Goodman AC 18 Manual

INSTALLATION
& OPERATING
INSTRUCTIONS
CEILINGMOUNTAIRHANDLER
AC SERIES
Made in the USA by:
Goodman Manufacturing Company, L.P.
IO-162C 2550NorthLoopWestSuite400 ACSERIES4/02
Houston,Texas77092
CERTIFIED
FOR CANADA

2
Dimensions
Model A B C D
AC 18 37 1/4 37 11/16 30 6 1/2
AC 24 37 1/4 37 11/16 30 6 1/2
AC 30 43 1/4 40 11/16 36 6 1/2
AC 36 49 1/4 46 11/16 42 6 1/2
ELECT. HEATER
LOCATION
FIGURE1
LAYOUTFOR
AC18,24,30, 36
Grill For Return Air
AndService
Outlet Duct
ToDrain
Plenum
DropCeiling
FIGURE2
DROPCEILING
INSTALLATION

3
SPECIAL INSTRUCTIONS
Thisindoorcoilcontainstheflowratordistributorassembly,whichconsistofaflarenut,distributorbody,coppertubes
feedingthecoil,andtheinternalflowcheckpiston.Referencetheenclosed“PistonSizingChart”formix-matchingof
outdoor/indoorunits.
CHANGE THE PISTON
ThiscoilisfurnishedwithaflowcontrolpistoninstalledthatmatchestheBTUHcapacityofthecoil.Apistonsizethatis
toosmallwillcausestarvingandonethatistoolargewillcauseflooding.Thefollowingchartindicatesthecondensing
unitcapacityandtherecommendedpistonsize.
CONDENSING UNIT
MODEL NOM. COOLING (BTUH) PART NO. PISTON SIZE
AC18 18,000 BT 13690-04 52
AC24 24,000 BT 13690-01 59
AC30 30,000 BT 13690-05 65
AC36 36,000 BT 13690-06 71
1. Usingaback-upwrenchontheflarefitting,removethe
3/8"flarenut.
2. Using the back-up wrench on the distributor body,
removethe3/8"flarefittingandTeflonseal.
3. Usingthewireprovidedwithreplacementpistons,run
wire(hookedend)through hole in piston.
4. Hooknoseendofpistonandliftgentlyfromdistributor
body.
5. Replace piston with one of proper size listed above,
installpistonwithTeflonsealendofpistonindistributor
first.Donotforcepistonintodistributor.
NOTE: With piston in distributor, seal end should be
shown and should not be seen looking in end of
distributor.Piston must be freeto rotate and moveup
anddown.Makesurepistonisfreetomoveindistributor
body.
6. Replace3/8"flarefittingwithTeflonsealusingback-up
wrenchondistributorbody.Torquefittingwith8to10ft.
lb.Donotovertighten.
7. Replace 3/8" flare nut using back-up wrench on flare
fitting. Torque 3/8" flare nut with 40 to 45 ft. lb.
8. Removeoldpistonsizelabelfromoutsideofdistributor
body.Removenewpistonsizelabelfrompolybagnew
pistoncamein and install new sizelabel on outside of
distributor.
9. Checkfittingforleaksafterinstallation,evacuationand
charging of the low side is complete.
INTRODUCTION
WARNING:DONOTCONNECTTOORUSEINCONJUNCTIONWITHTHISUNITANYDEVICESFORTHEPURPOSEOFSAVING
ENERGYORINCREASINGOPERATINGEFFICIENCIES,WHICHHAVENOTBEENTESTEDANDAPPROVEDBYGOODMAN
ORDESIGNCERTIFIEDFORUSEWITHTHISUNIT.SERIOUSDAMAGE,REDUCEDUNITPERFORMANCEANDHAZARDOUS
CONDITIONS MAY RESULT FROM THE USE OF DEVICES WHICH HAVE NOT BEEN APPROVED OR CERTIFIED BY
GOODMAN.
CHECKINGPRODUCTRECEIVED
Uponreceivingtheunit,inspectitforanydamagefromshipment.
Claims for damage, either shipping or concealed, should be
filed immediately with the shipping company. Check the unit
model number, specifications, electrical characteristics,
and accessories to determine if they are correct.
ORDERINGPARTS
When reportingshortages or damages,or ordering repairparts,
give the complete unit model and serial numbers as stamped
on the unit’s nameplate. Order parts through your local
contractor.
Ifacombinationisusedthatrequires
a piston size change, change the
pistoninthedistributorontheindoor
coil before installing the coil and
follow the procedure shown below.
Thisbookletcontainstheinstallationandoperatinginstructions
foryour ceilingmount airhandler. Thereare afew precautions
that should be taken to derive maximum satisfaction from it.
Improper installation can result in unsatisfactory operation or
dangerousconditionsandvoidthewarranty.Readthisbooklet
and any instructions packaged with accessories prior to
installation. Give this booklet to the user and explain its
provisions. The user should retain this booklet for future
reference.

