Carrier Infinity 25HNA6 User manual

®
to the Expert£
Installation Instruction
NOTE: Read the entire instruction manual before starting the
installation.
Unless otherwise noted, information in these installation
instructions pertain to both 25HNA6 and 25HNA9 series units.
Information that is unique to the 25HNA6 series will be identified
as such; likewise information that is unique to the 25HNA9 series
will also be identified.
SAFETY CONSIDERATIONS
Improper installation, adjustment, alteration, service, maintenance,
or use can cause explosion, fire, electrical shock, or other
conditions which may cause death, personal iniury, 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
National Electrical Code (NEC) for special requirements.
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 iniury. 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 iniury
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 iniury or product and
property damage. NOTE is used to highlight suggestions which
will result in enhanced installation, reliability, or operation.
Indoor Thermostat Control Options
Standard
Model Infinity
Control 2-stage
Thermostat
25HNA6 Yes Yes
No
25HNA9 Yes (Emergency
Mode Only)
ELECTRICALSHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Before installing, modifying, or servicing system, main
electrical disconnect switch nmst be in the OFF position
and install a lockout tag. There may be more than 1
disconnect switch. Lock out and tag switch with a
suitable warning label.
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could result in personal iniury
or equipment damage.
Puron® refrigerant systems operate at higher pressures than
standard R-22 systems. Do not use R-22 service equipment
or components on Puron® refrigerant equipment.

INSTALLATIONRECOMMENDATIONS
NOTE:Insomecasesnoiseinthe living area has been traced to
gas pulsations from improper installation of equipment.
1. Locate unit away from windows, patios, decks, etc. where
unit operation sound may disturb customer.
2. Ensure that vapor and liquid tube diameters are appropriate
for unit capacity.
3. Run refrigerant tubes as directly as possible by avoiding un-
necessary turns and bends.
4. Leave some slack between structure and unit to absorb vi-
bration.
5. When passing refrigerant tubes through the wall, seal open-
ing with RTV or other pliable silicon-based caulk. (See Fig.
1.)
6. Avoid direct tubing contact with water pipes, duct work,
floor joists, wall studs, floors, and walls.
7. Do not suspend refrigerant tubing from joists and studs with
a rigid wire or strap which comes in direct contact with
tubing.(See Fig. 1.)
8. Ensure that tubing insulation is pliable and completely sur-
rounds vapor tube.
9. When necessary, use hanger straps which are 1 in. wide and
conform to shape of tubing insulation. (See Fig. 1.)
10. Isolate hanger straps from insulation by using metal sleeves
bent to conform to shape of insulation.
When outdoor unit is connected to factory-approved indoor unit,
outdoor unit contains system refrigerant charge for operation with
ARI rated indoor unit when connected by 15 ft. (4.57 m) of
field-supplied or factory accessory tubing. For proper unit
operation, check refrigerant charge using charging information
located on control box cover and/or in the Check Charge section of
this instruction.
IMPORTANT: Maximum liquid-line size is 3/8-in. OD for all
residential applications including long line applications.
IMPORTANT: Always install the factory-supplied liquid-line
filter drier. Obtain replacement filter driers from your distributor or
branch.
INSTALLATION
NOTEAvoid contact between tubing and structure
OUTDOOR WAJ_._ INDOOR WAL_
CAU L_F-- LIQUID TUBE
SULATI__---_L VAPO R TUBE
THROUGH THE WALL
HANGER STRAP "_ ]j_,,,_JOIST
(AROUND VAPOR X_, -- INSULATION
TUBE_ _k, ]___VAPOR TUBE
b d
1" (25.4 mm) MIN. _ L LIQUID TUBE
SUSPENSION
A94028
Fig. 1 - Connecting Tube Installation
Specifications for this unit in residential new construction market
require the outdoor unit, indoor unit, refrigerant tubing sets,
metering device, and filter drier listed in presale literature. There
can be no deviation. Consult the Service Manual - Air
Conditioners and Heat Pumps Using Puron® Refrigerant to obtain
required unit changes for specific applications and for R-22
retrofit.
Check Equipment and Job Site
Unpack Unit
Move to final location. Remove carton taking care not to damage
unit.
Inspect Equipment
File claim with shipping company prior to installation if shipment
is damaged or incomplete. Locate unit rating plate on unit corner
panel. It contains information needed to properly install unit.
Check rating plate to be sure unit matches job specifications.
Install on a Solid, Level Mounting Pad
If conditions or local codes require the unit be attached to pad, tie
down bolts should be used and fastened through knockouts
provided in unit base pan. Refer to unit mounting pattern in Fig. 2
to deternfine base pan size and knockout hole location.
For hurricane tie downs, contact distributor for details and PE
(Professional Engineer)Certification, if required.
On rooftop applications, mount on level platform or frame. Place
unit above a load-bearing wall and isolate unit and tubing set from
structure. Arrange supporting members to adequately support unit
and nfininfize transnfission of vibration to building. Consult local
codes governing rooftop applications.
Roof mounted units exposed to winds above 5 mph may require
wind baffles. Consult the Service Manual - Residential Split
System Air Conditioners and Heat Pumps Using Puron®
Refrigerant for wind baffle construction.
UNIT BASE PAN
DIMENSIONS
in. (ram)
86-1/2 x 40
(927.1x1016)
TIEDOWN KNOCKOUT LOCATIONS
in. (ram)
ABC
11-5/8 6-13/16 28-8/4
(295.8) (178.0) (780.8)
A05242
Fig. 2 - Tiedown Knockout Locations
NOTE: Unit nmst be level to within -+2° (-+3/8 in./fl. /-+9.53
tuna/m) per compressor manufacturer specifications.
Clearance Requirements
When installing, allow sufficient space for airflow clearance,
wiring, refrigerant piping, and service. Allow 30 in. (762 ram)
clearance to service end of unit and 48 in. (1219.2 ram) above unit.
For proper airflow, a 6 in. (152.4 ram) clearance on 1 side of unit
and 12 in. (304.8 ram) on all remaining sides nmst be maintained.
Maintain a distance of 24 in. (609.6 ram) between units. Position
so water, snow, or ice from roof or eaves cannot fall directly on
unit.
On rooftop applications, locate unit at least 6 in. (152.4 ram) above
roof surface.

