Maytag Amana VZC20 Guide
Service and Troubleshooting
Copyright © 2015-2017, 2020-2021 Goodman Manufacturing Company, L.P.
RS6215002r10
January 2021
®
is a registered trademark of Maytag Corporation or its related companies and is used under license.
All rights reserved.
TABLE OF CONTENTS
IMPORTANT INFORMATION............................................. 2
PRODUCT IDENTIFICATION ............................................ 4
SYSTEM OPERATION....................................................... 6
SERVICING...................................................................... 14
CHECKING VOLTAGE ............................................... 14
CHECKING WIRING ................................................... 14
CHECKNG THERMOSTAT, WIRING ......................... 14
THERMOSTAT AND WIRING..................................... 14
THERMOSTAT COMFORTBRIDGE™ SYSTEM ...... 14
COMFORTBRIDGE™ SYSTEM WIRING ................. 14
CHECKING TRANSFORMER AND CONTROL
CIRCUIT....................................................................... 15
CHECKING HIGH PRESSURE SWITCH .................. 15
CHECKING INDOOR AND OUTDOOR HI/LOW
PRESSURE SENSOR................................................. 15
CHECKING COMPRESSOR ...................................... 16
COMPRESSOR WINDING INSULATION TEST....... 16
GROUND TEST........................................................... 17
TESTING CRANKCASE HEATER (5 TON ONLY).... 17
TESTING TEMPERATURE SENSORS AND EEV
COIL RESISTANCE..................................................... 17
TESTING EEV COIL RESISTANCE .......................... 18
TESTING REVERSING VALVE.................................. 18
MBVC**00AA-1 HEATER CONTROL......................... 18
AVPEC* HEATER CONTROL..................................... 19
REFRIGERATION REPAIR PRACTICE .................... 20
LEAK TESTING (NITROGEN OR NITRO-
GEN-TRACED) ............................................................ 21
EVACUATION .............................................................. 21
CHARGING.................................................................. 22
Pride and workmanship go into every product to provide
our customers with quality products. It is possible, however,
that during its lifetime a product may require service.
Products should be serviced only by a qualied service
technician who is familiar with the safety procedures
required in the repair and who is equipped with the proper
tools, parts, testing instruments and the appropriate service
manual.
Cancer and Reproductive Harm -
www.P65Warnings.ca.gov
0140M00517-A
For service information related to the Bluetooth® Shared
Data Loader BTSDL01 referenced in this manual, please
refer to the installation instructions for the BTSDL01 at
www.coolcloudhvac.com/loaderuserguide.
IMPORTANT INFORMATION
2
Pride and workmanship go into every product to provide our
customers with quality products. It is possible, however, that
during its lifetime a product may require service. Products
should be serviced only by a qualied service technician who
is familiar with the safety procedures required in the repair
and who is equipped with the proper tools, parts, testing in-
struments and the appropriate service manual.
OUTSIDE THE U.S., .
(Not a technical assistance line for dealers.) Your telephone company will bill you for the call.
HIGH VOLTAGE !
D
ISCONNECT ALL POWER BEFORE SERVICING.
MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE
TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL
INJURY OR DEATH.
D
O
NOT
CONNECT
TO
OR
USE
ANY
DEVICE
THAT
IS
NOT
DESIGN
CERTIFIED
BY
THE
MANUFACTURER
FOR
USE
WITH
THIS
UNIT
. S
ERIOUS
PROPERTY
DAMAGE
,
PERSONAL
INJURY
,
REDUCED
UNIT
PERFORMANCE
AND
/
OR
HAZARDOUS
CONDITIONS
MAY
RESULT
FROM
THE
USE
OF
SUCH
NON
-
APPROVED
DEVICES
.
While these items will not cover every conceivable situa-
tion, they should serve as a useful guide.
REFRIGERANTS ARE HEAVIER THAN AIR. THEY CAN “PUSH OUT” THE
OXYGEN IN YOUR LUNGS OR IN ANY ENCLOSED SPACE. TOAVOID
POSSIBLE DIFFICULTY IN BREATHING OR DEATH:
• NEVER PURGE REFRIGERANT INTO AN ENCLOSED ROOM OR SPACE. BY
LAW, ALL REFRIGERANTS MUST BE RECLAIMED.
• IFAN INDOOR LEAK IS SUSPECTED, THOROUGHLY VENTILATE THE AREA
BEFORE BEGINNING WORK.
• LIQUID REFRIGERANT CAN BE VERY COLD. TOAVOID POSSIBLE FROST BITE
OR BLINDNESS, AVOID CONTACT AND WEAR GLOVES AND GOGGLES. IF
LIQUID REFRIGERANT DOES CONTACT YOUR SKIN OR EYES, SEEK MEDICAL
HELP IMMEDIATELY.
• ALWAYS FOLLOW EPA REGULATIONS. NEVER BURN REFRIGERANT, AS
POISONOUS GAS WILL BE PRODUCED.
THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY (”EPA”)
HAS ISSUED VARIOUS REGULATIONS REGARDING THE INTRODUCTION
AND DISPOSAL OF REFRIGERANTS INTRODUCED INTO THIS UNIT.
FAILURE TO FOLLOW THESE REGULATIONS MAY HARM THE
ENVIRONMENT AND CAN LEAD TO THE IMPOSITION OF SUBSTANTIAL
FINES. THESE REGULATIONS MAY VARY BY JURISDICTION. SHOULD
QUESTIONS ARISE, CONTACT YOUR LOCAL EPA OFFICE.
TOAVOID POSSIBLE EXPLOSION:
•NEVER APPLY FLAME OR STEAM TO AREFRIGERANT CYLINDER. IFYOU
MUST HEAT ACYLINDER FOR FASTER CHARGING, PARTIALLY IMMERSE
IT IN WARM WATER.
•NEVER FILL ACYLINDER MORE THAN 80% FULL OF LIQUID
REFRIGERANT.
•NEVER ADD ANYTHING OTHER THAN R-410A TO ARETURNABLE
R-410A CYLINDER. THE SERVICE EQUIPMENT USED MUST BE LISTED
OR CERTIFIED FOR THE TYPE OF REFRIGERANT USE.
•STORE CYLINDERS IN ACOOL, DRY PLACE. NEVER USE ACYLINDER
AS APLATFORM OR AROLLER.