4
I. SPECIFICATIONS
A. GENERAL
These Ceiling mount air handlers are available in
coolingcapacitiesof1.5,2,2.5and3nominaltonsof
cooling.Electricheat models are available incapaci-
ties of 5, 8 and 10 KW.
The units are designed to be installed in a horizontal
positionaboveadroppedceiling.Unitsarenottobe
installedoutsidethestructure.Thesemodelsare
designed for INDOOR USE ONLY.
Theinformationontheratingplateisincompliancewith
the FTC and DOE rating for single phase units in the
U.S.A..
IMPORTANT: The United States Environmental
ProtectionAgency(EPA)hasissuedvariousregu-
lationsregardingtheintroductionanddisposalof
refrigerants in this unit. Failure to follow these
regulations may harm the environment and can
lead to the imposition of substantial fines. Be-
cause these regulations may vary due to the
passageofnewlawswesuggestthatanyworkon
thisunitbedonebyacertifiedtechnician.Should
you have any questions please contact the local
office of the EPA.
B. MAJORCOMPONENTS
The unit includes a evaporator coil with flowrator as-
sembly, an indoor blower and all necessary internal
electricalwiring. The coolingsystem of these units is
factory-evacuated,chargedandperformancetested.
Refrigerant amount and type are indicated on rating
plate.
II. INSTALLATION
A. GENERAL
1a. INSTALLATION — This product is designed and
manufacturedtopermitinstallationinaccordance
with National Codes. It is the installer’s responsi-
bility to install the product in accordance with
NationalCodesand/orprevailinglocalcodesand
regulations.
1b. PRE-INSTALLATIONCHECK-POINTS —Beforeat-
tempting any installation, the following points
shouldbeconsidered:
Structuralstrengthofsupportingmembers
Clearancesandprovisionforservicing
Powersupplyandwiring
Air duct connections
Drain facilities and connections
2b. LOCATION - These units are designed to be in-
stalled in a horizontal position above a dropped
ceiling. The location of the unit should be based
onthoroughconsiderationofthePRE-INSTALLA-
TION CHECK POINTS.
B. INSTALLATION
1. Before locating the unit on the dropped ceiling, make
sure that the strength of the ceiling and beams is
adequate at the point to support the weight involved.
Thisisveryimportantandinstallersresponsibility.The
followinglistshowsapproximate weight of unit.
MODEL WEIGHT (lb.)
AC18 59
AC24 59
AC30 69
AC36 79
2. The unit should be mounded on a horizontal position
above a dropped ceiling of adequate strength (see
Figure2)
3. Thelocationoftheunitshouldprovideproperaccessfor
inspectionandservicing.
C. DUCTING
Duct work should be fabricated by the installing con-
tractorinaccordancewithlocalcodes.Industrymanu-
als maybeusedasaguidewhensizinganddesigning
the duct system - such as NESCA (National Environ-
mental Systems Contractors Association, 1501 Wil-
sonBlvd.,Arlington,Virginia22209).
DO NOT, UNDER ANY CIRCUMSTANCES, CON-
NECTDUCTWORKTOANYOTHERHEATPRODUC-
INGDEVICESUCHASFIREPLACEINSERT,STOVE,
ETC.UNAUTHORIZEDUSEOFSUCHDEVICESMAY
RESULTINFIRE,CARBONMONOXIDEPOISONING,
EXPLOSION, PERSONAL INJURY OR PROPERTY
DAMAGE.
Thisunitshouldbeplacedas close to the space to be
airconditionedaspossible.Adequateclearancemust
bemaintainedasindicatedinSectionF“Clearances”.
Ducts should be run as directly as possible to supply
andreturnoutlets.Useofnon-flammableweatherproof
flexibleconnectorsonbothsupplyandreturnconnec-
tions at unit to reduce noise transmission is recom-
mended.
D. FILTERS
Filtersarenotprovidedwithunit,andmustbesupplied
andinstalledinthereturnairsystembytheinstaller.A
fieldinstalledfiltergrilleisrecommendedforeasyand
convenientaccesstothefilters,forperiodicinspection
andcleaning.Filtersmusthaveadequatefaceareafor
theratedairquantityoftheunit.Theminimumfiltersize
is 20" x 20" x 1".
E. CLEARANCES
These units are U.L. listed for installations with zero
clearancetocombustiblematerials,referenceshould
be made to the marking on the particular unit being
installed where specific information regarding clear-
ancesisprovided.Accessmustbeprovidedforservic-