Operating Ambient
The minimum outdoor operating ambient in cooling mode is
55°F/12.78°C without low ambient cooling enabled, and the
maximum outdoor operating ambient in cooling mode is
125°F/51.67°C. On Infinity communicating systems only (for
both 25HNA6 and 25HNA9), low ambient cooling is available to
0°F/-17.78°C.
The maximum outdoor operating ambient in heating mode is
66°F/18.89°C on all models.
Elevate Unit
UNIT OPERATION HAZARD
Make Piping Connections
PERSONAL INJURY AND UNIT DAMAGE
HAZARD
Failure to follow this warning could result in personal
injury or death.
Relieve pressure and recover all refrigerant before system
repair or final unit disposal. Use all service ports and open
all flow-control devices, including solenoid valves.
Failure to follow this caution may result in equipment
damage or improper operation.
Do not allow water and/or ice to build up in base pan.
Elevate unit per local climate and code requirements to provide
clearance above estimated snowfall level and ensure adequate
drainage of unit.
UNIT OPERATION HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Locate the unit in such a way that it is stable in all
circumstances including adverse weather conditions.
In Long-Line Applications, Install Liquid-Line
Solenoid Valve (LSV)
For refrigerant piping arrangements with equivalent lengths greater
than 80 ft. (24.38 m) and/or when elevation difference between
indoor and outdoor unit is greater than ---20 ft. (---6.10 m), follow
all requirements of the Long-Line Guideline--Air Conditioners
and Heat Pumps Using Puron® refrigerant. If required by
Long-Line Guideline, install LSV kit, part no. KHALS0401LLS,
specifically designed for Puron® refrigerant heat pumps. LSV
should be installed within 2 ft. (0.61 m) of outdoor unit with flow
arrow pointing toward outdoor unit. Follow the Installation
Instructions included with accessory kit.
IMPORTANT: Flow arrow must point toward outdoor unit.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Do not leave system open to atmosphere any longer than
minimum required for installation. POE oil in compressor is
extremely susceptible to moisture absorption. Always keep
ends of tubing sealed during installation.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
If ANY refrigerant tubing is buried, provide a 6 in. vertical
rise at service valve. Refrigerant tubing lengths up to 36 in.
(914.4 mm) may be buried without further special
consideration, Do not bury lines longer than 36 in. (914,4
mm).
Outdoor units may be connected to indoor section using accessory
tubing package or field-supplied refrigerant grade tubing of correct
size and condition. For tubing requirements beyond 80 ft. (24.38
m), substantial capacity and performance losses can occur.
Following the recommendations in the Application Guideline and
Service Manual-Residential Split-System Air Conditioners and
Heat Pumps Using Puron® Refrigerant will reduce these losses.
Refer to Table 1 for field tubing diameters. Refer to Table 2 for
accessory requirements.
Outdoor Unit Connected to Factory-Approved Indoor
Unit
Outdoor unit contains correct system refrigerant charge for
operation with factory-approved, ARI-rated indoor unit with
highest sales volume when connected by 15 ft. (4.57 m) of
field-supplied or factory-accessory tubing, and factory-supplied
filter drier. Check refrigerant charge for maximum efficiency.

Table1-Refrigerant Connections and Recommended Liquid and Vapor Tube Diameters (in.)
Information is Specific to 25HNA6 and 25HNA9 Models
UNIT SIZE
25HNA624
25HNA636
25HNA648
25HNA660
RATED VAPOR*
Tube
Diameter
5/8
3/4
7/8
1-1/8
Connection
Diameter
3/8
3/8
3/8
3/8
LIQUID
Tube
Diameter
3/8
3/8
3/8
3/8
Connection
Diameter
5/8
3/4
7/8
7/8
3/4
3/4
7/8
1-1/8
Tube diameters are for total equivalent lengths (T.E.L.) up to 80 ft. (24.38 m) Consult the Long Line Guideline--Air Conditioners and Heat Pumps using
Puron¢_ refrigerant.
Do not apply capillary tube or the fixed orifice indoor coils to these units.
For Tubing Set lengths between 80 and 200 ft. (24.38 and 60.96 m) horizontal or 20 ft. (6.10 m) vertical differential (250 ff./76.2 m Total Equivalent Length),
refer to the Longline Guideline- Air Conditioners and Heat Pumps using Puron ® Refrigerant.
25HNA924 3/8 3/8 3/4
25HNA936 3/8 3/8 3/4
25HNA948 3/8 3/8 7/8
25HNA960 3/8 3/8 7/8
Units are rated with 25 ft. (7.6 m) of lineset. See Product Data sheet for performance data when using different size and length linesets.
Notes:
1.
2.
3
Table 2 -Accessory Usage
REQUIRED FOR REQUIRED FOR LONG LINE REQUIRED FOR SEA
LOW-AMBIENT COOLING
ACCESSORY APPLICATIONS* COAST APPLICATIONS
APPLICATIONS (Over 80 ft/24.38 m) (Within 2 miles/3.22 km)
(Below 55°F/12.8 °C)
Crankcase Heater Standard Standard Standard
Standard with Infinity" Control
Evaporator Freeze Protection (Low Ambient not allowed with non- No No
communicating thermostat)
Standard with Infinity Control
Winter Start Control (Low Ambient not allowed with non- No No
communicating thermostat)
Standard on 25HNA6 models. Standard on 25HNA6 models. Standard on 25HNA6
models.
Compressor Start Assist Capacitor Not required on 25HNA9 models Not required on 25HNA9 models Not required on 25HNA9
and Relay:[: since compressor always starts since compressor always starts models since compressor
unloaded, unloaded, always starts unloaded.
Standard with Infinity Control (Low
Low-Ambient Control ambient not allowed with non-commu- No No
nicating thermostat)
Support Feet Recommended No Recommended
Liquid- Line Solenoid Valve No Yes No
Puron Refrigerant Balance Port Yest Yest Yest
Hard- ShutOff TXV
For tubing set lengths between 80 and 200 ft. (24.38 and 60.96 m) horizontal or 20 ft. (6.10 m) vertical differential (total equivalent length), refer to the Long
Line Guideline--Air Conditioners and Heat Pumps using Purcn® Refl'igerant.
1- Required on all indoor units. Standard on all new Purcn refrigerant fan coils and furnace coils.
$ Information is specific to 25HNA6 and 25HNA9 models.
Pu ron
the environmenta ly sould r eldge_ant
Idealt_rniditf_
A_{stane_rd21012_0
Un_r_ _e_t Pumps
ISO 9001:2000 A
C US
__kThinks. Heats. Saves.
Ready for use in a Hybrid Heat ®Duel Fuel system.
meet Energy Star@ criteria for energy efficiency when
matched with appropriate coil components. However,
proper refrigerant charge and proper air flow are critical
to achieve rated capacity and efficiency. Installation of
this product should follow all manufacturing refrigerant
charging and air flow instructions. Failure to confirm
proper charge and air flow may reduce energy
efficiency and shorten equipment life.

Install Liquid-Line Filter Drier Indoor
Refer to Fig. 3 and install filter drier as follows:
1. Braze 5-in. (127 ram) liquid tube to the indoor coil.
2. Wrap filter drier with damp cloth.
3. Braze filter drier to above 5-in. (127 ram) liquid tube. Flow
arrow must point towards indoor coil.
4. Connect and braze liquid refrigerant tube to the filter drier.
I
UNIT DAMAGE HAZARD I
I
Failure to follow this caution may result in equipment damage
or improper operation,
Installation of filter drier in liquid line is required,
and indoor coil are now ready for leak testing. This check should
include all field and factory joints,
Evacuate Refrigerant Tubing and Indoor Coil
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation,
Never use the system compressor as a vacuum pump.
Refrigerant tubes and indoor coil should be evacuated using the
recommended deep vacuum method of 500 nficrons. The alternate
triple evacuation method may be used. See Service Manual for
triple evacuation method. Always break a vacuum with dry
nitrogen.
Deep Vacuum Method
The deep vacuum method requires a vacuum pump capable of
pulling a vacuum of 500 nficrons and a vacuum gauge capable of
accurately measuring this vacuum depth. The deep vacuum method
is the most positive way of assuring a system is free of air and
liquid water. (See Fig. 4)
A05227
Fig. 3 -Liquid-Line Filter Drier
Refrigerant Tubing connection Outdoor
Connect vapor tube to fitting on outdoor unit vapor service valves
(see Table 1).
Install Adapter Tube
1. Remove plastic retainer holding outdoor piston in liquid
service valve.
2. Check outdoor piston size with matching number listed on
unit rating plate.
3. Locate plastic bag taped to unit containing adapter tube.
4. Remove Teflon® washer from bag and install on open
end of liquid service valve.
5. Remove adapter tube from bag and connect threaded nut to
liquid service valve. Tighten nut finger tight and then with
wrench tighten an additional 1/2 turn (15 ft-lb).
DO NOT OVERTIGHTEN!
Sweat Connections
[]NIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation,
• Use a brazing shield
• Wrap service valves with wet cloth or heat sink material.
Use refrigerant grade tubing. Service valves are closed from factory
and ready for brazing. After wrapping service valve with a wet
cloth, braze sweat connections using industry accepted methods
and materials. Consult local code requirements. Refrigerant tubing
ffJ
O
tr"
O
m
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
1 2 3 45 6
MINUTES
Fig. 4 - Deep Vacuum Graph
A95424
Final Tubing Check
IMPORTANT: Check to be certain factory tubing on both indoor
and outdoor unit has not shifted during shipment. Ensure tubes are
not rubbing against each other or any sheet metal. Pay close
attention to feeder tubes, making sure wire ties on feeder tubes are
secure and tight.
Make Electrical Connections
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
iniury or death.
Do not supply power to unit with compressor ternfinal box
cover removed.
Be sure field wiring complies with local and national fire, safety,
and electrical codes, and voltage to system is within linfits shown
on unit rating plate. Contact local power company for correction of
improper voltage. See unit rating plate for recommended circuit
protection device.

