Carrier 38YKC Series Manual

®
NOTE TO INSTALLER: THIS MANUAL SHOULD BE LEFT WITH THE EQUIPMENT USER.
This document was created with FrameMaker 4.0.4

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WELCOME TO EFFICIENT
YEAR-ROUND COMFORT
Congratulations on your excellent choice and sound invest-
ment in year-round home comfort!
Yournewheatpumprepresentsboththelatestinengineer-
ingdevelopmentandtheculminationofmanyyearsofexpe-
rience from one of the most reputable manufacturers of
comfort systems.
Your new unit is among the most energy-efficient and reli-
able heat pump products available today. To assure its
dependability, spend just a few minutes with this booklet
now. Learn about the operation of your heat pump, and the
smallamountofmaintenanceittakestokeepitoperatingat
its peak efficiency.
With minimal care, your new heat pump will provide you
andyour family with year-round home comfort—both now
and for years to come.
WARNING
Improper installation, adjustment, alteration, ser-
vice, maintenance or use can cause explosion,
fire, electrical shock, or other conditions which
may cause personal injury or property damage.
Consult a qualified installer, service agency or
your distributor or branch for information or as-
sistance. The qualified installer or agency must
use factory-authorized kits or accessories when
modifying this product.
WARNING
To prevent personal injury, death, or property
damage, read and follow all instructions and warn-
ings, including labels shipped with or attached to
unit before operating your new heat pump.
!
!
YOUR COMFORT SYSTEM
Identifying Your System
Takethetimetofamiliarizeyourselfwiththetypeofsystem
you have. This knowledge will be of use in understanding
the basic operation of your new heat pump.
The split-system type has an indoor and an outdoor unit,
each of which contains a coil. These units are intercon-
nected by refrigerant tubes. (See Fig. 1.)
Eachunithas aratingplateaffixedtoit whichprovides nec-
essary information for specific identification of a unit. You
should familiarize yourself with the product, model, and
serial numbers listed on each rating plate.
IMPORTANT FACTS
Tobetterprotectyourinvestmentandtoeliminateunneces-
sary service calls, familiarize yourself with the following
facts:
• Yourheat pump system should neverbeoperatedwithout
a clean air filter properly installed. Plan to inspect the filter
periodically.Acloggedairfilter will increase operating costs
and shorten the life of the unit.
•Supply-air and return-air registers should not be blocked.
Drapes, furniture,andtoys aresome oftheitemscommonly
found obstructing grilles. Restricted airflow lessens the
unit’s efficiency and life span.
•The outdoor unit must have unrestricted airflow. Do not
cover the unit, lean anything against it, or stand upon it. Do
not allow grass clippings, leaves, or other debris to accumu-
late around or on top of the unit. Maintain a 12-in. minimum
clearance between the outdoor unit and tall grass, vines,
shrubs, etc.
• Yourmultipurpose indoorthermostatisthe control center
for your heat pump system. You should familiarize yourself
with its proper operation. Attempting to control the system
by other means—for instance, switching the electrical sup-
ply power ON and OFF—may cause damage to the unit.
•During heating increasing the thermostat more than 2
degreesmaycausethesupplementalheaterstobeturnedon
tosatisfythethermostat.Needlessuseofthesupplementary
heat reduces potential energy savings.
• You may find that you can maintain greater personal com-
fort by running the fan continuously. “Air pockets” can form
duetothestructureofthehouse,placementofregisters,etc.
These air pockets may be too cool or warm for your liking.
Continuous fan operation minimizes any temperature differ-
ences. Also, systems equipped with electronic air cleaners
and/or humidifiers offertheaddedbenefitsofhavingtheair
continuouslycleanedyear-round,andhumidifiedduringthe
winter season.
• Your heat pump will remove humidity from your home
during the cooling season. After a few minutes of operation,
you should be able to see water trickle from the condensate
drain of the cooling coil. Check this occasionally to be sure
the drain system is not clogged. Of course, don’t expect to
see much drainage if you live in a very dry environment.
•During the heating cycle, air from your registers may
seemcoolerthanyou might firstexpect.Thisisbecause the
airisbeingdeliveredatahighervelocityandamoreconstant
flow than air supplied by a conventional furnace. Also, your
Fig.1—Typical Split-System Installation

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heat pump supplies air at 85 ° to 90 ° F instead of in sudden
bursts of hot air as with a conventional furnace. The air may
feel cool because it is slightly less than your body tempera-
ture. However, it is sufficiently warm to keep you comfort-
able.
•Iceor frostwill tendtoformontheoutdoor coilduringthe
winter heating operation. Your heat pump is designed to
automatically melt the ice. When in this defrost cycle, it is
normalfor steamorfog torisefromthe outdoorunit.Do not
be alarmed!
