
EA*4X48 / / +.75 +1.00 - - /
EN*4X60 / / / +1.00 - +.13 -
EHD4X60 / / / +1.00 - +.13 -
F(V,C)M4X48 .63 +1.25 +.75 +1.00 - +.13 /
F(V,C)M4X60 / / +.75 +1.00 +1.50 +.63 +1.00
/ = Comb. not allowed
- = No charge adjust for ID

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
9
A200126
Fig. 15 – Charging in Cooling Mode CVA9, HVA9, TVA924
A200127
Fig. 16 – Charging in Cooling Mode CVA9, HVA9, TVA925
A200128
Fig. 17 – Charging in Cooling Mode CVA9, HVA9, TVA936
A200129
Fig. 18 – Charging in Cooling Mode CVA9, HVA9, TVA937
A200130
Fig. 19 – Charging in Cooling Mode CVA9, HVA9, TVA948
A200131
Fig. 20 – Charging in Cooling Mode CVA9, HVA9, TVA949
A200132
Fig. 21 – Charging in Cooling Mode CVA9, HVA9, TVA960
Heating Check Chart Procedure (See Fig.22 - 27)
In heating mode, the required charging method is by weigh-in. On new
installations or complete recharge, refer to the unit rating plate and
indoor fan coil / furnace coil per Table 4 and Table 5 for additional
charge needed. Refrigerant charge adjustment amount for adding or
removing 0.6 oz/ft (17.74 g/m) of 3/8 liquid line above or below 15ft
(4.57 m) respectively.
To use the Heating Check Chart, operate system at Y1+Y2–high stage.
These charts indicate whether a correct relationship exists between
system operating pressure and air temperature entering indoor and
outdoor units. If pressure and temperature do not match on chart, system
refrigerant charge may not be correct. DO NOT USE CHART TO
ADJUST REFRIGERANT CHARGE.
NOTE: High pressure is at vapor service valve. Add 12 psig if high
pressure is taken from liquid service valve.
NOTE: When charging is necessary during heating season, charge must
be weighed in accordance with unit rating plate, ±0.6 oz./ft (±17.74
g/m). of 3/8-in. liquid-line above or below 15 ft (4.57 m), respectively.

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
10
A200334
Fig. 22 – Heating Pressure Check Chart CVH8, HVH8, TVH824
A200335
Fig. 23 – Heating Pressure Check Chart CVH8, HVH8, TVH825
A200336
Fig. 24 – Heating Pressure Check Chart CVH8, HVH8, TVH836
A200337
Fig. 25 – Heating Pressure Check Chart CVH8, HVH8, TVH837
A200338
Fig. 26 – Heating Pressure Check Chart CVH8, HVH8, TVH848
A200339
Fig. 27 – Heating Pressure Check Chart CVH8, HVH8, TVH860
Troubleshooting
Systems Communication Failure
If communication is lost with the wall control (WC), the green LED will
go out. Check the wiring to the wall control and the indoor and outdoor
units and power.
Model Plug
Each control board contains a model plug. The correct model plug must
be installed for the system to operate properly (see Table 6).
The model plug is used to identify the type and size of unit to the control.
On new units, the model and serial numbers are inputted into the AOC
board’s memory at the factory. If a model plug is lost or missing at initial
installation, the unit will operate according to the information input at
the factory and the appropriate error code will flash temporarily. An
RCD replacement AOC board contains no model and serial information.
If the factory control board fails, the model plug must be transferred
from the original board to the replacement board for the unit to operate.
When installing heat pump with older fan coils, a model plug change
may be required.
NOTE: The model plug takes priority over factory model information
input at the factory. If the model plug is removed after initial power up,
the unit will operate according to the last valid model plug installed, and
flash the appropriate fault code temporarily.
Table 6 – Factory Supplied Model Plug Information
CVH8, HVH8,
TVH8
FAST PART
NUMBER
PIN RESISTANCE (K-OHMS)
Pins 1-4 (R1) Pins 2-3
(R2)
24 1184941 18K 75K
25 1188069 18K 11K
36 1184943 18K 120K
37 1188070 18K 24K
48 1184945 18K 180K
60 1184947 18K 270K

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11
Status Codes
Table 10 shows the status codes flashed by the amber status light. Most
system problems can be diagnosed by reading the status code as flashed
by the amber status light on the control board.
The codes are flashed by a series of short and long flashes of the status
light. The short flashes indicate the first digit in the status code,
followed by long flashes indicating the second digit of the error code.