CHECKING COMPRESSOR EFFICIENCY .............. 23
THERMOSTATIC EXPANSION VALVE ..................... 23
OVERFEEDING........................................................... 23
UNDERFEEDING........................................................ 23
SUPREHEAT ............................................................... 23
CECKING SUBCOOLING........................................... 24
CHECKING THERMOSTATIC EXPANSION VALVE
OPERATION ................................................................ 25
NON-CONDENSABLES.............................................. 25
COMPRESSOR BURNOUT ....................................... 25
REFRIGERANT PIPING ............................................. 26
DUCT STATIC PRESSURES AND/OR STATIC PRES-
SURE DROP ACROSS COILS................................... 30
AIR HANDLER EXTERNAL STATIC.......................... 30
COIL STATIC PRESSURE DROP.............................. 30
INDOOR UNIT TROUBLESHOOTING ...................... 32
HEAT PUMP ADVANCE FEATURE MENU ............... 48
EMERGENCY MODE.................................................. 51
SETTING THE MODE DISPLAY - OUTDOOR UNIT 56
CTK04 ADDENDUM .................................................... 65
TROUBLESHOOTING ..................................................... 95
WIRING DIAGRAMS...................................................... 110
ACCESSORIES.............................................................. 114
T
O
PREVENT
THE
RISK
OF
PROPERTY
DAMAGE
,
PERSONAL
INJURY
,
OR
DEATH
,
DO
NOT
STORE
COMBUSTIBLE
MATERIALS
OR
USE
GASOLINE
OR
OTHER
FLAMMABLE
LIQUIDS
OR
VAPORS
IN
THE
VICINITY
OF
THIS
APPLIANCE
.
IMPORTANT INFORMATION
3
T
O
AVOID
POSSIBLE
INJURY
,
EXPLOSION
OR
DEATH
,
PRACTICE
SAFE
HANDLING
OF
REFRIGERANTS
.
THE COMPRESSOR PVE OIL FOR R-410A UNITS IS EXTREMELY
SUSCEPTIBLE TO MOISTURE ABSORPTION AND COULD CAUSE
COMPRESSOR FAILURE. DONOT LEAVE SYSTEM OPEN TO ATMOSPHERE
ANY LONGER THAN NECESSARY FOR INSTALLATION.
SYSTEM CONTAMINANTS, IMPROPER SERVICE PROCEDURE AND/OR
PHYSICAL ABUSE AFFECTING HERMETIC COMPRESSOR ELECTRICAL
TERMINALS MAY CAUSE DANGEROUS SYSTEM VENTING.
Notice:
When the outdoor unit is connected to main power, the
inverter board has a small current owing into it to be pre-
pared for operation when needed. Due to this, the Control
Board components have to be cooled even when the unit is
not running. For this cooling operation, the condenser fan
may come on at any time, including in the winter months.
Any obstruction to the outdoor fan should be avoided at all
times when the unit is powered to prevent damage.
The successful development of hermetically sealed refrig-
eration compressors has completely sealed the compres-
sor’s moving parts and electric motor inside a common
housing, minimizing refrigerant leaks and the hazards
sometimes associated with moving belts, pulleys or cou-
plings.
Fundamental to the design of hermetic compressors is
a method whereby electrical current is transmitted to the
compressor motor through terminal conductors which pass
through the compressor housing wall. These terminals are
sealed in a dielectric material which insulates them from
the housing and maintains the pressure tight integrity of
the hermetic compressor. The terminals and their dielectric
embedment are strongly constructed, but are vulnerable
to careless compressor installation or maintenance pro-
cedures and equally vulnerable to internal electrical short
circuits caused by excessive system contaminants.
In either of these instances, an electrical short between the
terminal and the compressor housing may result in the loss
of integrity between the terminal and its dielectric embed-
ment. This loss may cause the terminals to be expelled,
thereby venting the vaporous and liquid contents of the
compressor housing and system.
A venting compressor terminal normally presents no dan-
ger to anyone, providing the terminal protective cover is
properly in place.
If, however, the terminal protective cover is not properly in
place, a venting terminal may discharge a combination of
(a) hot lubricating oil and refrigerant
(b) ammable mixture (if system is contaminated with air)
in a stream of spray which may be dangerous to anyone in
the vicinity. Death or serious bodily injury could occur.
Under no circumstances is a hermetic compressor to be
electrically energized and/or operated without having the
terminal protective cover properly in place.
See Service Section for proper servicing.
T
O
AVOID
POSSIBLE
EXPLOSION
:
•U
SE
ONLY
RETURNABLE
(
NOT
DISPOSABLE
)
SERVICE
CYLINDERS
WHEN
REMOVING
REFRIGERANT
FROM
A
SYSTEM
.
•E
NSURE
THE
CYLINDER
IS
FREE
OF
DAMAGE
WHICH
COULD
LEAD
TO
A
LEAK
OR
EXPLOSION
.
•E
NSURE
THE
HYDROSTATIC
TEST
DATE
DOES
NOT
EXCEED
5
YEARS
.
•E
NSURE
THE
PRESSURE
RATING
MEETS
OR
EXCEEDS
400
LBS
.
W
HEN
IN
DOUBT
,
DO
NOT
USE
THE
CYLINDER
.
PRODUCT IDENTIFICATION
4
A V Z C 20 036 1 AA
1 2 3 4 5,6 7,8,9 10 11,12
Brand Engineering *
A Amana® Brand Major/ Minor Revisions
* Not used for order or inventory control
Product Category
S Split System Electrical
V Inverter Split System 1- 208/230 V, 1 Phase, 60 Hz
Unit Type Capacity
X Condenser R-410A 024 2 Tons 048 4 Tons
Z Heat Pump R-410A 036 3 Tons 060 5 Tons
C 16 16 SEER 18 18 SEER 20 20 SEER
Communica�on Feature
Integrated communica�ng ComfortBridge™ Technology
Efficiency
G V Z C 20 036 1 AA
1 2 3 4 5,6 7,8,9 10 11,12
Brand Engineering *
G Goodman® Brand Major/ Minor Revisions
* Not used for order or inventory control
Product Category
S Split System Electrical
V Inverter Split System 1- 208/230 V, 1 Phase, 60 Hz
Unit Type Capacity
X Condenser R-410A 024 2 Tons 048 4 Tons
Z Heat Pump R-410A 036 3 Tons
C 16 16 SEER 18 18 SEER 20 20 SEER
Communica�on Feature
Integrated communica�ng ComfortBridge™ Technology
Efficiency
PRODUCT IDENTIFICATION
5
A V P E C 25 B 1 4 AA
123456,78 9 10 11,12
Brand Engineering*
ASingle-Piece Air Handler Major/Minor Revisions
*Notused for inventory management
Unit Applica�on Refrigerant Charge
R 4 = R-410A
S
VElectrical
1208/230V, 1 Phase, 60 Hz
Cabinet Finish Cabinet Width
UUnpainted B = 17½"
P Painted "12=C
D= 24½"
Expansion Device
EElectronic Expansion Valve Nominal Capacity @ 13 SEER
T Expansion Device 24 = 2 Tons31 = 2½ Tons48 = 4 Tons
V Inverter Tuned Expansion Valve 25 = 2 Tons36 = 3 Tons 49 =3-3½ Tons
29 = 2 Tons37 = 3½ Tons59 = 4-5 Tons
Communica�ons30 = 2½ Tons42 = 3½ Tons60 = 5 Tons
C = ComfortNet™ Compa�ble 61 = 4-5 Tons
Mul� Posi�on PSC Motor
Mul� Posi�on EEM Motor
Mul� Posi�on Variable-Speed
Motor - Communica�ng
SYSTEM OPERATION
6
This section gives a basic description of heat pump con-
denser unit operation, its various components and their
basic operation. Ensure your system is properly sized for
heat gain and loss according to methods of the Air Condi-
tioning Contractors Association (ACCA) or equivalent.