OPERATING YOUR HEAT PUMP
Theoperationofyourheatpumpsystemiscontrolledbythe
indoor thermostat. You simply adjust the thermostat and it
maintains the indoor temperature at the level you select.
Most thermostats for heat pump systems have 4 controls:
the temperature control selector, FAN switch, SYSTEM
switch, and EMERGENCY HEAT switch.
The temperature control selector is a dial or lever that
allows you to establish the degree of temperature that you
wish to maintain for your personal comfort. Some thermo-
stats possess 2 temperature control selectors: 1 for setting
the temperature desired during the cooling cycle, and 1 to
setthe heating operation temperature. Typicalsettings are
78
° F for cooling and 68 ° F for heating.
The FAN switchoffers2options forcontrolling theblower:
AUTOandON.WhensettoAUTO,theblowerwillrundur-
ing the time the heat pump is operating. When the FAN
switch is set at the ON position, the blower will run contin-
uously.
Typically, the SYSTEM switch on your thermostat offers
thefollowingselections: COOL,OFF,and HEAT. Your ther-
mostat may also have a fourth selection, AUTO. The heat
pumpwillnotoperatewhentheSYSTEMswitchissetatthe
OFFposition.With the SYSTEM switch set at COOL, your
heatpumpwilloperateinitscoolingmodewhentheindoor
temperaturerisesabovethelevelthatyouwishtomaintain.
With the SYSTEM switch set at the HEAT position, your
heat pump will provide warmth whenever the indoor tem-
perature falls below the level that you have selected.
The AUTO selection found on some thermostats provides
for automatic changeover between cooling and heating
cycles. Withthe SYSTEMswitchsetin theAUTOposition,
Energy Saving Heat Pump
50 60 70 80 90
50 60 70 80 90
OFF
HEAT COOL
FAN
AUTO ON
EMERG
HEAT
thecooling modeisactivatedwhentheindoortemperature
rises above the thermostat cooling temperature setting, or
theheatingmodewill be activated whentheindoortemper-
ature drops below the thermostat setting for the heating
cycle.
Dependingonyourtypicalwinterheatingneeds,yourhome
comfort system may include a supplementary heating
source. The EMERGENCY HEAT switch provides for con-
venient selection between the 2 heating appliances. Your
heatpumpwill operatewhenthe switchissetat NORMAL.
With the switch set at the EMERGENCY HEAT position,
the heat pump will turn off and the supplementary heat
source will be activated.
Incertaingeographicareasandincertainapplications,elec-
tric heat is not required. Any questions regarding your
application should be directed to your dealer.
COOLING CYCLE
When operating in the cooling cycle, your heat pump will
rununtil theindoortemperatureisloweredto thelevelyou
haveselected.Onextremelyhotdays,yourconditionerwill
run for longer periods at a time and have shorter “off” peri-
ods than on moderate days.
The following are typical conditions that add extra heat
and/or humidity to your home. Your cooling unit will work
longer to keep your home comfortable under these condi-
tions:
•Entrance doors are frequently opened and closed
•Laundry appliances are being operated
•A shower is running
•More than the usual number of people are present in the
home
•More than the normal number of electric lights are in use
•Drapes are open on the sunny side of the home
HEATING CYCLE
With the SYSTEM switch of your indoor thermostat set to
the HEAT position, the heating section of your home com-
fortsystemwilloperateuntil room temperatureis raised to
the level you have selected. Of course, the heating unit will
havetooperateforlongerperiodstomaintainacomfortable
environment on cooler days and nights than on moderate
ones.
Refer to your furnace User’s Manual for specific informa-
tion on heating operation.
DEFROST CYCLE
When your heat pump is providing heat to your home and
the outdoor temperature drops below 45
° F, moisture may
begintofreezeonthesurfaceoftheoutdoorcoil.Ifallowed
tobuildup,thisicewouldimpedeairflowacrossthecoiland
reduce the amount of heat absorbed from the outside air.
So, to maintain energy-efficient operation, your heat pump
has an automatic defrost cycle.
The defrost cycle starts at a preset time interval of 90 min-
utes, although, it may be reset to either 30 or 50 minutes.
Defrostwillstartatthepresettimeonlyiftheiceissufficient
to interfere with normal heating operation.
After the ice is melted from the outdoor coil, or after a max-
imum of 10 minutes in the defrost mode, the unit will auto-
matically switch back to normal heating operation.
Fig. 2—Manual Changeover Thermostat

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Do not be alarmed if steam or fog appears at the outdoor
unitduringthe defrostcycle.Watervaporfromthemelting
ice may condense into a mist in the cold outside air.
During certain weatherconditionssuchasheavysnowand
freezing rain it is not uncommon for ice to build up on the
outdoor unit grille. This is normal for these weather condi-
tions. Do not attempt to remove the ice from the outdoor
unitgrille.Thisconditionwillnot affectthe proper function
of the unit and will clear within a few days.