NOTE:Operationofunitonimproperlinevoltageconstitutes
abuseandcouldaffectunitreliability.Seeunitratingplate.Donot
installunitinsystemwherevoltagemayfluctuateaboveorbelow
permissiblelimits.
NOTE:Usecopperwireonlybetweendisconnectswitchandunit.
NOTE:InstallbranchcircuitdisconnectofadequatesizeperNEC
tohandleunitstartingcurrent.Locatedisconnectwithinsightfrom
andreadilyaccessiblefromunit,perSection440-14ofNEC.
Route Ground and Power Wires
Remove access panel to gain access to unit wiring. Extend wires
from disconnect through power wiring hole provided and into unit
control box.
ELECTRICALSHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
The unit cabinet must have an uninterrupted or unbroken
ground to minimize personal injury if an electrical fault
should occur. The ground may consist of electrical wire or
metal conduit when installed in accordance with existing
electrical codes.
Connect Ground and Power Wires
Connect ground wire to ground connection in control box for
safety. Connect power wiring to contactor as shown in Fig. 5.
DISCONNECT
PER N. E. C. AND/OR
LOCAL CODES
FIELD POWER ]
WIRING
CONTACTOR
FIELD GROUND
WIRING ] GROUND
LUG
Fig. 5 - Line Power Connections
Connect Control Wiring
A91056
Route low voltage control wires through control wiring grommet
and connect leads to control board.
For 25HNA9 models, connect to Infinity connections ABCD only.
Standard non-communicating thermostats are not allowed unless it
is an emergency that User Interface is not working properly and
new User Interface is not available. For emergency use, connect to
standard thermostat connections R, C, W, YI, Y2, and O.
NOTE: When unit is operating in emergency mode, STATUS
light will flash rapidly. Unit will operate in high stage ONLY.
For 25HNA6 models, connect to ABCD for Infinity Control or
standard thermostat connections R, C, WI, YI, Y2, and O.
General Information
Use No. 18 AWG color-coded, insulated (3. C minimum) wire for
all installations.
All wiring must be NEC Class 1 and must be separated from
incoming power leads.
Use furnace transformer, fan coil transformer, or accessory
transformer for control power, 24v/40va minimum. The outdoor
unit requires a minimum of 27va/24vac control power.
Final Wiring Check
IMPORTANT: Check factory wiring and field wire connections
to ensure terminations are secured properly. Check wire routing to
ensure wires are not in contact with tubing, sheet metal, etc.
Compressor Crankcase Heater
Furnish power to crankcase heater a minimum of 24 hr before
starting unit. To furnish power to heater only, set thermostat to
OFF and close electrical disconnect to outdoor unit.
NOTE: On 25HNA6 models, starting the compressor without a
minimum of 12 hours of crankcase heat prior to initial start-up
may result in a compressor chattering noise and possible damage to
the compressor.
Install Accessories
Refer to the individual instructions packaged with kits or
accessories when installing.
Make Airflow Selections
Airflow Selection for Variable Speed Furnaces for
25HNA6 models only Using Non-Communicating
(non-Infinity) Thermostats
The variable speed furnaces provide blower operation to match the
capacities of the compressor during high and low stage cooling
operation, The furnace control board allows the installing
technician to select the proper airflows for each stage of cooling.
Below is a summary of required adjustments. See furnace
installation instructions for more details:
1. Turn SWl-5 ON for 400 CFM/ton airflow or OFF for 350
CFM/ton airflow. Factory default is OFF.
2. The A/C DIP switch setting determines airflow during high
stage cooling operation. Select the A/C DIP switch setting
corresponding to the available airflow shown in the furnace
installation instructions that most closely matches the re-
quired airflow shown in the air conditioning Product Data
for HIGH speed.
3. The CF DIP switch setting determines airflow during low
stage cooling operation. Select the CF DIP switch setting
corresponding to the available airflow shown in the furnace
installation instructions that most closely matches the re-
quired airflow shown in the air conditioning Product Data
for LOW speed.
If a higher or lower Continuous Fan speed is desired, the
Continuous Fan speed can be changed using the fan switch on the
thermostat. Refer to the furnace installation instructions for details
of how to use this feature.
Airflow Selection for FV4 Fan Coils for 25HNA6
Series Only Using Non-Communicating (Non-Infinity)
Thermostats
The FV4 provides high- and low-stage blower operation to match
the capacities of compressor at high- and low-stage. To select
recommended airflow, refer to FV4 Installation Instructions. The
FV4 utilizes an Easy Select control board thatallows the installing
technician to select proper airflows. For adjustments to control
board, select appropriate HP SIZE and CFM ADJUST setting. This
fan coil has an adjustable blower off delay factory set at 90 sec for
high- and low-stage blower operation.
When using a communicating (Infinity) control, dipswitch
adjustments are not necessary. Airflows are determined by Infinity
Control setup. The fan coil is the FE4A or FE5A.