The ambient air is pulled through the heat pump con-
denser coil by a direct drive propeller fan. This air is then
discharged out of the top of the cabinet. These units are
designed for free air discharge, so no additional resistance,
like duct work, shall be attached.
The gas and liquid line connections on present models are
of the sweat type for eld piping with refrigerant type cop-
per. Front seating valves are factory installed to accept the
eld run copper. The total refrigerant charge for a normal
installation is factory installed in the heat pump condenser
unit.
*VZC20 models are available in 2 through 5 ton sizes and
use R-410A refrigerant. They are designed for 208/230 volt
single phase applications.
*VZC20 R-410A model units use a Daikin rotary compres-
sor. These models are ComfortBridge™ and ComfortNet™
ready.
There are a number of design characteristics which are
dierent from the traditional compressors.
*VZC20 models use “FVC50K” which is NOT compatible
with mineral oil based lubricants like 3GS. “FVC50K” oil
(required by the manufacturer) must be used if additional oil
is required.
NOTE: For models *VZC200601A* or earlier, use a Daikin
Scroll compressor “FVC68D” oil”
The refrigerant used in the system is R-410A. It is a clear,
colorless, non-toxic and non-irritating liquid. R-410A is a
50:50 blend of R-32 and R-125. The boiling point at atmo-
spheric pressure is -62.9°F.
A few of the important principles that make the refrigeration
cycle possible are: heat always ows from a warmer to a
cooler body. Under lower pressure, a refrigerant will absorb
heat and vaporize at a low temperature. The vapors may
be drawn o and condensed at a higher pressure and tem-
perature to be used again.
The indoor evaporator coil functions to cool and dehumidify
the air conditioned spaces through the evaporative process
taking place within the coil tubes.
NOTE: The pressures and temperatures shown in the
refrigerant cycle illustrations on the following pages are
for demonstration purposes only. Actual temperatures and
pressures are to be obtained from the “Expanded Perfor-
mance Chart”.
Liquid refrigerant at condensing pressure and temperatures
leaves the outdoor condensing coil through the drier and is
metered into the indoor coil through the metering device.
As the cool, low pressure, saturated refrigerant enters the
tubes of the indoor coil, a portion of the liquid immediately
vaporizes. It continues to soak up heat and vaporizes as it
proceeds through the coil, cooling the indoor coil down to
about 48°F.
Heat is continually being transferred to the cool ns and
tubes of the indoor evaporator coil by the warm system air.
This warming process causes the refrigerant to boil. The
heat removed from the air is carried o by the vapor.
As the vapor passes through the last tubes of the coil, it
becomes superheated. That is, it absorbs more heat than is
necessary to vaporize it. This is assurance that only dry gas
will reach the compressor. Liquid reaching the compressor
can weaken or break compressor valves.
The compressor increases the pressure of the gas, thus
adding more heat, and discharges hot, high pressure super-
heated gas into the outdoor condenser coil.
In the condenser coil, the hot refrigerant gas, being warmer
than the outdoor air, rst loses its superheat by heat trans-
ferred from the gas through the tubes and ns of the coil.
The refrigerant now becomes saturated, part liquid, part va-
por and then continues to give up heat until it condenses to
a liquid alone. Once the vapor is fully liqueed, it continues
to give up heat which subcools the liquid, and it is ready to
repeat the cycle.
The inverter system can stop the compressor or outdoor
fan to protect the unit. The inverter system can run higher
compressor speed than required from thermostat to recover
compressor oil that ows.
The heating portion of the refrigeration cycle is similar to the
cooling cycle. By de-energizing the reversing valve solenoid
coil, the ow of the refrigerant is reversed. The indoor coil
now becomes the heat pump condenser coil, and the out-
door coil becomes the evaporator coil. The check valve at
the outdoor coil will be forced closed by the refrigerant ow,
thereby utilizing the outdoor expansion device. An electron-
ic expansion valve meters the condensed refrigerant to the
outdoor coil.
SYSTEM OPERATION
7
The defrosting of the outdoor coil is controlled by the
Control Board and the outdoor coil temperature thermistor
and defrost sensor. The outdoor coil temperature thermis-
tor (Tm) sensor is clamped to a return bend entering the
outdoor coil and the defrost sensor at bottom owrator
leg at outdoor coil outlet. Defrost timing periods of 30, 60,
90 or 120 minutes may be selected via the thermostat
setting. Control Board will initiate time defrost at the in-
terval selected from the thermostat. During operation, the
microprocessor on the Control Board checks the two coil
and defrost temperature (Tm and Tb) via sensors every 5
seconds in heating mode. When the Control Board detects
the coil temperature to be high enough (approximately 54
°F) and defrost sensor more than 43 °F for 30 seconds, the
defrost cycle is terminated and the timing period is reset.
The eld service personnel can also advance a heat pump
to the defrost cycle by selecting “force defrost” option from
thermostat.
A system verication test is now required to check the
equipment settings and functionality.
Inverter units are tested by any of the following methods:
• setting the “SUt” menu (System verication test) to
ON through the indoor unit control board push but-
tons.
• setting the System verication test menu of mode dis-
play screen-4 to ON through the outdoor unit control
board push buttons.
• Through the CoolCloud HVAC phone application.
Once selected, it checks the equipment for approximately 5
- 15 minutes. System test may exceed 15 minutes if there is
an error. Refer to the Troubleshooting section, if error code
appears.
Before starting the SYSTEM TEST, turn o the electric
heater and gas furnace.
NOTE: If the unit is attempting to run SYSTEM TEST in
under 20°F ambient temperature, the unit may not be able
to complete the test due to low suction pressure. In such a
case, re-run the SYSTEM TEST when the ambient tem-
perature exceeds 20° F.
The CoolCloud HVAC phone application designed to im-
prove the contractor’s setup /diagnostic experience.
This application can only use with the ComfortBridge com-
patible indoor unit and can download through CoolCloud
website at https://www.coolcloudhvac.com, Google Play or
the Apple App Store.
Users can see specic model information, review active
diagnostic error codes, observe system status during oper-
ation, make system menu adjustments, add site visit notes
and run system testing of all operational modes (heat / cool
/ fan) directly from the phone.
The phone application is also capable of directly updating
the ComfortBridge compatible indoor unit software anytime
updates are available.
The application will automatically notify the user if updates
are available.
NOTE: The software update may take up to 20 minutes to
complete.
If Installing with a CTK04 thermostat, please see the
addendum for further instructions.
CHARGE mode allows for charging of the system.
System operates for a duration of approximately one hour
while the equipment runs at full capacity.
After one hour, the CHARGE MODE ends and the system
resumes normal operation.