The short flash is 0.25 seconds ON and the long flash is 1.0 second ON.
Time between flashes is 0.25 seconds. Time between short flash and
first long flash is 1.0 second. Time between code repeating is 2.5
seconds with LED OFF.
Codes are easily read from wall control (WC)
EXAMPLE:
3 short flashes followed by 2 long flashes indicates a 32 code. Table 10
shows this to be low pressure switch open.
Status Code Recall Mode
Active status codes are stored in memory even when power is absent.
The most recently flashing status code (highest priority active) can be
recalled from memory via status code recall mode and displayed using
the amber LED. The status code recall mode is accessed by shorting (use
a clip wire) the “force defrost” connector (labeled J2 on the board) and
then power ON the unit. Please make sure the unit is turned OFF before
shorting the pins. Status call recall mode will continue as long as the
“force defrost” terminals remain shorted. The unit will not attempt to
heat or cool while the terminals remain shorted. Once the status code is
read, power down the unit and remove the short.
Variable Speed Compressor Winding Resistance
This compressor operates with 3-phase variable frequency PWM
variable voltage. For troubleshooting fault codes related to compressor
resistances, follow these steps:
1. Disconnect compressor power leads from the inverter MOC
terminals, U (YEL), V (RED), and W (BLK).
2. Measure the resistance between YEL to RED, YEL to BLK, and
RED to BLK and compare to Table 7 values. Each resistance set
should be equal.
3. Measure the resistance to ground for each lead.
4. If the resistances check out, reconnect power leads to appropriate
terminal.
5. If the resistances appear to be abnormal, it will be necessary to
measure the resistance at the compressor fusite terminals.
6. During the removal of the compressor fusite cap, do not remove the
RTV sealant. Remove the harness plug, measure resistances, and
compare to Table 7.
7. Special care will need to be taken with the replacement of the
compressor fusite cap. Make sure the two holes in the compressor
fusite terminal box are still full of RTV sealant before the cap is
reinstalled. The factory RTV can be reused as long as none of it has
been removed during the cap removal.
8. Reinstall compressor sound blanket making sure discharge
thermistor and compressor power harness are routed as they were
from the factory
Fan Motor
If verification of proper operation is required for the fan motor used in
this unit, follow these steps:
1. Disconnect fan motor connector from control board.
2. Measure resistance between any 2 of the 3 leads present.
3. Compare measurement to values Table 8.
IMPORTANT: Occasionally the unit may become unresponsive due to
certain combinations of previous fault codes. There may not be anything
wrong with the unit or components. The unit may require a high voltage
power cycling for at least 2 minutes or longer to clear the condition. If
the condition persists, conduct further troubleshooting per the service
manual.
Control Fault
If the outdoor unit control board has failed, the control will flash the
appropriate fault code (see Table 10). The control board should be
replaced.
Brown-Out Protection
If the line voltage is less than 187V for at least 4 seconds, the
Compressor and OD fan goes to 0 rpm. Compressor and fan operation
are not allowed until voltage is a minimum of 190V. The control will
flash the appropriate fault code (see Table 10).
230V Line (Power Disconnect) Detection
The control board senses the presence of absence of 230V through
inverter feedback. Voltage should present at all times when system is in
service regardless if system is running or standby. If there is no 230V at
the inverter when the indoor unit is powered with a cooling or heating
demand, the appropriate fault code is displayed on WC (communicating
only – see Fig. 31). If system is configured with conventional heat pump
thermostat (non-communicating), no fault code will be displayed on
AOC board, nor will any status LEDs be lit. Use multimeter to check for
the presence of 230V in this situation.
CVA9, HVA9,
TVA9 FAST PART
NUMBER
Pins 1-4 (R1) Pins 2-3
(R2)
24 1184942 18K 91K
25 1188023 18K 5.1K
36 1184944 18K 150K
37 1188024 18K 18K
48 1184946 18K 220K
49 1188025 18K 33K
60 1184948 18K 360K
Table 6 – Factory Supplied Model Plug Information (Continued) Table 7 – Variable Speed Compressor Resistance
(winding resistance at 70°F? 20°F)
WINDING
(between)
MODEL *VH8 (Ohms)
24 25 36 37, 48 49 (AC),
60
terminals 1.13
OHM .59 OHM .59 OHM .37 OHM .24 OHM
terminal & ground >1 mega OHM
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage and/or
improper operation.