EMERGENCY HEAT
The EMERGENCY HEAT setting on your thermostat
refersto any supplementary heating appliance that may be
included in your home comfort system. Operation of the
EMERGENCY HEAT source may be required if heating
demandsexceedthecapacityoftheheatpump,oriftheheat
pump malfunctions.
The red light on your thermostat will illuminate if the
EMERGENCY HEAT switch is moved from NORMAL to
the EMERGENCY HEAT setting. This indicates that the
heat pump is off and the supplemental heating appliance is
selected for operation.
Also,ifyourparticularmodelofheatpumpincludesan“effi-
ciency alarm” circuit, the red light will glow if the compres-
sor malfunctions. Call your dealer for immediate service if
you suspect trouble.
Duringtheheatingseason,switchtoEMERGENCYHEAT
if the electricity to your outdoor unit has been off for more
than 30 minutes for any reason (i.e., power outage). Leave
the switch in the EMERGENCY HEAT position for an
amount of time equal to that during which the power was
off. It isn’t necessary to exceed 12 hours. If you cannot
determine how long the power has been off, leave the
switch in the EMERGENCY HEAT position for 8 hours.
NOTE: The EMERGENCY HEAT switch is effective only
when the SYSTEM switch is set at the HEAT or AUTO
position.
PERFORMING ROUTINE MAINTENANCE
Withthepropermaintenanceandcare,yourheatpumpunit
willoperateeconomicallyanddependably.Maintenancecan
be accomplished easily by referring to the following direc-
tions. However, before performing maintenance, consider
these important safety precautions:
•DISCONNECTALLELECTRICALPOWERTOTHEAIR
CONDITIONER BEFORE REMOVING ACCESS PANELS
TOPERFORMMAINTENANCE.Disconnectpowertoboth
the indoor and outdoor units. NOTE: THERE MAY BE
MORE THAN 1 ELECTRICAL DISCONNECT SWITCH.
• ALTHOUGH SPECIAL CARE HAS BEEN TAKEN TO
MINIMIZESHARPEDGESINTHE CONSTRUCTIONOF
YOUR UNIT, BE EXTREMELY CAREFUL WHEN HAN-
DLING PARTS OR REACHING INTO THE UNIT.
CHECK THE AIR FILTER
A dirty air filter will cause excessive strain on the compres-
sor and blower motor. This can cause the components to
overheat and automatically shut down. In the extreme, the
components will fail and need to be replaced. To avoid inef-
ficient or failed operation of your unit, CHECK THE FIL-
TER(S) EVERY 3 TO 4 WEEKS. Replace filter(s) when
necessary, or clean the filter(s) if you have the reusable
type.
Disposable filtersshouldbe replacedby similar,new filters
of the same dimensions.
Reusable, permanent filtersshouldbe washedinasolution
ofcoldwaterandmilddetergent,thenrinsedandthorough-
ly dried. THE FILTER MUST BE COMPLETELY DRY
BEFORE BEING REINSTALLED. To avoid prolonged
shutdown of your unit while a filter is drying, you should
have an extra filter on hand. This would allow you to rotate
betweenthe2withminimaldowntime foryour comfortsys-
tem. Extra filters may be purchased from your dealer.
There are no filters in the outdoor unit of a split system. If
yourindoorunitisagasoroilfurnace,refertoyourfurnace
User’sManualforfilterlocationandproceduresforreplace-
ment or cleaning.
Ifyoursystemincludesanindoorfancoilunit,thefiltermay
be located in the unit where it connects with the return-air
duct or plenum. (See Fig. 4.) Remove the filter cover plate
by sliding latches toward center of plate. Lift filter to clear
lowerflange.Filterisspring-loadedandwill“popout.”Rein-
stallfilter,beingcertaintosecurefilterbehindlowerflange.
When reinstalling cover plate, secure plate behind upper
flange then slide tabs outward.
Fig. 3—Main Electrical Disconnect
Fig. 4—Removing Filter
from Fan Coil Unit

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The indoor fan coil unit may be located in the attic. In this
instance the filter may be located behind the return air
grille. Access the filter by removing the return air grille.
INDOOR COIL
If the split-system coil has only been operated with a clean
filter in place, it should require minimal cleaning. You may
usea vacuumcleanerandsoftbrushattachmenttoremove
anyaccumulationof dust fromthetopand underside ofthe
finned coil surface. However, perform this maintenance
only when the coil is completely dry.
If you cannot get the coil clean by this method, call your
dealerforservice.Itmaybenecessarytocleanthecoilwith
a detergent solution and rinse it with water. This could
require the removal of the coil. Youshouldnotattemptthis
yourself.