Before starting the CHARGE MODE, turn o the Cool or
Heat mode and electric heater or gas furnace.
a. Inverter units are charged by any of the following meth-
ods:
• setting the “CR9” menu (Charge Mode) to ON through
the indoor unit control board push buttons.
• setting the Charge mode menu of mode display
screen-4 to ON through the outdoor unit control board
push buttons.
• Through the CoolCloud HVAC phone application.
b. The System will remain in charge mode (high speed) for
60 minutes before timing out.
c. When charge mode once complete, the installer must
manually shut o.
If Installing with a CTK04 thermostat, please see the adden-
dum for further instructions.
SYSTEM OPERATION
8
BOOST MODE can be enabled or disabled through the
control board push buttons or through the CoolCloud app.
BOOST MODE allows the system to operate at increased
compressor speed to satisfy unusual high loads. BOOST
MODE is initiated by an outdoor temperature sensor located
in the outdoor unit.
Please note that outdoor equipment operational sound
levels may increase while the equipment is running in
BOOST MODE. Disabling BOOST MODE will provide the
quietest and most ecient operation.
NOTE: BOOST MODE is applicable only for *VZC200**1AB
or later revision.
BOOST MODE is ON by default and is activated when the
outdoor temperature reaches 105°F. BOOST MODE can be
disabled and enabled and the activation temperature
adjusted in the Settings menu of the CoolCloud app or
through the indoor / outdoor push button menus.
If Installing with a CTK04 thermostat, please see the
addendum for further instructions.
The thermostat reads the indoor humidity level and allows
the user to set a dehumidication target based on these
settings. The thermostat controls the humidity level of the
conditioned space using the cooling system. Dehumidica-
tion is engaged whenever a cooling demand is present and
structural humidity levels are above the target level. When
this condition exists, the circulating fan output is reduced,
increasing system run time, over cooling the evaporator coil
and ultimately removing more humidity from the structure
than if only in cooling mode. The thermostat also allows for
an additional overcooling limit setting from 0°F to 3°F
setup. This allows the cooling system to further reduce
humidity by lowering the temperature up to 3°F below the
cooling setpoint in an attempt to better achieve desired
humidity levels.
For eective dehumidication operation:
• Ensure “Dehumidication” is not set to “OFF”
• Verify the cooling airow prole (cool proles) is set to
“Prole D”.
- See the Cool Set-up section of the InstallatioN
Manual for complete airow prole details.
- By default, “dehumidication selection” is stan-
dard and the cooling airow prole is set to
“ProleD”
• For additional dehumidication control, airow settings
are eld adjustable and can be ne-tuned to a value
that is comfortable for the application from a range of
Cool Airow Trim.
• In addition, the system can have Enhanced
Dehumidication operation in setting “A”, “B”, or “C” of
dehumidication based on dehumidication demand.
- See the Dehumidication Select section for more detail.
*The specication of *VZC200241AF, 0361AE,
0481AE, and 0601AE or earlier models are dierent
from this specication. For details, see the
Installation Manual or Service Manual that matches
the Major and Minor revision of the model name.
The ComfortBridge based inverter heating and air
conditioning system uses an indoor unit and outdoor unit
digitally communicating with one another via a two-way
communications path.
The 24 VAC single-stage thermostat sends commands to
the indoor and outdoor units.
The indoor and outdoor units interacting with one another
directly while taking simple analog commands from the
thermostat are the core of unlocking the benets and fea-
tures of the ComfortBridge control system.
NOTE: It is strongly recommend the use of thermostat with
humidity sensor and dehumidication terminal.
Without these functions, Dehumidication operation does
not work.
The ComfortBridge system permits access to additional
system information, advanced set-up features, and ad-
vanced diagnostic/troubleshooting features via the control
board push buttons or the CoolCloud mobile app.
(If using a CTK04 thermostat, please see the addendum for
further instructions.)
The heat pump’s diagnostics menu provides access to the
most recent faults. The six most recent faults can be ac-
cessed through the control board seven segment displays
or the CoolCloud mobile app. Any consecutively repeated
fault is stored a maximum of three times.
Example: A leak in the system, low refrigerant charge or an
incompletely open stop valve can cause the unit to ash
error code E15. This error code suggests that the unit is
experiencing operation at low pressure. The control will only
store this fault the rst three consecutive times the fault
occurs.
NOTE: The fault list can be cleared after performing
maintenance or servicing the system to assist in the
troubleshooting process.
SYSTEM OPERATION
9
This menu displays information about the systems current
status. This menu can be utilized to conrm correct func-
tionality of the equipment and for troubleshooting purposes.
The following items will be displayed:
• Heat Capacity Request Percentage
• Cool Capacity Request Percentage
• Heat Capacity Request During Defrost Percentage
• Dehumidication Request Percentage
• Reversing Valve Status
• Reported Airow by Indoor Unit
• Boost Mode
• Previous Defrost Run Time
The following sensor items will be displayed:
• Outdoor Temperature
• Coil Temperature
• Liquid Line Temperature
• Discharge Temperature
• Defrost Sensor
• Suction Pressure
This function can be enabled this menu.
Please follow the following sequence to enter PUMP
DOWN to accumulate the refrigerant to outdoor unit by 7
Segment Mode. Do not operate COOL ON or HEAT ON
mode to enter PUMP DOWN.
Before starting the PUMP DOWN operation, change indoor
fan trim, delay and prole back to default and stop elec-
tric heater and gas furnace. Remove if no trim feature. In
this operation, the gas and liquid service valve should be
opened.
1. Set 7-segment display to SCREEN 4 (SETTING MODE
2) Setting No. 8 and change the display from “-01” to
“-00” System will then automatically start PUMP DOWN
operation. For information on how to set 7-segment
display, see the section SETTING THE MODE DISPLAY
in this manual.
2. Approximately one minute later, the compressor should
start operating. Check the amperage at the compressor
wiring to see the compressor operation status. Unit dis-
play error code E11 (System verication Test) once the
PUMP DOWN operations starts.
3. Close liquid service valve approximately two minutes
after compressor has come on.
4. Compressor will come to a stop automatically. Close the
suction service valve immediately after the compressor
stops. After completion of PUMP DOWN, unit shows
error code“E11”.
NOTE: Refrigerant cannot be collected to the outdoor unit
completely if the system is overcharged or if there is a delay
in closing the liquid service valve and suction service valve.
Evacuate the left over refrigerant from the system using a
recovery machine.
The mandatory system verication test is enabled from this
menu, which enables a functional check of the equipment,
in addition to ensuring proper stop valve position.
The system allows for the adjustment of several cooling
performance variables. Cool Airow Trim (*1), Cool Airow
Proles, Cool Fan ON Delay, Cool Fan OFF Delay and
Dehumidication Select (some enable option or o ) can be
adjusted in this menu. You can also reset this entire menu
to factory default settings.
See the fol-lowing images showing the four cooling airow
proles.
• Prole A provides only an OFF delay of one (1) minute
at 100% of the cooling demand airow.