ForothercombinationsofequipmentconsultProductDataDigest.
Start-Up
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this caution may result in minor personal
injury, equipment damage or improper operation.
Observe the following:
1. Do not overcharge system with refrigerant.
2. Do not operate unit in a vacuum or at negative pressure.
3. Do not disable low pressure switch
4. Dome temperatures may be hot.
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal injury.
Wear safety glasses, protective clothing, and gloves when
handling refrigerant.
ENVIRONMENTAL HAZARD
Failure to follow this caution may result in environmental
damage.
Federal regulations require that you do not vent
refrigerant to the atmosphere. Recover during system
repair or final unit disposal.
Follow these steps to properly start up the system:
1. After system is evacuated, fully back seat (open) liquid and
vapor service valves.
2. Unit is shipped with valve stem(s) front seated (closed) and
caps installed. Replace stem caps after system is opened to
refrigerant flow (back seated). Replace caps finger-tight and
tighten with wrench an additional 1/12 turn.
3. Close electrical disconnects to energize system.
4. Set room thermostat or User Interface at desired temperat-
ure. Be sure set point is below indoor ambient temperature
and is set low enough to energize desired stage.
5. Set room thermostat or User Interface to COOL and fan
control to ON or AUTO mode, as desired. Operate unit for
15 minutes. Check system refrigerant charge.
NOTE: For 25HNA6 Series only using non-communicating
(non-Infinity) thermostat. Carrier electronic thermostats are
equipped with a 15-minute staging timer. This timer prevents the
two-stage system from operating at high stage until unit has been
operating in low stage for 15 minutes, unless there is at least a ---5°F
(-2.8°C) difference between room temperature and thermostat set
point. To force high stage (after a minimum of 2 minutes in low
stage), adjust the set point at least -5°F (-2.8°C) below room
ambient.
6. Set room thermostat or User Interface to HEAT or COOL
and fan control to AUTO or ON, as desired. Wait for appro-
priate time delay(s). Operate unit for 15 minutes. Check re-
frigerant charge.
System Functions and Sequence of Operation
The outdoor unit control system has special functions, The
following is an overview of the two-stage control flmctions:
Cooling and Heating Operation
The 25HNA6 model utilizes either astandard indoor thermostat or
Infinity Communication User Interface. The 25HNA9 models
utilize an Infinity communicating User Interface only. With a call
for first stage cooling, the outdoor fan, reversing valve, and low
stage compressor are energized. If low-stage cannot satisfy cooling
demand, high-stage cooling is energized by the second stage of
indoor thermostat or User Interface. After second stage is satisfied,
the unit returns to low-stage operation until first stage is satisfied
or until second stage is required again. When both first stage and
second stage cooling are satisfied, the compressor will shut off. The
reversing valve will remain energized until the control board power
is removed or a call for heating in initiated. With a call for heating,
the outdoor fan and compressor are energized. The compressor will
operate in high or low stage operation, as needed to meet the
heating demand. When the heating demand is satisfied, the
compressor and fan will shut off. The reversing valve is
de-energized in the heating mode.
NOTE: When two-stage unit is operating at low-stage, system
vapor (suction) pressure will be higher than a standard single-stage
system or high-stage operation.
NOTE: Outdoor fan motor will continue to operate for one
minute after compressor shuts off, when outdoor ambient is greater
than or equal to 100°F. This reduces pressure differential for easier
starting on next cycle.
NOTE: On 25HNA6 models, if unit has not operated within the
past 12 hours, or following a unit power-up, upon the next
thermostat high- or low-stage demand, unit operates for a
minimum of 5minutes in high-stage.
On 25HNA6 models with non-communicating (non-Infinity)
systems, with first stage of cooling, Y1 and O are powered on; and
with second stage of cooling, Y1, Y2, and O are on. For these
systems, with first stage of heating Y1 is on and for second stage of
heating, Y1 and Y2 are on. When the reversing valve is energized,
O is powered on.
Communication and Status Function Lights
For Infinity Control only, Green communications (COMM)
Light
Agreen LED (COMM light) on the outdoor board (see Fig. 6)
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.

Amber Status Light
An amber colored STATUS light is used to display the operation
mode and fault codes as specified in the troubleshooting section.
See Table 6 for codes and definitions.
NOTE: Only one code will be displayed on the outdoor unit
control board (the most recent, with the highest priority).
Utility Interface
With Infinity Control
The utility curtailment relay should be wired between R and Y2
connections on the control board for Infinity Communicating
Systems only (see Fig. 6.) This input allows a power utility device
to interrupt compressor operation during peak load periods. When
the utility sends a signal to shut the system down, the User
Interface will display, "Curtailment Active".
One Minute Stage Change Time Delay on 25HNA6
Models
When compressor changes stages from high to low or low to high,
there is a l-minute time delay before compressor restarts. The
outdoor fan motor remains running.
Compressor Operation on 25HNA6 Models
When the compressor operates in high stage operation, the
compressor motor rotates clockwise. Both the lower and upper
pistons are eccentric with the rotating crankshaft and both
compress refrigerant.
When the compressor operates in low stage operation, the
compressor motor reverses direction (rotates counterclockwise).
The lower piston becomes idle and the upper piston compresses
refrigerant. The start and run windings are reversed.
Crankcase Heater Operation
The crankcase heater is energized during unit off cycle regardless
of outside air temperature (OAT) on 25HNA6 models.
The crankcase heater is energized during off cycle below 65°F
(18.33°C) on 25HNA9 models.
Outdoor Fan Motor Operation
The outdoor unit control energizes outdoor fan anytime
compressor is operating, except for defrost or low-ambient
cooling. The outdoor fan remains energized if a pressure switch or
compressor overload should open. Outdoor fan motor will
continue to operate for one minute after the compressor shuts off
when the outdoor ambient is greater than or equal to 100°F
(37.78°C). This reduces pressure differential for easier starting on
next cycle. On 25HNA6 models, the outdoor fan remains
energized during the l-minute compressor staging time delay.
On 25HNA6 models, the outdoor fan motor is a PSC type. A fan
relay on the control board turns the fan off and on by opening and
closing a high voltage circuit to the motor. It does not change
speeds between low and high stage operation.
On 25HNA9 models, the outdoor fan is an ECM type. The motor
control is continuously powered with high voltage. The motor
speed is determined by electrical pulses provided by the PWM
outputs on the control board. The ECM motor RPM adjusts to
outdoor conditions as described in Table 3. The PWM output can
be measured with a volt meter set to DC volts.
In low ambient cooling (below 55°F/12.78°C) on 25HNA6 and
25HNA9 models, the control board cycles the fan off and on.
Table 3 -Outdoor Fan Motor PWM Above 55°F(12.78°C)
Outdoor Temp (DC volts, Tolerance +/- 2%)
Model
25HNA924
25HNA966
25HNA948
25HNA960
Low Staae
(OAT_t 04 °F /
40°C)
8.72
9.06
9.91
10.83
Hiah Staae
(OAT_104 ° F /
40°()
9.35
10.26
11.04
11.7
Low & Hiah
Sta_ag__
(OAT> t 04 ° F /
40°C)
11.9
11.9
11.9
11.9
NOTE: For 25HNA9 models in low-ambient cooling, the PWMoutput for
both high- and low-stage equals the value for low-stage opera-
tion below 104°F (40°C).
Time Delays
The unit time delays include:
• Five minute time delay to start cooling or heating operation
when there is a call from the thermostat or user interface. To
bypass this feature, momentarily short and release Forced
Defrost pins.
• Five minute compressor re-cycle delay on return from a
brown-out condition.
• Two minute time delay to return to standby operation from last
valid conmmnication (with Infinity only).
• One minute time delay of outdoor fan at termination of cooling
mode when outdoor ambient is greater than or equal to 100°F
(37.78°C).
• Fifteen second delay at termination of defrost before the
auxiliary heat (Wl) is de-energized.
• Twenty second delay at termination of defrost before the outdoor
fan is energized.
• Thirty second compressor delay when quiet shift enabled.
• On 25HNA6 models there is a 1 minute time delay between
staging from low to high and from high to low capacity. On
25HNA9 models there is no delay; the compressor will change
from low to high and from high to low capacity "on the fly" to
meet the demand.
Compressor Operation on 25HNA9 Models:
The basic scroll design has been modified with the addition of an
internal unloading mechanism that opens a by-pass port in the first
compression pocket, effectively reducing the displacement of the
scroll. The opening and closing of the by-pass port is controlled
by an internal electrically operated solenoid. The modulated scroll
uses a single step of unloading to go from full capacity to
approximately 67% capacity.
A single speed, high efficiency motor continues to run while the
scroll modulates between the two capacity steps. Modulation is
achieved by venting a portion of the gas in the first suction pocket
back to the low side of the compressor, thereby reducing the
effective displacement of the compressor.
Full capacity is achieved by blocking these vents, thus increasing
the displacement to 100%. A DC solenoid in the compressor
controlled by a rectified 24 volt AC signal in the external solenoid
plug moves the slider ring that covers and uncovers these vents.
The vent covers are arranged in such a manner that the compressor
operates at approximately 67% capacity when the solenoid is not
energized and 100% capacity when the solenoid is energized. The
loading and unloading of the two step scroll is done "on the fly"
without shutting off the motor between steps.
NOTE: 67% compressor capacity translates to approximately
75% cooling or heating capacity at the indoor coil.
The compressor will always start unloaded and stay unloaded for
five seconds even when the thermostat is calling for high stage
capacity.