5
ingthe unit. Iftheseunitsareinstalled in aremovable
ceilingpanel,amplespacemustbeprovidedforservic-
ing the unit.
III. PIPING
CONDENSATEDRAIN
FIGURE3
Thecondensatedrainconnectionoftheevaporatorisahalf
coupling of 3/4" N.P.T. A trap must be provided to have
propercondensatedrainage.SeeFigure3.
Install condensate drain trap as shown. Use 3/4" drain
connection size or larger.Do not operate without trap.
Unit must be level or slightly inclined toward drain.
IV.ELECTRICALWIRING
GENERAL
All wiring should be made in accordance with the
National Electrical Code in the U.S.A. Determine the
availabilityofsufficientpowertooperatetheunit.The
voltageatthepowersupplyshouldbecheckedtomake
sure it corresponds to the unit’s RATED VOLTAGE
REQUIREMENT. Wire sizes should be determined
from the unit nameplate ampacity and in accordance
with Table 1, the National Electrical Code. Under no
circumstances should wiring be sized smaller than is
recommendedbyeitherofthesetwosources.
Theunitmustbepermanentlygroundedinaccordance
withlocalcodes,orintheabsenceoflocalcodes,with
theN.E.C.ANSI/NFPANO.70-1987orlatesteditionin
the U.S.A. To wire units, make the following high and
lowvoltageconnectionsateitherlocation.
1. High Voltage Wiring:
These units are designed for Single phase 208/230 Volt
only, two leads should be connected to terminals L1
andL2onthebreakerintheelectricalcontrolsection,
using wire sizes specified in table 1.
TABLE1 BRANCH CIRCUIT COPPER WIRE SIZE
(Base on 1% Voltage Drop)
200
6 4 4 4 3 3 2 2
SUPPLY WIRE
150
8 6 6 4 4 4 3 3
TW (60C)
100
10 8 8 6 6 6 4 4
LENGTH - FEET 75 12 10 8 8 6 6 4 4
50
14 12 18 10 8 8 6 6
15 20 25 30 35 40 45 50
BRANCH CIRCUIT AMPACITY
NOTE: (Wiring for unit only, no heat kit installed)
a. Wiresizebasedon60°Cratedwireinsulationand30°C
Ambient Temp. (86°F).
b. For branch circuit wiring (main power supply to unit
disconnect),theminimumwiresizeforthelengthofrun
can be determined from Table 2 using the circuit
ampacity found on the unit rating plate. From the unit
disconnect to unit, the smallest wire size allowable in
Table 2 may be used,as the disconnect must be in
sight of the unit.
c. Formorethan3conductorsinaracewayorcable,see
theN.E.C.forderatingtheampacityofeachconductor.
2. LowVoltageWiring: See Figure4forcoolingunit
with electric heat, Figure 5 for heat pump with
electricheat.
Connect24V.wiresfromthethermostattothecorre-
sponding wires in control box using No. 18 AWG as
follows:
LEAD THERMOSTAT NOTES
PINK R (24V) -
GREEN G (FAN) -
-YTO CONDENSING UNIT 24V
CONNECTIONS
WHITE W-
BLUE -TO CONDENSING UNIT 24V
CONNECTIONS
BROWN ETO BE USED FOR
EMERGENCY HEAT ONLY

6
Figure 4
THERMOSTAT
RYGW
BLUE
YELLOW TOCONDENSING UNIT
24 V CONNECTIONS
Figure 5
ElectricalInstallationDiagramForCooling
ElectricalInstallationDiagramForHeatpump
unitwithElectricHeat.
WithElectricHeat.
NOTE:Incaseofheatpumpfailure,switchto
“E” on T’stat for emergency heat.
3. InternalWiring
A diagram of the internal wiring of this unit is located
undertheelectricalboxcover.Ifanyoftheoriginalwire
as supplied with the appliance must be replaced, the
wire gauge and insulation must be same as original
wiring.
4. Transformerisfactorywiredfor230voltson208/230volt
models.Seewiringdiagramfor208voltwiring.For208V
operation,movethewhitetransformerleadfrom240Vto
208Vtap.
THERMOSTAT HEAT
ANTICIPATOR SETTING
AC18, 24, 30, 36 2
MODEL
MAINTENANCE
1) RoomThermostat- Thisisthedevicethatcontrolsthe
operationofyourheatingand/orcoolingunit.Itsenses
the indoor temperature and signals the equipment to
start or stop maintaining the temperature you have
selectedforyourcomfort.Theroomthermostatshould
be in a central, draft free inside wall location for best
operation.Donotplaceanyheatproducingapparatus
suchas lights, radio, etc., near the thermostat as this
willcauseerraticoperationofthecomfortsystem.
2) Air Filter(s) - All central air moving comfort systems
must include air filter(s). These filters will be located
eitherintheequipmentorinthereturnairductsystem
upstreamoftheequipment.Thefilter(s)removesdust
and debris from the air thus helping to keep your
conditioned space clean. More important, the filter
keeps dust and debrisfromcollectingonheattransfer
surfaces thus maintaining optimum equipment effi-
ciencyandperformance.Inspectandcleanorreplace
filterseverymonth.Thisroutinemaintenanceprocedure
will pay big dividends in reduced operating cost and
reducedserviceexpense.Neveroperatecomfortequip-
mentwithoutfilter(s).
3) Fusesand/or Circuit breakers- Thiscomfortequip-
ment should be connected to the building electric
serviceinaccordancewithlocalandNationalElectric
codes. This electrical connection will include over
currentprotectionintheformoffusesorcircuitbreak-
ers.Haveyourcontractoridentifythe circuits and the
locationofovercurrentprotectionsothatyoumaybein
apositionto make inspectionsorreplacementsinthe
eventtheequipmentfailstooperate.Keepreplacement
fusesof the proper sizeon hand.