• Prole B ramps up to full cooling demand airow by
rst stepping up to 50% of the full demand for 30 sec-
onds. The motor then ramps to 100% of the required
airow. A one (1) minute OFF delay at 100% of the
cooling airow.
• Prole C ramps up to 82% of the full cooling demand
airow and operates there for approximately 7 1/2
minutes. The motor then steps up to the full demand
airow. Prole C also has a one (1) minute 100%
OFF delay.
SYSTEM OPERATION
10
• Prole D (default) ramps up to 50% of the demand
for 1/2 minute, then ramps to 82% of the full cooling
demand airow and operates there for approximately
7 1/2 minutes. The motor then steps up to the full
demand airow. Prole D has a 1/2 minute at 50%
airow OFF delay.
This menu allows for the adjustment of several heating
performance variables. Heat Airow trim (*1), Heat Fan ON
Delay, Heat Fan OFF Delay and timed Defrost interval can
be adjusted in this menu. Time interval of 30, 60, 90 and
120 minutes between two defrost cycles can be set to suit
the weather conditions and performance of the unit.
User can change the airow trim at high, intermediate and
low for cooling and heat pump heating mode.
Select:
Cool/Heat Airow Trim (High): high speed cooling/heating
Cool/Heat Airow Trim (Int): intermediate speed cooling/
heating Cool/Heat Airow Trim (Low): low speed cooling/
heating Under each trim setting, the airow can be in-
creased or decreased by a certain percentage.
*1
1) At Cool and Heat Hi speed trim, *VZC200601* with
**VC960804C, **VM970804C and *MVC800804C com-
bination trim more than 5% settings are invalid. Trimmed
up CFM makes miss matching error.
2) At Cool Hi speed trim, Other than the above, depending
on the connected indoor unit, there are restrictions on
the positive side Trim setting.
If you want to change the Cool Airow Trim to positive
side, be sure to conrm the Airow Trim restrictions in
the latest indoor unit installation manual. The latest
manual can be obtained from the website “Partner-
Link(InfoFinderPlus/ Literature)”.
[PartnerLink URL]
https://partnerlinkmarketing.goodmanmfg.com/goodman/
info-nder-plus
3) At Cool Intermediate and Low speed trim, The Inverter
system uses lower compressor speed and lower indoor
unit CFM to optimize system performance. To obtain
100% CFM for home circulation, use full Trim setting
instead of Int/Low speed. This is recommended for ap-
plications with unusually cold return temperatures such
as basements.
When Dehumidication mode exists, the circulating fan out-
put is reduced, increasing system run time, over cooling the
evaporator coil and ultimately removing more humidity from
the structure than if only in cooling mode.
The system can have Dehumidication operation in setting
“Standard”, “A”, “B” or “C” of “dehumidify with cooling” menu
based on dehumidication demand.
Setting “Standard” allows for the widest compressor opera-
tion range with lower CFM than Cooling mode.
In the Enhanced Dehumidication (setting A, B and C)
the indoor airow is lower than Standard Dehumidication
(Standard).
Setting “A” allows for the same compressor operation range
in Dehumidication operation with lower CFM than standard
dehumidication (Standard).
Setting “B” limits compressor operation range and keeps
high dehumidication capacity.
In setting “C” the system runs xed at 100% compressor
and airow. See Figure 1.
NOTE: In high humidity environments, sweating on supply
ducts, cased coils or air handler cabinets can become an
issue in Enhanced Dehumidication operation. It is strongly
recommended covering then with 2” berglass insulation for
these installations.
* The specication of *VZC200241AF, 0361AE, 0481AE
and 0601AE or earlier models are dierent from this
specication.
For details, see the Installation Manual or Service Manual
that matches the Major and Minor revision of model name.
SYSTEM OPERATION
11
(SELECTED RPS/ RPS range)
Max compressor speed at which the outdoor unit will
operate can be changed through the control board seven
segment displays or the CoolCloud mobile app.
Max compressor speed can be changed to get the required
capacity or eciency.
Once the maximum speed is set, the system operates
between the set maximum speed and default low speed.
When determining the appropriate compressor speed for
cooling and heating, in the “RPS Range For Cooling/
Heating” menu select the range that contains the desired
value. (Then, after pressing the Apply Changes button,
leave the Device setting menu and enter this menu again.
Otherwise, the changed settings will not be reected.)
Next, in the “Selected RPS for Cooling/Heating” menu,
select the desired RPS within the displayed range.
SYSTEM OPERATION
12
THE SPECIFICATION OF *VXC200601A OR EARLIER MODELS ARE DIFFERENT FROM THIS SPECIFICATION. FOR DETAILS,SEE THE SERVICE
MANUAL THAT MATCHES THE MAJOR REVISION OF MODEL NAME.
NOTICE
LEGEND:
Tl =Thermisto r( Outdoor Liquid Temperature)
Td =Thermistor(Discharge Temperature )
Ta =Thermistor( Outdoor Air Temperature)
HP/LP sensor= High/Low Pressure Sensor
HPS= High Pressure Switch
Tm =Thermistor(Outdoor Coil Temperature )
Piping Diagram with TX
V a
pplicable indoor unit
Hex
Fan
Motor
Filter
dryer
Stop
Valve
(Liquid)
Ball Valve
(Gas)
Fan
Motor
Hex
HP/LP
HP/LPs ensor
Tm
Thermistor
Ref cooling
Ta Thermistor
Outdooru nit
Indoor unit
TXV
Check
valve
Td Thermistor
Filter
Compressor
Capillaryt ube
HPS
Oil
separator
Accumulator
T Thermistor
Reversing
Valve
Check
valve
EEV
Filter
Filter
SYSTEM OPERATION
13
LEGEND:
Tl =Thermistor(Outdoor Liquid Temperature)
Td =Thermistor(DischargeTemperature)
Ta =Thermistor(Outdoor AirTemperature)
Tm =Thermistor(Outdoor Coil Temperature)
Tli=Thermistor (Indoor Liquid Temperature)
Tgi=Thermistor (Indoor GasTemperature)
ID HP/LPsensor=Indoor High/Low Pressure Sensor
OD HP/LPsensor=Outdoor High/Low Pressure Sensor
HPS=High Pressure Switch
THE SPECIFICATION OF *VXC200601A OR EARLIER MODELS ARE DIFFERENT FROM THIS SPECIFICATION. FOR DETAILS,SEE THE SERVICE
MANUAL THAT MATCHES THE MAJOR REVISION OF MODEL NAME.
NOTICE
SERVICING
14
1. Remove outer case, control panel cover, etc., from unit
being tested.
With power ON:
L
INE
V
OLTAGE
NOW
PRESENT
.
2. Using a voltmeter, measure the voltage across terminals
L1 and L2 of the contactor for the heat pump condens-
er unit or at the eld connections for the air handler or
heaters.
Measure the voltage across the L1 and L2 lugs on the
unitary (UC) control.