Do not use Meggar for measuring the winding resistance.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage and/or
improper operation.
To maintain water integrity of the compressor fusite terminal box, the
two holes in outer ring need to be full of RTV sealant.
Table 8 – Fan Motor Resistance
Unit Size Resistance (Ohms)
24 21.2
25, 36, 37, 48, 49 (AC), 60 11.1

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12
High Pressure Switch Protection
The outdoor unit is equipped with high pressure switch. If the control
senses the opening of a high pressure switch (open 600+/-5 psig, close
470+/-10 psig @77°F), it will respond as follows:
1. Display the appropriate fault code (see Fig. 31).
2. After a 6 minute delay, if there is a call for cooling or heating and
HPS is reset, the PEV opens for 150 seconds to equalize system
pressures. Compressor and fan will then ramp to the next lower
stage of operation until demand is satisfied. Staging down and
resetting to the highest stage will end after 2 hours of accumulated
operation without further HPS trips.
3. A system malfunction will occur after repeated HPS faults and the
stage has reached the lowest level. This could take five consecutive
HPS trips if the first occurred in stage 5 demand, or 1 HPS trip if in
stage 1 demand.
4. In the event of a high-pressure switch trip or high-pressure lockout,
check the refrigerant charge, outdoor fan operation, and outdoor
coil (in cooling) for airflow restrictions, or indoor airflow in
heating.
Low Pressure Protection
The outdoor unit is equipped with suction pressure transducer. If suction
pressure drops below 15 psi at any time, or below 33 psi for 5 minutes,
the compressor and fan will stop running and an error code will be
displayed on user interface.
1. If there is still a demand for unit operation after the 15 minute delay
and pressure has increased to >43psi (cooling) and >35psi (heating)
, system will resume operation.
2. If there are three (3) consecutive trips because of suction pressure
dropping below 15 psi, the low pressure switch will lock out
operation for 4 hours. Trip counter will be reset after 15 minutes of
successful operation.
3. When a change in demanded stage occurs, suction pressure is
checked at each stage in between current and demanded stage. This
is to prevent ramping of compressor speed too quickly and creating
a low pressure situation. As long as suction pressure is >=45psi,
the compressor is able to ramp to next stage. If suction pressure is
lower than required, additional wait time at current stage will occur.
4. In the event of a low-pressure trip or low-pressure lockout, check
the refrigerant charge and indoor airflow (cooling) and outdoor fan
operation and outdoor coil in heating.
Suction Pressure Transducer (SPT)
If accuracy of the transducer is questioned, the technician can check it
while it is attached to the AOC board. Connect a gage manifold to the
suction valve gage port fitting.
At the AOC board, with the wire harness receptacle exposing a portion
of the three pins on the AOC board, a DC voltmeter can read the DC
voltage between ground and supply (input) terminal. Ensure that the
input voltage is 5 VDC. Next, read the DC voltage across the ground
and output terminal. Record the output voltage.
The suction pressure that the pressure transducer is reading can be
calculated by taking the output voltage and subtracting 0.5 from it then
taking that difference and multiplying it by 50. Pressure (psig) = 50.0 x
(DCV out - 0.5). For example, if the measured voltage is 3.0 VDC:
50 X (3.0 - 0.5) = 50 X 2.5 = 125 psig. See Fig. 28.
A12035
Fig. 28 – Suction Pressure Transducer (SPT)
Output Function Graph
Temperature Thermistors
Thermistors are electronic devices which sense temperature. As the
temperature increases, the resistance decreases. 10Kohm thermistors are
used to sense outdoor air temperature (OAT), coil temperature (OCT)
and the suction line temperature (OST) located between the reversing
valve and the accumulator. A 50Kohm thermistor is used to sense
discharge temperature (ODT).
Refer to Table 9 and Figs. 29 and 30.
A91431
Fig. 29 – 10K Thermistor Resistance Vs Temperature
Table 9 – 10K/50K Resistance Values vs Temperature
10Kohm °C (°F)
TEMPERATURE RESISTANCE (ohms)
25.0 (77.0) 10.0 + / - 2.3%
0.0 (32.0) 32.6 + / - 3.2%
-28.0 (-18.4) 85.5 + / - 3.4%
50Kohm
125.0 (257.0) 1.7 + / - 1.6%
75.0 (167.0) 7.40 + / - 2.0%
25.0 (77.0) 50.0 + / - 2.3%

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13
A14022
Fig. 30 – 50K Thermistor Resistance Vs Temperature
If the outdoor air or coil thermistor should fail, the control will flash the
appropriate fault code (see Table 10).