7
WARNING
a) Do not store combustible materials or use gasoline or other flammable liquids or vapors in the vicinity of
this appliance so as to prevent the risk of property damage or personal injury.
b) Have your contractor point out and identify the various cut-off devices, switches, etc., that serve your
comfortequipment. Thereisaswitchthatwillcut offenergy toyour heatingsystem. Knowwhere theyare
so that you may cut off the flow of energy in the event of overheating.
4) PeriodicCheckupandService- Thisproductisdesignedtoprovidemanyyearsofdependable,trouble-freecomfort
whenproperlymaintained.Propermaintenancewillconsistofannualcheckupsandcleaningoftheinternalelectrical
andheattransfercomponentsbyaqualifiedservicetechnician.Failuretoprovideperiodiccheckupandcleaningcan
resultinexcessiveoperatingcostand/orequipmentmalfunction.
SYMPTOM POSSIBLE CAUSE REMEDY
High head-low suction a. Restriction in liquid line or capillary tube a. Remove or replace defective component
High head-high or normal
suction
a. Dirty condenser coil
b. Overcharged
c.Condenser fan not running
a. Clean coil
b. Correct system charge
c. repair or replace
Low head-high suction
a. Incorrect capillary tube
b. Defective compressor valves
a. Replace evaporator assembly
b. Replace compressor
Unit will not run
a. Power off or loose electrical connection
b. Thermostat cut off calibration set too high
c. Defective contactor
d. Blown fuses or tripped breaker
e. Tansformer defective
f. High or low pressure control open (Optional)
g. Compressor overload contacts open
a. Check for unit voltage at contactor in unit
b. Reset
c. Check for 24 volts at contactor coil replace if
contacts are open
d. Replace fuse or reset breaker
e. Check wiring-replace transformer
f. Reset high pressure control or check unit charge
High pressure control opens at 425psi
Low pressure control opens at 25psi
g. Replace compressor
NOTE: Wait at least 2 hours for overload to reset
Condenser fan runs,
compressor does not
a. Loose connection
b. Compressor stuck, grounded or open
winding/open internal overload
c. Low voltage connection
a. Check for unit voltage at compressor check and
tighten all connections
b. Wait at least 2 hours for overload to reset if still
open, replace the compressor
c. At compressor terminals, voltage must be within
10% of nameplate voltage when unit is operating
Low suction-cool
compressor a. Low indoor airflow a. Increase speed of blower or reduce restriction- replace air filters
Compressor short cycles
a. Defective overload protector
b. Unit cycling on low pressure control
a. Check for correct voltage/replace overload
b. Check refrigerant charge and airflow
Registers sweat a. Low airflow a. Increase speed of blower or reduce restriction-
replace air filters
High suction pressure
a. Excessive load
b. Deffective compressor
a. Recheck load calculation
b. Replace
Insufficient cooling
a. Improperly sized unit
b. Improper airflow
c. Incorrect refrigerant charge
d. Incorrect voltage
a. Recalculate load
b. Check (should be approximately 400 cfm/ton)
c. Charge per unit service panel
d. At compressor terminals, voltage must be within
10% of nameplate voltage when unit is operating
Evaporator coil freezing or
frosting
a. Low airflow
b. Low refrigerant charge
c. Operating unit in cooling mode below 65
degrees F outdoor temperature
a. Check (should be approximately 400 cfm/ton),
dirty air filters, all duct outlets open
b. Properly charge unit
c. Install or check low ambient control, should be
open below 65 degrees F outdoor temperature
TROUBLESHOOTING CHART
WARNING: DISCONNECT ALL POWER TO UNIT BEFORE SERVICING