3. No reading - indicates open wiring, open fuse(s) no pow-
er or etc., from unit to fused disconnect service. Repair
as needed.
4. With ample voltage at line voltage connectors, energize
the unit.
voltage min. max.
Outdoor Unit, Air Handler,
Modular Blower, Heater Kit 208/230 197 253
Gas Furnaces 115 103 126
Unit Supply Voltage (VAC)
Unit Type
NOTE: When operating electric heaters on voltages other
than 240 volt, refer to the System Operation section on
electric heaters to calculate temperature rise and air ow.
Low voltage may cause insucient heating.
HIGH VOLTAGE !
DISCONNECT ALL POWER BEFORE SERVICING OR
INSTALLING. MULTIPLE POWER SOURCES MAY BE
PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
1. Check wiring visually for signs of overheating, damaged
insulation and loose connections.
2. Use an ohmmeter to check continuity of any suspected
open wires.
3. If any wires must be replaced, replace with comparable
gauge and insulation thickness.
Communicating Thermostat Wiring: The maximum wire
length for 18 AWG thermostat wire is 250 feet.
L
INE
V
OLTAGE
NOW
PRESENT
.
With power ON, thermostat calling for cooling/heating.
1. Use a voltmeter to check for 24 volt at thermostat wires
C and R in the indoor unit control panel.
2. No voltage indicates trouble in the thermostat, wiring or
transformer source.
3. Check the continuity of the thermostat and wiring. Re-
pair or replace as necessary.
L
INE
V
OLTAGE
NOW
PRESENT
.
Resistance Heaters
With power ON:
1. Set room thermostat to a higher setting than room
temperature so both stages call for heat.
2. With voltmeter, check for 24 volt at each heater relay.
3. No voltage indicates the trouble is in the thermostat or
wiring.
4. Check the continuity of the thermostat and wiring.
Repair or replace as necessary.
NOTE: Consideration must be given to how the heaters
are wired (O.D.T. and etc.). Also safety devices must be
checked for continuity.
OVERVIEW
The ComfortBridge based inverter heating and air
conditioning system uses an indoor unit and outdoor unit
digitally communicating with one another via a two-way
communications path.
The 24 VAC single-stage thermostat sends commands to
the indoor and outdoor units.
The indoor and outdoor units interacting with one another
directly while taking simple analog commands from the
thermostat are the core of unlocking the benets and
features of the ComfortBridge control system.
NOTE:
It is recommend the use of thermostat with
humidity sensor and dehumidication terminal.
Without these functions, Dehumidication operation does
not work.
ComfortBridge™ control system is low voltage wiring
consists of two wires between the indoor unit and outdoor
unit.
SERVICING
15
The required wires are data lines 1 and 2.
The thermostat needs 4 wires between the indoor unit and
thermostat or 5 wires if the thermostat requires a Common
wire.
NOTE:
Regarding the wiring of the indoor unit to the thermostat,
also refer to ComfortBridge compatible indoor unit’s Install
manual (in case of communicating inverter system.).
If Installing with a CTK04 thermostat, please see the
addendum for further instructions.”
12 R C
ComfortBridge TM Compable
Air Handler Blower,
Gas Furnace or Module Blower
Integrated Control Module
(*) Allowable Maximum Length
Outdoor unit
Integrated Control Module
250 . (*)
12 R C
SYSTEM WIRING
GW Y DH
Y2
RC
Single-Stage Thermostat(24 VAC )
GW Y De-
hum
RC
:Oponal Wiring
HIGH VOLTAGE !
DISCONNECT ALL POWER BEFORE SERVICING OR
INSTALLING. MULTIPLE POWER SOURCES MAY BE
PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
A step-down transformer (208/230 volt primary to 24 volt
secondary) is provided with each indoor unit. This al-
lows ample capacity for use with resistance heaters. The
outdoor sections do not contain a transformer (see note
below). (see indoor unit WIRING DIAGRAM)
DISCONNECT ALL POWER BEFORE SERVICING.
1. Remove control panel cover, or etc., to gain access to
transformer.
With power ON:
L
INE
V
OLTAGE
NOW
PRESENT
.
2. Using a voltmeter, check voltage across secondary volt-
age side of transformer (R to C).
3. No voltage indicates faulty transformer, bad wiring, or
bad splices.
4. Check transformer primary voltage at incoming line
voltage connections and/or splices.
5. If line voltage available at primary voltage side of
transformer and wiring and splices good, transformer is
inoperative. Replace.
HIGH VOLTAGE !
DISCONNECT ALL POWER BEFORE SERVICING OR
INSTALLING. MULTIPLE POWER SOURCES MAY BE
PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
The high pressure switch senses the pressure in the com-
pressor discharge line. If abnormally high condensing pres-
sures develop, the contacts of the control open, breaking
the control circuit before the compressor motor overloads.
This control is automatically reset.
1. Using an ohmmeter, check across the X32A connection
on outdoor unit PCB high pressure control, with wire
removed. If not continuous, the contacts are open.
2. Attach a gauge to the dill valve port on the base valve.
With power ON:
L
INE
V
OLTAGE
NOW
PRESENT
.
3. Start the system in charge mode and place a piece of
cardboard in front of the outdoor coil, raising the con-
densing pressure.
4. Check pressure at which the high pressure control cuts-
out. If it cuts-out at 605 PSIG to -17 PSIG, it is operating
normally (See causes for high head pressure in Service
Problem Analysis Guide). If it cuts out below this pres-
sure range, replace the control.
The HI/LOW pressure sensor senses the suction pressure
in cooling mode, and the discharge pressure in heating
mode. Follow the following sequence to check the pressure
sensor.
1. Connect manifold gauge to the air conditioner unit
2. Connect a pair of extended Molex probe tips to your
voltmeter test leads.
3. Find the suction pressure in the cool mode, or discharge
pressure in the heat mode (terminals) Locate (X17A)
connection and connect a DC voltmeter across sensor
terminals 1 and 3, (black and white wires) and record the
DC voltage.
SERVICING
16
4. Compare your readings to the detected pressure vs
output voltage in the following table. Replace the sensor
if the sensor is open, shorted, or outside of the voltage
range.
L
INE
V
OLTAGE
NOW
PRESENT
.
-200
-100
0
100
200
300
400
500
600
700
800
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
Detected Pressure (PSIG)
Output Voltage (DCV)
VOLTAGE AND PRESSURE CHARACTERISTICS
If the compressor terminal PROTECTIVE COVER and
gasket (if required) are not properly in place and secured,
there is a remote possibility if a terminal vents, that the
vaporous and liquid discharge can be ignited, spouting
ames several feet, causing potentially severe or fatal injury
to anyone in its path.
This discharge can be ignited external to the compressor if
the terminal cover is not properly in place and if the
discharge impinges on a sucient heat source.
Ignition of the discharge can also occur at the venting
terminal or inside the compressor, if there is sucient
contaminant air present in the system and an electrical arc
occurs as the terminal vents.