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A06525
Fig. 6 -2-Stage Control Board
GENERAL INFORMATION
Low Ambient Cooling
When this unit is operating below 55°F (12.78°C) outdoor
temperature, provisions must be made for low ambient operation.
Infinity Controlled low ambient cooling:
This unit is capable of low ambient cooling without a kit ONLY
when using Infinity control. A low ambient kit is not required, and
the outdoor fan motor does not need to be replaced for Infinity
controlled low ambient operation. The Infinity Control provides an
automatic evaporator coil freeze protection algorithm that
eliminates the need for an evaporator freeze thermostat. Low
ambient cooling must be enabled in the User Interface set up. Fan
may not begin to cycle until about 40°F (4.4°C) OAT. Fan will
cycle based on coil and outdoor air temperature.
Infinity controlled low ambient mode operates as follows:
• Fan is OFF when outdoor coil temp is < (outdoor air temperature
+ 3 oF/1.7 oC) or outdoor fan has been ON for 30 nfinutes. (Fan is
turned off to allow refrigerant system to stabilize.)
• Fan is ON when outdoor coil temp > (outdoor air temperature +
25 oF/13.9 oC) or outdoor coil temp > 80 °F/26.7 oC or if outdoor
fan has been OFF for 30 minutes. (Fan is turned on to allow
refrigerant system to stabilize.)
• Low pressure switch is ignored for first 3 nfinutes during low
ambient start up. After 3 minutes, if LPS trips, then outdoor fan
motor is turned off for 10 minutes, with the compressor running.
If LPS closes within 10 nfinutes then cooling continues with the
outdoor fan cycling per the coil temperature routine listed above
for the remainder of the cooling cycle. If the LPS does not close
within 10 nfinutes, then the normal LPS trip response (shut down
cooling operation and generate LPS trip error) will occur.
For 25HNA9 models, the PWM output for both high and low stage
equals the value for low stage operation below 104°F (40°C).
Defrost
This control offers 5possible defrost interval times: 30, 60, 90, 120
nfinutes, or AUTO.
On 25HNA6 models, these are selected by dip switches on the unit
control board or by the Infinity Control User Interface. The
A06526
Infinity Control selection overrides the control board dip switch
settings.
On 25HNA9 ,the defrost interval times: 30, 60, 90, and 120
nfinutes or AUTO are selected by the Infinity Control User
Interface (the dip switches are not used.)
AUTO defrost adjusts the defrost interval time based on the last
defrost time as follows:
• When defrost time <3 nfinutes, the next defrost interval=120
minutes.
• When defrost time 3-5 nfinutes, the next defrost interval=90
minutes.
• When defrost time 5-7 nfinutes, the next defrost interval=60
minutes.
• When defrost time >7 nfinutes, the next defrost interval=30
nfinutes.
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 nfinutes
during the interval.
The defrost cycle is ternfinated when the coil temperature reaches
65°F (18.33°C)or 10 nfinutes has passed.
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
nfinutes. Remaining intervals are at selected times.
• Defrost is only allowed to occur below 50°F (10°C)outdoor
ambient temperature.
Defrost Hold
On 25HNA6 models, in a non-conmmnicating system, if the
thermostat becomes satisfied (YI or YI and Y2) before the defrost
cycle is ternfinated, the control will "hold" in defrost mode and
finish the defrost cycle on the next call for heat.
On 25HNA6 models, with conmmnicating Infinity Control and all
25HNA9 models, defrost hold is not needed in a conmmnicating
system because the User Interface will complete the defrost cycle
before shutting down the system.

Forced Defrost
On 25HNA6 models with non-conmmnicating (non-Infinity)
control, forced defrost can be initiated by manually shorting the
2-pin header labeled FORCED DEFROST (see Fig 6) on the
control board for 5 seconds then releasing.
On 25HNA6 and 25HNA9 with communicating (Infinity) control,
forced defrost is initiated with the User Interface.
On all models, during a Forced Defrost:
• If coil temperature is at defrost temperature of 32°F (0°C), and
outdoor air temperature is below 50°F (10°C), a full defrost
sequence will occur.
• If coil temperature or outdoor air temperature does not meet the
above requirements, an abbreviated 30 second defrost will occur.
Quiet Shift
Quiet Shift is a field-selectable defrost mode which may eliminate
occasional noise that could be heard at the start of the defrost cycle
and restarting of the heating cycle. On 25HNA6 models with
non-conmmnicating system, this feature nmst be enabled by
selecting the 3rd position of the 3-position dip switch. For
25HNA6 and 25HNA9 models with communicating (Infinity)
systems, it must be enabled at the User Interface. When activated,
the following sequence of operation will occur. Reversing valve
will energize and compressor will turn off for 30 seconds, then turn
back on to complete defrost. At the end of the defrost cycle, the
reversing valve de-energizes, compressor will turn off for another
30 seconds, and the fan will turn off for 40 seconds, before starting
in the heating mode.
Liquid-Line Solenoid Accessory
In heat pump long-line applications, a liquid-line solenoid is
required to control refrigerant migration in the heating mode. The
solenoid should be installed near the outdoor unit with the arrow
facing the outdoor unit. This is the direction of flow control. See
application manual for long-line application details.
Accessory Liquid Solenoid with Infinity Communicating
Control: When using the Infinity Control, the liquid-line solenoid
output is provided at the YI connection. Connect the solenoid as
shown in the wiring label diagram. This is a 24vac output that is
energized whenever the compressor is energized. It closes, in the
compressor off mode, to prevent refrigerant migration into the unit
through the liquid-line.
On 25HNA6 Models with Accessory Liquid Solenoid Using a
Non-Communicating Thermostat: The liquid solenoid is
connect to the YI and C terminal connections. The liquid solenoid
closes, in the compressor off mode, to prevent refrigerant migration
into the unit through the liquid-line.
Check Charge
All 25HNA6 units must be charged in high stage only.
Factory charge amount and desired subcooling are shown on unit
rating plate. Charging method is shown on information plate inside
unit. To properly check or adjust charge, conditions must be
favorable for subcooling charging. Favorable conditions exist
when the outdoor temperature is between 70°F and 100°F
(21.11°C and 37.78°C), and the indoor temperature is between
70°F and 80°F (21.11°C and 26.67°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 of 3/8 liquid line above or below
15ft (4.57 m) respectively.
For standard refrigerant line lengths (80 ft/24.38 m or less), allow
system to operate in cooling mode at least 15 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 15 minutes to stabilize before declaring a properly
charged system.
If the indoor temperature is above 80°F (26.67°C), and the
outdoor temperature is in the favorable range, adjust system charge
by weight based on line length and allow the indoor temperature to
drop to 80°F (26.67°C) before attempting to check system charge
by subcooling method as described above.
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) only. Charge level should then
be appropriate for the system to achieve rated capacity. The charge
level could then be checked at another time when the both indoor
and outdoor temperatures are in a more favorable range.
NOTE: If line length is beyond 80 ft (24.38 m) or greater than 20
ft (6.10 m) vertical separation, See Long Line Guideline for
special charging requirements.
Heating Check Chart Procedure
To check system operation during heating cycle, refer to the Heat
Pump Charging Instructions label on outdoor unit. This chart
indicates 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: In heating mode, check refrigerant charge only when
pressures are stable. If in doubt, remove charge and weigh in
correct refrigerant charge.
NOTE: When charging is necessary during heating season, charge
must be weighed in accordance with unit rating plate, ---0.6 oz./ft.
of 3/8-in. liquid-line above or below 15 ft., respectively.
EXAMPLE:
To calculate additional charge required for a 25-ft. line set:
25 ft. - 15 ft. = 10 ft. X 0.6 oz./ft. = 6 oz. of additional charge.
MAJOR COMPONENTS
2-Stage Control Board
The HP control board controls the following flmctions:
• High and low stage compressor contactor operation
• Outdoor fan motor operation
• Reversing valve operation
• Defrost operation
•Low ambient cooling
• Crankcase heater operation
• Compressor external protection
• Pressure switch monitoring
• Time Delays
• On 25HNA6 models, high- and low-stage start relay and
capacitor operation (Bristol compressor only)
Field Connections
On 25HNA6 models with non-conmmnicating (non-Infinity)
system, the two-stage control receives 24vac low-voltage control
system inputs through the R, C, Y1, Y2 and O connections located
at the bottom of the control board (see Fig. 6.) On a
non-communicating system, output Wl is connected at the bottom
of the control board for auxiliary heat.
On 25HNA6 models with conmmnicating system and all 25HNA9
models, use the ABCD Infinity connections.
Two Stage Compressor
The two stage compressor contains motor windings that provide
2-pole (3500 RPM) operation. For two-stage compressor, refer to
Table 5 for correct winding resistance.
Compressor Internal Relief
The compressor is protected by an internal pressure relief (IPR)
which relieves discharge gas into the compressor shell when
differential between suction and discharge pressure exceeds
10