OUTDOOR COIL
If grass clippings, leaves, shrubbery, and debris are kept
away from the outdoor unit, minimal care should be suffi-
cient to keep the system functioning properly. For proper
drainage, debris must be removed periodically from the
basepan. However,ifthe outdoor coil becomes dirty,use a
brushorvacuumcleanerandsoftbrushattachmenttoclean
the exterior surface. If dirt is deep in the coil, contact your
dealer for service. The outdoor fan motor may have to be
disconnected and the top panel removed to gain access to
thecoilforthorough cleaning.Donotattemptthis yourself.
OUTDOOR COIL—SEA COAST
If your unit is located near the ocean, special maintenance
is required. Ocean mist/breeze carries salt, which is corro-
sive to most metals. Although your new unit is made out of
galvanized metal and is protected by top-grade paint, you
shouldtaketheprecautionofadditionalmaintenancewhich
consists of periodically washing the unit. By washing all
exposed surfaces andcoil,youwillbeaddingadditionallife
to your unit. Consult your installing contractor for proper
intervals/procedures for your geographic area or service
contact.
UNIT SUPPORT
Yoursplit-systemoutdoorunitshouldbemaintainedatalev-
elposition.Ifitssupportshouldshiftorsettlesothattheunit
isnolongerlevel,youshouldcorrectthecondition.Relevel
it promptly toassure condensatedrainageoutof theunit.If
you notice that water or ice collects beneath the unit,
arrange for it to be drained away from the unit.
BEFORE YOU REQUEST
A “SERVICE CALL”
BEFORE YOU CALL FOR SERVICE, CHECK FOR
THESE EASILY SOLVED PROBLEMS:
•Checktheindoor andoutdoordisconnectswitches. Verify
that circuit breakers are ON or that fuses have not blown.
•Check for sufficient airflow. Check the air filter(s) for
any accumulations of dirt. Check for blocked return-air
or supply-air grilles. Be sure grilles are open and
unobstructed.
•Check the settings on your indoor thermostat. If you
desire cooling, see that the temperature control selector is
set below room temperature and the SYSTEM switch is on
theCOOLorAUTOposition.Ifyourequire warmth,besure
the temperature control selector is set above room tempera-
tureandtheSYSTEMswitchisatHEATorAUTO.TheFAN
switch should be set at ON for continuous blower operation
orAUTO ifyouwishblowerto functiononlywhiletheunitis
operating.
Ifyourcomfortsystemstillfailstooperate,contactyourser-
vicing dealer for troubleshooting and repairs. Specify your
apparent problem, and state the model and serial numbers
of your equipment. With this information, your dealer may
be able to offer helpful suggestions over the phone or save
valuable time through knowledgeable preparation for the
service call.
REGULAR DEALER MAINTENANCE
In addition to the routine
maintenance that you perform,
your home comfort system
should be inspected regularly
by a properly trained service
technician. The inspection
(preferably twice each year,
but at least once every year)
should include the following:
•Routineinspectionofairfilter(s).Replacementorcleaning
as required.
•Inspectionand cleaningofthe blowerwheel,housing,and
motor as required.
•Inspectionand,ifrequired,cleaningofindoorandoutdoor
coils.
•Inspection of the indoor coil drain pan, plus the primary
andsecondarydrainlines.Ifsupplied,theauxiliarydrainpan
and line should be inspected at this time. Service should
include cleaning if required.
•A check of all electrical wiring and connections.
•Acheckfor securephysicalconnections of individualcom-
ponents within units.
•Operational check of the heat pump system to determine
actual working condition. Necessary repair and/or adjust-
ment should be performed at this time.
Your servicingdealermayofferaneconomicalservice con-
tract that covers seasonal inspections. Ask for further
details.
FOR THE RECORD
Recordthemodel,product,andserialnumbersofyournew
equipment in the spaces provided. This information, along
with the other ready-reference facts requested will be nec-
essary should you ever require information or service.

HEATING & COOLING
TO OBTAIN INFORMATION ON PARTS: Consult your installing dealer or classified section of your local telephone directory under the
“Heating Equipment’’or “Air Conditioning Contractors & Systems’’ headings for dealer listing by brand name.
Have available the Model No., Series Letter & Serial No. of your equipment to insure correct replacement part.
Carrier Corporation Syracuse, New York 13221
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations .
Copyright 1993 Carrier Corporation Form: OM38-31 Replaces: New 0993 Printed in the U.S.A. 6-92 PC 101 Catalog No. 533-868
INSTALLATION DATA
Date Installed
Dealer Name
Address
City
State Zip
Telephone
SPLIT-SYSTEM
OUTDOOR UNIT:
Product No.
Model No.
Serial No.
INDOOR UNIT OR COIL:
Product No.
Model No.
Serial No.
MODULAR INDOOR UNIT, if Applicable:
Blower—Product No.
Model No.
Serial No.
Coil—Product No.
Model No.
Serial No.
Heater—Product No.
Model No.
Serial No.