Ignition cannot occur at the venting terminal without the
presence of contaminant air, and cannot occur externally
from the venting terminal without the presence of an
external ignition source.
Therefore, proper evacuation of a hermetic system is
essential at the time of manufacture and during servicing.
To reduce the possibility of external ignition, all open ame,
electrical power, and other heat sources should be
extinguished or turned o prior to servicing a system.
The Inverter on the outdoor control board takes the position
signal from the UVW line, connected with the compressor.
If the system detects a malfunction on the compressor,
check the insulation resistance in accordance with the fol-
lowing procedure.
1. Remove the leads from the compressor terminals.
2. Using a Megometer, attach one lead to ground.
3. Using the other lead of the Megometer, check the insula-
tion between U to ground, V to ground, W to ground.
Compressor
Terminal
Unpainted
Refrigerant
Piping
TESTING COMPRESSOR WINDINGS INSULATION
NOTE: The 2, 3, and 4 ton compressor has a terminal on
the top. The 5 ton compressor has the terminals on the
side. If the insulation resistance of the compressor is less
than 100k Ohms between U to ground, V to ground, W to
ground, replace the compressor.
SERVICING
17
NOTE: If an open compressor is indicated, allow ample
time for the internal overload to reset before replacing com-
pressor.
If fuse, circuit breaker, ground fault protective device, etc.,
has tripped, this is a strong indication that an electrical
problem exists and must be found and corrected. The circuit
protective device rating must be checked, and its maximum
rating should coincide with that marked on the equipment
nameplate.
With the terminal protective cover in place, it is acceptable
to replace the fuse or reset the circuit breaker ONE TIME
ONLY to see if it was just a nuisance opening. If it opens
again, DO NOT continue to reset.
Disconnect all power to unit, making sure that all power
legs are open.
1. DO NOT remove protective terminal cover. Disconnect
the three leads going to the compressor terminals at the
nearest point to the compressor.
2. Identify the leads and using an ohmmeter on the R x
10,000 scale or the highest resistance scale on your
ohmmeter check the resistance between each of the
three leads separately to ground (such as an unpainted
tube on the compressor).
3. If a ground is indicated, then carefully remove the com-
pressor terminal protective cover and inspect for loose
leads or insulation breaks in the lead wires.
4. If no visual problems indicated, carefully remove the
leads at the compressor terminals.
5. Carefully retest for ground, directly between compressor
terminals and ground.
6. If ground is indicated, replace the compressor. The resis-
tance reading should be innity. If there is any reading
on meter, there is some continuity to ground and com-
pressor should be considered defective.
OL
The crankcase heater must be energized a minimum of 2
hours before the unit is operated. Crankcase heaters are
used to prevent migration or accumulation of refrigerant in
the compressor crankcase during the o cycles and pre-
vents liquid slugging or oil pumping on start up. A crankcase
heater will not prevent compressor damage due to a ood-
back or over charge condition.
1. Disconnect the heater lead in wires.
2. Using an ohmmeter, check heater continuity - should
test continuous. If not, replace.
NOTE: The positive temperature coecient crankcase
heater is a 33 watt 240 voltage heater. The cool resistance
of the heater will be approximately 1745 ohms. The resis-
tance will become greater as the temperature of the com-
pressor shell increases.
The *VZC20 outdoor units and AVPEC* indoor units are fac-
tory equipped with:
• (Ta) an outdoor air temperature sensor
• (Tm) an outdoor coil temperature sensor
• (TI) an outdoor liquid temperature sensor
• (Td) a discharge temperature sensor
• (Tb) a defrost temperature sensor
• (Tgi) an indoor gas temperature sensor
• (Tli) an indoor liquid temperature sensor
To check above sensors:
1. Disconnect power to the heat pump condensor.
2. Disconnect the sensor from the electric board.
3. Connect an ohmmeter across the sensor terminals. The
ohmmeter should read be the resistance shown in the
table THERMISTOR RESISTANCE AND TEMPERA-
TURE CHARACTERISTICS. Replace the sensor if the
sensor is open, shorted, or outside the valid resistance
range.
SERVICING
18
To check the resistance of the EEV coil, rst disconnect
EEV cable from the Control board. Make measurements of
resistance between the connector pins, and then make sure
the resistance falls in the range of 40 to 50Ω.
Outdoor unit: 2 Ton
Outdoor unit: 3. 4. & 5 Ton
CHECKING REVERSING VALVE AND SOLENOID
Reversing valve used in heat pumps could potentially leak
internally. Discharge gases can leak into the suction inside
the valve. Compound gages will give the same symptoms
as bad compressor valves or broken scroll anks. The
temperature between true suction and the suction line after
the valve should not be greater than 4 degrees. Note: The
center tube is always the suction line and should be cold.
TROUBLESHOOTING THE REVERSING VALVE FOR
ELECTRICAL FAILURE
Place unit into the cooling mode. Test for 24 volts at the
solenoid. If there is no voltage present at coil, check the
control voltage. If voltage is present, loosen the nut on the
top of the coil. Remove the coil, there should be slight resis-
tance. If the slight resistance is felt, remove the coil. As you
remove the coil listen carefully, an audible click should be
detected. The clicking is due to the movement of the pilot
valve plunger. The absence of a clicking sound indicates
the plunger is stuck.
TROUBLESHOOTING MECHANICAL FAILURES ON A
REVERSING VALVE BY PRESSURE
Troubleshooting the reversing valve can be done by pres-
sure and touch. Raise the head pressure. In the cooling
mode block the fan exhaust. Once head pressure has been
raised, cycle between cooling and heating and see if the
piston can be freed.
TROUBLESHOOTING MECHANICAL FAILURES ON A
REVERSING VALVE BY TEMPERATURE
When operating properly the valve contains refrigerant
gases at certain temperatures. The discharge line should be
the same temperature after the valves discharge line.
The true suction should be the same as the suction line
after the valve. If there is a 4-degree dierence, valve is
leaking. When stuck in the mid-position, part of the dis-
charge gas from the compressor is directed back to the
suction side, resulting in excessively high suction pressure.
An increase in the suction line temperature through the
reversing valve can also be measured. Check operation of
the valve by starting the system and switching the opera-
tion from COOLING to HEATING cycle. If the valve fails to
change its position, test the voltage (24V) at the valve coil
terminals (X25A) on outdoor unit PCB while the system is
on the COOLING cycle. If voltage is registered at the coil,
tap the valve body lightly while switching the system from
HEATING to COOLING, etc. If this fails to cause the valve
to switch positions, remove the coil connector cap and test
the continuity of the reversing valve solenoid coil. If the coil
does not test continuous - replace it. If the coil test continu-
ous and 24 volts is present at the coil terminals, the valve is
inoperative - replace it.
DESCRIPTION
The MBVC models utilize an electronic control that provides
ECM blower motor control and control of up to two electric
heat sequencers. The control has thermostat inputs for up
to two stages of cooling, two stages of electric heat, revers-
ing valve, and dehumidication. Control input is 24VAC.