The outdoor air thermistor, coil thermistor and suction thermistor should
be factory mounted in the final locations. Check to ensure thermistors
are mounted properly (See Fig. 2 through Fig. 6).
Thermistor Sensor Comparison
The control continuously monitors and compares the outdoor air
temperature sensor and outdoor coil temperature sensor to ensure proper
operating conditions. The comparison is:
• In cooling if the outdoor air sensor indicates ³10°F (³5.6°C) warmer
than the coil sensor (or) the outdoor air sensor indicates ³25°F (³15°C)
cooler than the coil sensor, the sensors are out of range.
• In heating if the outdoor air sensor indicates ³35°F (³19.4°C) warmer
than the coil sensor (or) the outdoor air sensor indicates ³10°F (³5.6°C)
cooler than the coil sensor, the sensors are out of range.
If the sensors are out of range, the control will flash the appropriate fault
code as shown in Table 10.
The thermistor comparisons are not performed during low ambient
cooling or defrost operation.
Failed Thermistor Default Operation
Factory defaults have been provided in the event of failure of outdoor air
thermistor (OAT) and/or outdoor coil thermistor (OCT).
If the OAT sensor should fail, defrost will be initiated based on coil
temperature and time.
If the OCT sensor should fail, defrost will occur at each time interval
during heating operation, but will terminate after 2 minutes.
If there is a thermistor out-of-range error, defrost will occur at each time
interval during heating operation, but will terminate after 2 minutes.
Count the number of short and long flashes to determine the appropriate
flash code. Fig. 31 and Table 10 gives possible causes and actions
related to each error.
Maximum Power Mode - Inverter over Temperature
The outdoor unit is equipped with inverter temperature sensing. If the
inverter senses a temperature above the high threshold limit, it will
respond as follows:
1. Display the local fault code only on the AOC Status LED.
2. The system will continue to run, but attempt to mitigate by speed
reduction.
3. When the system demand is satisfied, the unit will shut down.
4. If the fault is still active on the AOC Status LED, the ODF will
continue to run at 500 rpm until the inverter temperature falls below
the threshold.
5. The compressor will not restart if the fault is still active.
FAULT CODES / DESCRIPTIONS
A170002
Fig. 31 – Fault Code Label

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14
Table 10 – Fault Code Actions
Flash
Code Type AMBER LED DESCRIPTION Reset Time Mode Possible Causes Actions
43 Fault Codes
ON, no
flash Standby
1, pause Variable Capacity
Normal Operation for
communicating
system
1 (2 sec ON), longer
pause (1 second OFF)
Variable Capacity
(Range Cutback)
Speed Limiting for
communicating
systems
1, pause 2-stage ”Low”
Capacity
Low capacity for
non-communicating
2, pause 2-stage ”High”
Capacity
High capacity for
non-communicating
4, pause 2-stage ”Reduced”
Capacity Speed Limiting for non-communicating systems
25 System
Malfunction
INVALID MODEL
PLUG/INVERTER SIZE NA Both
Missing model plug Install the correct model plug
Wrong Model Plug
Installed Verify correct model plug installed
Damaged Model Plug
Check model plug for corrosion or breakage;
replace if necessary. Check Model Plug
resistance per the wiring diagram
Model Plug not fully
engaged on board Align per the silkscreen layout
Incorrect Model Plug
with Inverter Size
Replace plug or inverter with correct size (If model
plug is for 2 Ton but Inverter is 3 Ton, fault code 25
will be shown)
Damaged AOC
control Replace AOC control
31 Fault
HIGH PRESSURE
SWITCH OPEN
(Stage down for each
occurrence, elevates to
fault code 84 when it
occurs while running on
the lowest stage.
Reduced capacity is
cleared when system
has been continuously
running at any stage for
2 hours with
reduced capacity.)
6 Minutes
(then
reduced
stage
operation)
Both Refer to fault code 84
32 Local
LOW PRESSURE TRIP
(Elevates to fault code
83 after 3 occurrences)
6 Minutes Both Refer to fault code 83
33 Local
LOST INVERTER
COMMUNICATIONS
(Occurs after 2
minutes of no
communications
between AOC and MOC)
(Elevates to fault code
48 after 3 consecutive
failures within 20 minute
or 20 minutes continuous
loss of connection)
NA Both Refer to fault code 48

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15
46 Local BROWNOUT EVENT 6 Minutes Both
Low line voltages
Check for line voltage approximately greater
than180V. If voltage less than 180V and if
persistent contact power provider
Bad connection on L1
and L2
Check for connection on line and load side to verify
connection is good.