500-550psion25HNA6modelsand550-625psion25HNA9
models.Thecompressorisalsoprotectedbyaninternaloverload
attachedtomotorwindings.
Compressor Control Contactors
The contactor(s) have a 24volt coil. The electronic control board
controls the operation of the appropriate contactor.
TROUBLESHOOTING
Systems Communication Failure
If conmmnication with the Infinity control is lost with the User
Interface, the control will flash the @propriate fault code. (See
Table 6.) Check the wiring to the UI and the indoor and outdoor
units.
Model Plu_
Each control board contains a model plug. The correct model plug
must be installed for or the system to operate properly. (See Table
4.)
Table 4- Model Plug Information
MODEL
NUMBER
MODEL
PLUG
NUMBER
PIN RESISTANCE
(K-ohms)
Pins 1-4
5.1
5.1
5.1
5.1
25HNA624 HK70 EZO02
25HNA636 HK70 EZO04
25HNA648 HK70 EZO06
25HNA660 HK70 EZO08
25H NA924 HK7OEZ010 5.1 120
25H NA936 HK7OEZ012 5.1 180
25H NA948 HK7OEZ014 5.1 270
25H NA960 HK7OEZ016 11 5.1
Pins 2-3
18
33
51
75
The model plug is used to identify the type and size of unit to the
control. On 25HNA6 models, the model plug is also used to
determine the start sequence timing for each individual model.
On new units, the model and serial numbers are input into the
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 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.
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.
Pressure Switch Protection
The outdoor unit is equipped with high- and low-pressure
switches. If the control senses the opening of ahigh- or
low-pressure switch, it will respond as follows:
1. De-energize the appropriate compressor contactor.
2. Keep the outdoor fan operating for 15 minutes.
3. Display the appropriate fault code (see Table 6).
4. After a 15 minute delay, if there is a call for cooling or heat-
ing and LPS or HPS is reset, the appropriate compressor
contactor is energized.
5. If LPS or HPS has not closed after a 15 minute delay, the
outdoor fan is turned off. If the open switch closes anytime
after the 15 minute delay, then resume operation with a call
for cooling or heating.
6. If LPS or HPS trips 3 consecutive cycles, the unit operation
is locked out for 4 hours.
7. 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 in-
door airflow in heating.
8. In the event of a low-pressure switch trip or low-pressure
lockout, check the refrigerant charge and indoor airflow
(cooling) and outdoor fan operation and outdoor coil in
heating.
Control Fault
If the outdoor unit control board has failed, the control will flash
the appropriate fault code (see Table 6). The control board should
be replaced.
Brown- Out Protection
If the line voltage is less than 187v for at least 4 seconds, the
appropriate compressor contactor and fan relay are de-energized.
Compressor and fan operation are not allowed until voltage is a
n_ininmm of 190v. The control will flash the appropriate fault code
(see Table 6).
230V Line (Power Disconnect) Detection
If there is no 230v at the compressor contactor(s) when the indoor
unit is powered and cooling or heating demand exists, the
appropriate fault code is displayed. Verify the disconnect is closed
and 230v wiring is connected to the unit.
Compressor Voltage Sensing
The control board input terminals labeled VS, VR and L2 on
25HNA6 models and VS and L2 on 25HNA9 models (see Fig. 6)
are used to detect compressor voltage status and alert the user of
potential problems. The control continuously monitors the high
voltage on the run capacitor of the compressor motor. Voltage
should be present any time the compressor contactor is energized
and voltage should not be present when the contactor is
de-energized.
Contactor Shorted Detection
If there is compressor voltage sensed when there is no demand for
compressor operation, the contactor may be stuck closed or there
may be a wiring error. The control will flash the appropriate fault
code.
25HNA6 Models - Compressor Thermal Cutout
The control senses the compressor voltage at VR and VS. When
starting or running, a phase difference of the voltages on the inputs
will indicate the thermal protector is closed. If the phase difference
is 5 ° or less for 10 seconds, the internal protector is open. The
control de-energizes the appropriate compressor contactor for 15
minutes, but continues to operate the outdoor fan. The control
Status LED will flash the appropriate code shown in Table 6. After
15 minutes, with a call for low or high stage cooling or heating, the
appropriate compressor contactor is energized. If the thermal
protector has not re-set, the outdoor fan is turned off. If the call for
cooling or heating continues, the control will energize the
compressor contactor every 15 minutes. If the thermal protector
closes, (at the next 15 minute interval check) the unit will resume
operation.
If the thermal cutout trips for three consecutive cycles, then unit
operation is locked out for 4 hours and the appropriate fault code is
displayed.
25HNA9 Compressor Thermal Cutout
If the control senses the compressor voltage after start-up and is
then absent for 10 consecutive seconds while cooling or heating
demand exists, the thermal protector is open. The control
de-energizes the compressor contactor for 15 minutes, but
continues to operate the outdoor fan. The control Status LED will
flash the appropriate code shown in Table 6. After 15 minutes,
with a call for low or high stage cooling or heating, the compressor
contactor is energized. If the thermal protector has not re-set, the
outdoor fan is turned off. If the call for cooling or heating
11