All dipswitches necessary to setup cooling and electric heat
airow are fully integrated into the control.
FEATURES
The new air handler control includes advanced diagnostic
features with fault recall, estimated CFM display via on-
board LED, and ComfortNetTM ready. Diagnostics includes
heater kit selection diagnostics, open fuse, internal control
fault, data errors, and blower motor faults. Data errors are
not included in the fault recall list. Diagnostic error codes
are displayed on a single red LED.
The estimated CFM is displayed on an on-board green
LED. The LED ashes once for each 100 CFM.
The AVPEC air handlers may be used in a fully communi-
cating ComfortNet system when matched with a compatible
outdoor unit and the CTK04 thermostat. A fully communi-
cating system oers advanced setup and diagnostic fea-
tures.
BASIC OPERATION
The air handler control receives thermostat inputs from the
CTK04 ComfortNet thermostat. The control operates the
variable speed blower motor at the demand as determined
from the thermostat input(s). If a demand for electric heat
is received, the control will provide a 24VAC output for up to
two electric heat sequencers.
SERVICING
19
TROUBLESHOOTING
MOTOR CONTROL CIRCUITS
1. Turn on power to air handler or modular.
2. Check voltage between pins 1 and 4 at the 4-wire motor
connector on the control board. Voltage should be
between 9 and 15 VDC. Replace control if voltage is not
as specied.
ELECTRIC HEAT SEQUENCER OUTPUTS
1. Turn on power to air handler or modular blower.
2. Disconnect the 4-circuit harness connecting the control to
the electric heater kit.
3. Provide a thermostat demand for low stage auxiliary
heat. Measure the voltage between pins 1 and 3 at the
onboard electric heat connector. Voltage should mea-
sure 24VAC. Replace control if no voltage is present.
NOTE: Allow for any built-in time delays before making
voltage measurements. Any electric heater faults that are
present may prevent the heater output from energizing. Ver-
ify that no heater faults are present before making voltage
measurements.
4. Provide a thermostat demand for high stage auxiliary
heat (W1 + W2). Measure the voltage between pins 1
and 3 at the on-board electric heat connector. Measure
the voltage between pins 2 and 3 at the on-board electric
heat connector. Voltage should measure 24VAC. Re-
place control if no voltage is present.
Communications (Applies only to Systems with Compatible
ComfortNetTM Outdoor Unit and CTK04AE* Thermostat)
The integrated air handler control has some on-board tools
that may be used to troubleshoot the network. These tools
are: red communications LED, green receive (Rx) LED, and
learn button. These are described below
a. Red communications LED – Indicates the status of the
network. Refer to the Network Troubleshooting Chart for
the LED status and the corresponding potential problem.
b. Green receive LED – Indicates network trac. Refer to
the Network Troubleshooting Chart for the LED status
and the corresponding potential problem.
c. Learn button – Used to reset the network. Depress the
button for approximately 2 seconds to reset the network.
For details, see NETWORK TROUBLSHOOTING section.
DESCRIPTION
The AVPEC* models utilize an electronic control that pro-
vides ECM blower motor control and control of up to two
electric heat sequencers. The control has thermostat inputs
for variable stage of cooling/heating, two stages of electric
heat, reversing valve, and dehumidication. Control input is
24 VAC.
FEATURES
The new air handler control includes advanced diagnostic
features with fault recall, estimated CFM display via 7
segment display of control boad, CoolCloudTM and
ComfortNetTM ready. Diagnostics includes heater kit selec-
tion diagnostics, open fuse, internal control fault, data er-
rors, and blower motor faults. Data errors are not included
in the fault recall list. Diagnostic error codes are displayed
on a single red LED. The estimated CFM is displayed on
an on-board 7 segment display. For example, if the CFM is
1240CFM, 7 segment display shows “FC...A...12...40...”.
The AVPEC* air handlers may be used in a fully communi-
cating system when matched with a compatible outdoor unit
and the thermostat. A fully communicating system oers
advanced setup and diagnostic features.
BASIC OPERATION
The air handler control receives operation demand inputs
from the thermostat. The control operates the variable
speed blower motor at the demand as determined from the
thermostat input(s). If a demand for electric heat is re-
ceived, the control will provide a 24VAC output for up to two
electric heat sequencers.
TROUBLESHOOTING
SERVICING
20
MOTOR CONTROL CIRCUITS
1. Turn on power to air handler or modular.
2. Check voltage between pins 1 and 4 at the 4-wire motor
connector on the control board. Voltage should be be-
tween 9 and 15 VDC. Replace control if voltage is not as
specied.
ELECTRIC HEAT SEQUENCER OUTPUTS
1. Turn on power to air handler or modular blower.
2. Disconnect the 3-circuit harness connecting the control to
the electric heater kit.
3. Provide a thermostat demand for low stage auxiliary heat
(W1). Measure the voltage between pins 1 and 3 at the
on-board electric heat connector. Voltage should mea-
sure 24VAC. Replace control if no voltage is present.
NOTE: Allow for any built-in time delays before making
voltage measurements. Any electric heater faults that are
present may prevent the heater output from energizing.
Verify that no heater faults are present before making volt-
age measurements.
COMMUNICATIONS
The integrated air handler control has some on-board tools
that may be used to troubleshoot the network. These tools
are: red communications LED, green receive (Rx) LED, and
learn button. These are described below
a. Red communications LED – Indicates the status of the
network. Refer to the Network Troubleshooting Chart for
the LED status and the corresponding potential problem.
b. Green receive LED – Indicates network trac. Refer to
the Network Troubleshooting Chart for the LED status
and the corresponding potential problem.
c. Learn button – Used to reset the network. Depress the
button for approximately 2 seconds to reset the network.
For detail see NETWORK TROUBLESHOOTING section.
When repairing the refrigeration system:
1. Never open a system that is under vacuum. Air and
moisture will be drawn in.
2. Plug or cap all openings.
3. Remove all burrs and clean the brazing surfaces of the
tubing with sand cloth or paper. Brazing materials do not
ow well on oxidized or oily surfaces.
4. Clean the inside of all new tubing to remove oils and
pipe chips.
5. When brazing, sweep the tubing with dry nitrogen to
prevent the formation of oxides on the inside surfaces.
6. Complete any repair by replacing the liquid line drier in
the system, evacuate and charge.
BRAZING MATERIALS
Important note: Torch heat required to braze tubes of
various sizes is proportional to the size of the tube. Tubes
of smaller size require less heat to bring the tube to braz-
ing temperature before adding brazing alloy. Applying too
much heat to any tube can melt the tube. Service personnel
must use the appropriate heat level for the size of the tube
being brazed.
NOTE: The use of a heat shield when brazing is recom-
mended to avoid burning the serial plate or the nish on the
unit. Heat trap or wet rags should be used to protect heat
sensitive components such as stop valves, EEV, TXV and
lters.
Copper to Copper Joints - Sil-Fos used without ux (alloy
Other manuals for Amana VZC20
1
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