Inverter not reading
proper voltage
Verify no action issue from the above list then
replace inverter.
48 System
Malfunction
LOST INVERTER
COMMUNICATIONS
(Elevated from fault code
33 after 3
occurrences)
NA Both
Loose/disconnected
harness (Hardness
between AOC (PL20)
and MOC)
Verify good harness connection
Radio or Electrical
noise
System will try to self-mitigate with repeated start
attempts
Possible damage to
inverter change out the Inverter drive
49 Local
COMPRESSOR OVER
CURRENT FAULT
(Elevates to fault code
95 after 5 occurrences)
6 Minutes Both Refer to fault code 95
53 Fault OUTDOOR AIR TEMP
SENSOR FAULT NA Both
Sensor Harness not
connected to AOC
control
Ensure plug is connected to AOC control
Broken or loose
harness wire
Check harness for continuity; see resistance chart
to check resistance at given temperature
Broken or Damaged
Sensor
Check harness for continuity; see resistance chart
to check resistance at given temperature
Hardware damage to
AOC control Replace AOC control
54 Fault SUCTION TEMP
SENSOR FAULT NA Both
Sensor Harness not
connected to AOC
control
Ensure plug is connected to AOC control
Broken or loose
harness wire
Check harness for continuity; see resistance chart
to check resistance at given temperature
Suction Thermistor
improperly attached or
in wrong location
Ensure Sensor is properly attached to the
accumulator entry-tube
Broken or Damaged
Sensor
Check harness for continuity; see resistance chart
to check resistance at given temperature
Hardware damage to
AOC control Replace AOC control
55 Fault COIL TEMP SENSOR
FAULT NA Both
Sensor Harness not
connected to AOC
control
Ensure plug is connected to AOC control
Broken or loose
harness wire
Check harness for continuity; see resistance chart
to check resistance at given temperature
Coil Thermistor not
properly attached or in
wrong location
Ensure Sensor is properly clipped to the
distributor entry-tube
Broken or Damaged
Sensor
Check harness for continuity; see resistance chart
to check resistance at given temperature
Hardware damage to
AOC control Replace AOC control
Table 10 – Fault Code Actions (Continued)
Flash
Code Type AMBER LED DESCRIPTION Reset Time Mode Possible Causes Actions

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16
56 Event
OAT-OCT
THERMISTOR OUT OF
RANGE
NA Cool Heating when
cooling is demanded Check fuse on AOC control
Check wiring between AOC and reversing valve
troubleshoot reversing valve
Inspect outdoor coil for obstructions
Both
Coil Thermistor not
properly attached or in
wrong location
Ensure Sensor is properly clipped to the
distributor entry-tube
Outdoor Ambient
Temperature sensor
improperly installed
(sensor body may be
in contact with sheet
metal)
Properly install OAT sensor
57 Fault SUCTION PRESSURE
SENSOR FAULT NA Both
Sensor Harness not
connected to AOC
control
Ensure plug is connected to AOC control
Broken or loose
harness wire Check harness
Electrical short
destroyed
Transducer
electronics
Compare transducer reading to gage reading at
service valve (see transducer measurement chart);
Check system for electrical shorts and correct;
replace transducer
Heat damage during
brazing
Compare transducer reading to gage reading at
service valve (see transducer measurement chart);
replace transducer
59 Local
DISCHARGE TEMP
OUT OF RANGE
EVENT
(Stage down for each
occurrence, elevates to
fault code 74 after
5 occurrences.