continues, the control will energize the compressor contactor every
15 minutes. If the thermal protector closes, (at the next 15 minute
interval check) the unit will resume operation.
If the thermal cutout trips for three consecutive cycles, then unit
operation is locked out for 4 hours and the appropriate fault code is
displayed.
Low or High Contactor Open (25HNA6 models) /No
230V at Compressor Contactor (25HNA9 models)
If the compressor voltage is not sensed when the compressor
should be starting, the appropriate contactor may be stuck open or
there is a wiring error. The control will flash the appropriate fault
code. Check the contactor and control box wiring.
25HNA6 Models Only -Compressor Start Detection
on Models with Bristol Compressors Only
In low stage, if the specified start voltage at VR terminal is not
achieved, the start relay is de-energized after 1 second and the
control will flash the appropriate fault code.
In high stage, if the specified start voltage at VS terminal is not
achieved, the start relay is de-energized after 1 second and the
control will flash the appropriate fault code.
If the specified start voltage is not achieved for 3 consecutive low
stage starts, low stage operation is locked out for 30 minutes. If the
specified start voltage is not achieved for 3 consecutive high stage
starts, high stage operation is locked out for 30 minutes. The
control will flash the appropriate fault code.
Troubleshooting 25HNA6 units for proper switching
between low & high sta_es
Check the suction and liquid pressures at the service valves.
Suction pressure should be reduced by 5-10% when switching
from low to high capacity. There should be a10-20% increase in
liquid pressure when switching from low to high capacity.
Compressor current should increase 100-250% when switching
from low to high stage.
Troubleshooting 25HNA9 units for proper switching
between low & high sta_es
Check the suction pressures atthe service valves. Suction pressure
should be reduced by 3-10% when switching from low to high
capacity.
NOTE: The liquid pressures are very similar between low and
high stage operation, so liquid pressure should not be used for
troubleshooting.
Compressor current should increase 20-45% when switching from
low to high stage. The compressor solenoid when energized in
high stage, should measure 24vac.
When the compressor is operating in low stage the 24v DC
compressor solenoid coil is de-energized. When the compressor is
operating in high stage, the 24v DC solenoid coil is energized. The
solenoid plug harness that is connected to the compressor HAS an
internal rectifier that converts the 24v DC signal to 24v AC. DO
NOT INSTALL APLUG WITHOUT AN INTERNAL
RECTIFIER.
Unloader Test Procedure
The unloader is the compressor internal mechanism, controlled by
the DC solenoid, that modulates between high and low stage. If it
is suspected that the unloader is not working, the following
methods may be used to verify operation.
1. Operate the system and measure compressor amperage.
Cycle the unloader on and off at 30 second plus intervals at
the UI (from low to high stage and back to low stage). Wait
5seconds after staging to high before taking a reading. The
compressor amperage should go up or down at least 20 per-
cent.
2. If the expected result is not achieved, remove the solenoid
plug from the compressor and with the unit running and the
UI calling for high stage, test the voltage output atthe plug
with a DC voltmeter. The reading should be 24 volts DC.
3. If the correct DC voltage is at the control circuit molded
plug, measure the compressor unloader coil resistance. The
resistance should be 32 to 60 ohms depending on com-
pressor temperature. If the coil resistance is infinity, nmch
lower than 32 ohms, or is grounded, the compressor nmst
be replaced.
Temperature Thermistors
Thermistors areelectronic devices which sense temperature. As the
temperature increases, the resistance decreases. Thermistors are
used to sense outdoor air (OAT) and coil temperature (OCT).
Refer to Fig. 7for resistance values versus temperature.
THERMISTOR CURVE
9o1 _ r ] r q
| _ I I I I I |
701 t , t , 1
6o4 'v4 LI _ I 4
U 5°1 t I t I 1
z 404 _\ •I•I J
_< / ",. Iiii/
co 301 m _ I t I 1
/ i /
10 t _ t _ 1
0 20 40 60 80 100 120
(-17.77) (-6.67) (4.44) (15.56) (26.67) (37.78) (48.89)
TEMPERATURE °F (°C)
A08054
Fig. 7-Resistance Values Versus Temperature
If the outdoor air or coil thermistor should fail, the control will
flash the appropriate fault code. (See Table 60
IMPORTANT: The outdoor air thermistor and coil thermistor
should be factory mounted in the final locations. Check to ensure
thermistors are mounted properly per Fig. 8 and Fig. 9.
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 -> 10°F
(->5.6 o C) warmer than the coil sensor (or) the outdoor air sensor
indicates ->20 °F (-> 11 oC) cooler than the coil sensor, the
sensors are out of range.
• In heating if the outdoor air sensor indicates ->35 °F (-> 19.4 ° C)
warmer than the coil sensor (or) the outdoor air sensor indicates
->10°F (-> 5.6°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 6.
The thermistor comparison is not performed during low ambient
cooling or defrost operation,
12

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, low ambient cooling will not be
allowed and the one-minute outdoor fan off delay will not occur.
Defrost will be initiated based on coil temperature and time.
If the OCT sensor should fail, low ambient cooling will not be
allowed. Defrost will occur at each time interval during heating
operation, but will terminate after 5 minutes.
OAT Thermistor must be locked in
place with spherical nib end facing to-
wards the front of the control box
\\
If there is a thermistor out of range error, defrost will occur at each
time interval during heating operation, but will terminate after 5
minutes.
Count the number of short and long flashes to determine the
appropriate flash code. Table 6 gives possible causes and actions
related to each error.
/
/
/
/
/
/
/
/
/
/
....
OCT Thermistor
must be secured
tight on stub tube.
Fig. 9 - Outdoor Coil Thermistor (OCT) Attachment
Table 5-Two-Stage Compressor Resistances
(Winding Resistance at 70 °F_+20 °F/21 ° C_+ 11 °C)
25HNA624 25HNA636 25HNA648
2.74 1.98 1.55
0.80 0.75 0.48
Winding 25HNA660
Start (S-C) 0.74
Run (R-C) 0.36
Winding 25HNA924 25HNA936 25HNA948 25HNA960
Start (S-C) 1.40 1.29 1.52 0.60
Run (R-C) 1.32 0.89 0.64 0.49
13

Status Codes
Table 6 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 aseries 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.
EXAMPLE:
3 short flashes followed by 2 long flashes indicates a 32 code.
Table 6 shows this to be low pressure switch open.
Table 6 - TROUBLESHOOTING
AMBER LED
OPERATION FAULT FLASH POSSIBLE CAUSE AND ACTION
CODE
On solid, no
Standby - no call for unit operation None flash Normal operation
Standard Thermo- Rapid, con- Unit being controlled by standard thermostat inputs instead of Infinity Con-
Emergency Mode - Model 25HNA9 stat Control tinuous flash- trol. Only high stage operation is available. This operating mode should be
only (25HNA9 only) ing used in emergency situations only.
Low Stage Cool/Heat Operation None 1, pause Normal operation
High Stage Cool/Heat Operation None 2, pause Normal operation
System Commu- 16 Communication with User Interface lost. Check wiring to UI, indoor and
nications Failure outdoor units
Control does not detect a model plug or detects an invalid model plug. Unit
Invalid Model Plug 25 will not operate without correct model plug.
High Pressure 31 * High-pressure switch trip. Check refrigerant charge, outdoor fan operation
Switch Open and coils for airflow restrictions.
Low Pressure 32* Low-pressure switch trip. Check refrigerant charge and indoor air flow.
Switch Open
Control Fault 45 Outdoor unit control board has failed. Control board needs to be replaced.
Line voltage < 187v for at least 4 seconds. Compressor and fan operation
Brown Out (230 v) 46 not allowed until voltage>__190v. Verify line voltage.
There is no 230v at the contactor when indoor unit is powered and cooling/
No 230v at Unit 47 heating demand exists. Verify the disconnect is closed and 230v wiring is
connected to the unit.
Outdoor Air Temp 53 Outdoor air sensor not reading or out of range. Ohm out sensor and check
Sensor Fault wiring.
Outdoor Coil Sen- 55 Coil sensor not reading or out of range. Ohm out sensor and check wiring.
sor Fault
Thermistors out of 56 Improper relationship between coil sensor and outdoor air sensor. Ohm out
range sensors and check wiring.
Low Stage Ther- Compressor operation detected then disappears while low stage demand
mal Cutout 71 * exists. Possible causes are internal compressor overload trip or start relay
and capacitor held in circuit too long (if installed).
High Stage Ther- Compressor operation detected then disappears while high stage demand
mal Cutout 72* exists. Possible causes are internal compressor overload trip or start relay
and capacitor held in circuit too long (if installed).
Contactor Shorted 73 Compressor voltage sensed when no demand for compressor operation
exists. Contactor may be stuck closed or there is a wiring error.
No 230V at Com-
pressor (25HNA9 74 Compressor voltage not sensed when compressor should be starting. Con-
Only) tactor may be stuck open or there is a wiring error.
Low Stage Did Not Specified start voltage at VR terminal was not achieved in low stage. Start
Start 75
(25HNA6 Only) relay was de-energized after 1 second.
Low Stage Did Not For 3 consecutive low stage starts, the specified start voltage at VR terminal
Start 3 times 76 was not achieved & start relay was de-energized. Low stage locked out for
(25HNA60nly) 30 minutes.
High Stage Did Not Specified start voltage at VS terminal was not achieved in high stage. Start
Start 77
(25HNA6 Only) relay was de-energized after 1 second.
High Stage Did Not For 3 consecutive high stage starts, the specified start voltage at VS terminal
Start 3 times 78 was not achieved & start relay was de-energized. High stage locked out for
(25HNA6 Only) 30 minutes.
Low Stage Ther- 81 Thermal cutout occurs in three consecutive low/high stage cycles. Low
mal Lockout stage locked out for 4 hours or until 24v power recycled.
High Stage Ther- 82 Thermal cutout occurs in three consecutive high/low stage cycles. High
mal Lockout stage locked out for 4 hours or until 24v power recycled.
Low-Pressure 83 Low pressure switch trip has occurred during 3 consecutive cycles. Unit
Lockout operation locked out for 4 hours or until 24v power recycled.
High-Pressure 84 High pressure switch trip has occurred during 3 consecutive cycles. Unit
Lockout operation locked out for 4 hours or until 24v power recycled.
Low Contactor
Open 85 Compressor voltage not sensed when compressor should be starting. Low
(25HNA6 Only) stage contactor may be stuck open or there is a wiring error.
High Contactor Compressor voltage not sensed when compressor should be starting. High
Open 87
(25HNA6 Only) stage contactor may be stuck open or there is a wiring error.
Sequence: Compressor contactor is de-energized and outdoor fan is energized for up to 15 minutes. If demand still exists, control will energize compressor contactor after 15
minute delay. If fault is cleared, unit will resume operation. If fault still exists, fan shuts off, and error code continues to flash. Control will attempt re-start every 15 minutes.
Cycling low voltage defeats the 15 minute delay.
14