Reduced capacity is
cleared if demand
cycle is satisfied
without ODT reaching
limit, or system has been
continuously
running at any stage for
2 hours with
reduced capacity)
15 Minutes Both Refer to fault code 74
61 Local
FAN INVERTER FAULT
(elevates to fault code 76
after 5 occurrences)
6 Minutes Both
Fan motor failed to
start
Troubleshoot outdoor fan motor & blade and make
sure they are working
Fan motor rotor
misalignment System will attempt to run again
Refer to fault code 76
63 Local
FAN INVERTER
CURRENT FAULT
(elevates to fault code 86
after 5 occurrences)
6 Minutes Both Refer to fault code 86
Table 10 – Fault Code Actions (Continued)
Flash
Code Type AMBER LED DESCRIPTION Reset Time Mode Possible Causes Actions

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17
65 Local
DC VOLTS
LOW - SPEED
LIMITING
NA Both
Caused by other fault
code shut down System will attempt to run again
Low supply line
voltage (< 197 VAC)
Check supply voltage to ODU; if low contact utility
provider
Loose wire in control
box area Loose wire: check for loose wire in ODU
Inverter internal
damage Replace Inverter
66 Event OUTDOOR FAN
DROPPED OUT 6 Minutes Both
MOC is reporting that
fan motor isn’t running Troubleshoot fan motor and make sure it is working
3T Inverter enters test
mode Replace inverter with latest software
67 Event STATOR HEATER
FAULT 6 Minutes Both
There is a demand for
stator heat but MOC
doesn’t detect it
Check compressor winding resistance or
mis-wire of compressor leads at terminals U,V,W
Damaged inverter
generating other
inoperable fault codes
such as 88, 95
Replace Inverter
68 Event 10 MIN STAGE 2
WARMUP DELAY 10 Minutes Both High voltage power cycle No action
69 System
Malfunction
INVERTER/COMPRESS
OR INTERNAL FAULT
(Elevates to this fault
code after 5 hidden
occurrences of itself)
15 Minutes
Cool Overcharged System
Check system sub-cooling to determine charge
status, if high remove charge using Charging Mode
(follow proper charging
procedures)
Heat Overcharged System
Check charge in heating mode per heating check
charge chart. If pressures do not match then pull
out charge, weigh in using heating charge method
Both
Phase
imbalance/compressor
or
inverter mis-wire
Check compressor winding resistance or
mis-wire of compressor leads at terminals U,V,W
Flooded start Troubleshoot EXV & TXV
Inverter damage Replace inverter
Compressor damage Replace compressor
71 Event COMPRESSOR
DROPPED OUT 6 Minutes Both
MOC is reporting that
compressor isn’t
running
Refer to TIC 2015-0017 for more details
3T Inverter enters test
mode Replace inverter with latest software
72 Local
SUCTION OVER
TEMPERATURE EVENT
(elevates to fault code 82
after 3 occurrences)
15 Minutes Both Refer to fault code 82
Table 10 – Fault Code Actions (Continued)
Flash
Code Type AMBER LED DESCRIPTION Reset Time Mode Possible Causes Actions

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18
74 System
Malfunction
DISCHARGE TEMP
OUT OF RANGE
LOCKOUT
(Elevated from fault code
59 after 5
occurrences)
2 Hours
Cool High Load conditions Over charge: Check system charge
Heat
Low Charge or Loss of
Charge at low
ambient heating
conditions
Check charge in heating mode per heating check
charge chart. If pressures do not match then pull
out charge, weigh in using heating charge method
Heat Expansion Device
Restriction
Heating: Trouble shoot EXV (coil, harnesses);
Trouble shoot the TXV
Power Cycle system, is EXV moving on power up
(audible)
Both
Sensor Harness not
connected to AOC
control
Ensure plug is connected to AOC control
Broken or loose
harness wire
Check harness for continuity; see resistance chart
to check resistance at given temperature
Broken or Damaged
Sensor
Check harness for continuity; see resistance chart
to check resistance at given temperature
Indoor Unit Airflow too
low or off
Troubleshoot indoor fan motor and make sure it is
working
Outdoor Unit Airflow
too low or off
Troubleshoot outdoor fan motor and make sure it is
working
Reversing Valve
Bypass or Reversing
Valve not energized
Reversing Valve stuck halfway
Ensure AOC fuse is good
24 VDC in cooling mode
Check harness and connectors
Both Hardware damage to
AOC control Replace AOC control
Both Nuisance fault during
non-operational mode Refer to TIC 2015-0017 for more details
75 Local
MAXIMUM POWER
MODE - TEMP
(Temporary RPM
reduction or stage
lowering will result)
NA
Heat Indoor Airflow too low
or off Check indoor airflow
Both
Outdoor Airflow too low
or off
Check ODU coil for clogging (ice or debris) and
clean if necessary; Troubleshoot ODU fan motor
and make sure it is working
Blocked Inverter Heat
Exchanger (fins)
Check Inverter fins for debris and clean if
necessary
Application violates
guideline Consult Application Guideline for compliance
76 System
Malfunction
FAN INVERTER
LOCKOUT
(Elevated from fault code
61 after 5
occurrences)
2 Hours Both
Fan blade bent/out of
balance
Check outdoor fan blade
Check for ice build up
Fan blade restricted Check outdoor fan blade clearance
Check for ice build up
Fan motor wiring Check outdoor fan motor connectors and
harness
Fan motor Replace outdoor fan motor
Inverter damage Replace inverter
Table 10 – Fault Code Actions (Continued)
Flash
Code Type AMBER LED DESCRIPTION Reset Time Mode Possible Causes Actions

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
19
77 Local
MAXIMUM POWER
MODE - COMP
CURRENT
(Temporary RPM
reduction or stage
lowering will result)
NA
Cool Overcharged System
Check system sub-cooling to determine charge
status, if high remove charge using Charging Mode
(follow proper charging
procedures)
Heat Overcharged System
Check charge in heating mode per heating check
charge chart. If pressures do not match then pull
out charge, weigh in using heating charge method
Both
Compressor is
operating outside the
allowed operational
envelope
Inverter will reduce speed to a lower stage
Incorrect refrigerant
charge Check refrigerant amount
Outdoor Airflow too low
or off
Check ODU coil for clogging (ice or debris) and
clean if necessary; Troubleshoot ODU fan motor
and make sure it is working
Incoming power
supply voltage
Check voltage versus unit rating plate for
allowable range
Loose or incorrect wire
connections
Check incoming power leads and leads to the
compressor plug
79 Local
COMPRESSOR/
INVERTER FAULT
(Elevates to fault code
88 after 5 occurrences)
6 Minutes Both
Compressor fails to
start
System will try to self-mitigate with repeated start
attempts
Refer to fault code 88
82 System
Malfunction
SUCTION OVER TEMP
LOCKOUT
(Elevated from fault code
72 after 3 occurrences)
4 Hours
Cool Undercharged
System
Check system subcooling to determine charge
status, if low add charge using Charging Mode
(follow proper charging procedures)
Cool Uninsulated vapor line Insulate the vapor line
Cool Indoor TXV operation Troubleshoot TXV
Heat Undercharged
System
Check charge in heating mode per heating check
charge chart. If pressures do not match then pull
out charge, weigh in using heating charge method
Heat Outdoor EXV
operation Troubleshoot EXV
Both Reversing valve
bypass Troubleshoot reversing valve
Table 10 – Fault Code Actions (Continued)
Flash
Code Type AMBER LED DESCRIPTION Reset Time Mode Possible Causes Actions

CVH8, HVH8, TVH8, VA9, HVA9, TVA9: APPLICATION GUIDELINE & SERVICE MANUAL
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
20
83 System
Malfunction
LOW PRESSURE
LOCKOUT FOR 4
HOURS
(Elevated from fault code
32 after 3
occurrences)
4 Hours
Cool
Service Valve left
closed (Liquid or
Vapor)
Ensure Service Valves are open
Cool Undercharged
System
Check system sub-cooling to determine charge
status, if low add charge using
Charging Mode (follow proper charging
procedures)
Cool Indoor Airflow too low
or off
Check Indoor for clogging (ice or debris) and clean
or de-ice if necessary; Troubleshoot
Indoor fan motor and make sure it is working; follow
Indoor Airflow troubleshooting instruction
Cool Restriction in Circuits
or Tubing Repair restriction
Heat EXV Malfunction Troubleshoot EXV (see guide below)
Heat
Service Valve left
closed (Liquid
Service Valve)
Ensure Liquid Service Valve is open
Heat Outdoor Airflow too low
or off
Check Outdoor for clogging (ice or debris) and
clean or de-ice if necessary; Troubleshoot Outdoor
fan motor and make sure it is working; follow
Outdoor Airflow troubleshooting
instruction
Heat Undercharged
System
Check charge in heating mode per heating check
charge chart. If pressures do not match then pull
out charge, weigh in using heating charge method
Both Restriction in Filter
Drier
Check for temperature drop across filter drier and
replace if necessary
Both Expansion Device
Restriction
If short lineset (less than 15 ft.) Troubleshoot TXV
(see guide below); replace if necessary
Table 10 – Fault Code Actions (Continued)
Flash
Code Type AMBER LED DESCRIPTION Reset Time Mode Possible Causes Actions