THERMtDISTAT
RVS/Heat Stage 2
Heat Stage 1
Compressor Low
Compressor High
Fan
24VAC Hot Heating
24VAC Hot Cooling
Dry Contact 1
Dry Contact 2
24VAC Common
Humidify
Outdoor Air Temp
Remote Room Sensor
OAT/RRS Corn
FAN 2 STAGE
COIL HEAT PUMP
--" _ HEAT STAGING
: EMOME
I
I r--" "_ MODEsDEHUMIDIFY
-J I
, ©..
I
I
_ \
Humidifier Solenoid x
-] I Valve*
-]_ Outdoor Sensor * _i
Remote Room "i
I ,£_n _nr * I
I I
£ ................................ i
A08055
Fig. 10 -Edge Thermidistat Models TP-PRH-01 or TP-NRH-01)
Wiring with 25HNA6 Two-Stage Heat Pump (non-communicating)
(applies to 25HNA6 Models Only)
THERMIDISTAT (TSTAT)
RVS COOLING
HEAT/COOL STAGE 1
(COMPRESSOR LO)
HEAT STAGE 3
(FURNACE)
HEAT/COOL STAGE 2
(COMPRESSOR HI)
FAN _
24 VAC HOT
24 VAC COMM I_
N/A I_
RVS SENSING [_
O ET sOCR__[E2
CONNEDT'ON
VARIABLE SPEED
FURNACE
_[_
HUM
OUTDOOR _
SENSOR
TWO-STAGE
HEAT PUMP
A08090
Fig. 11 - Thermidistat Model TSTATCCPRH01-B with Variable
Speed Furnace and 25HNA6 Two-Stage Heat Pump (non-communi-
cating) (applies to 25HNA6 Models Only)
User Interface
Humidifier
Furnace or Fan Coil
m
rr
>-
o
mm O
m
!
Communicating HP
A08091
Fig. 12 -Infinity Furnace or Fan Coil Wiring with 25HNA6 OR 25HNA9 Communicating Two-Stage HP
15

FINALCHECKS
IMPORTANT:Beforeleavingjob,besuretodothefollowing:
1.Ensurethatallwiringisroutedawayfromtubingandsheet
metaledgestopreventrub-throughorwirepinching.
2.Ensurethatallwiringandtubingissecureinunitbefore
addingpanelsandcovers.Securelyfastenallpanelsand
covers.
3.Tightenservicevalvestemcapsto1/12-turnpastfinger
tight.
4.LeaveUsersManualwithowner.Explainsystemoperation
andperiodicmaintenancerequirementsoutlinedinmanual.
5.FilloutDealerInstallationChecklistandplacein
customerfile.
CAREANDMAINTENANCE
Forcontinuinghighperformanceandto minimizepossible
equipmentfailure,periodicmaintenancemustbeperformedonthis
equipment.
Frequencyofmaintenancemayvarydependingupongeographic
areas,suchascoastalapplications.SeeOwner'sManualfor
information.
PURON® (R-410A) REFRIGERANT QUICK REFERENCE GUIDE
6. Puron refrigerant operates at 50-70 percent higher pressures than R-22. Be sure that servicing equipment and replacement
components are designed to operate with Puron refrigerant.
7. Puron refrigerant cylinders are rose colored.
8. Recovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.
9. Puron refrigerant systems should be charged with liquid refrigerant. Use a commercial type metering device in the manifold hose
when charging into suction line with compressor operating.
10. Manifold sets should be 700 psig high side and 180 psig low side with 550 psig low-side retard.
11. Use hoses with 700 psig service pressure rating.
12. Leak detectors should be designed to detect HFC refrigerant.
13. Puron refrigerant, as with other HFCs, is only compatible with POE oils.
14. Vacuum pumps will not remove moisture from oil.
15. Do not use liquid-line filter driers with rated working pressures less than 600 psig.
16. Do not leave Puron refrigerant suction line filter driers in line longer than 72 hours.
17. Do not install a suction-line filter drier in liquid-line.
18. POE oils absorb moisture rapidly. Do not expose oil to atmosphere.
19. POE oils may cause damage to certain plastics and roofing materials.
20. Wrap all filter driers and service valves with wet cloth when brazing.
21. A factory-approved liquid-line filter drier is required on every unit.
22. Do NOT use an R-22 TXV.
23. If indoor unit is equipped with an R-22 TXV or piston metering device, it must be changed to a hard-shutoff Puron refrigerant
TXV.
24. Never open system to atmosphere while it is under a vacuum.
25. When system must be opened for service, recover refrigerant, evacuate then break vacuum with dry nitrogen and replace filter
driers. Evacuate to 500 microns prior to recharging.
26. Do not vent Puron refrigerant into the atmosphere.
27. Do not use capillary tube coils.
28. Observe all warnings, cautions, and bold text.
29. All indoor coils must be installed with a hard-shutoff Puron refrigerant TXV metering device.
Copyright 2008 Carrier Corp. *7310 W. Morris St. *Indianapolis, IN 46231 Printed in U.S.A. Edition Date: 07/08
Manufacturer reserves the right to change, at any time, specification8 and design8 without notice and without obligations,
Catalog No: 25HNA-5SI
Replaces: 25HNA-4SI
16