Specifications

IM 1049-4 / Page 11 of 36
andblowdown,makingsurecitywaterllvalvesaresetto
makeupwateratthesamerate.Checkthepressuregauge
atpumpsuctionandmanuallyadjustthemakeuptohold
thesamepositivesteadypressurebothbeforeandafter
opening the drain valves. Flush should continue for at least
two hours, or longer if required, to see clear, clean drain
water.
3. Shut off supplemental heater and circulator pump and
open all drains and vents to completely drain down
the system. Short circuited supply and return runouts
shouldnowbeconnectedtotheconditionersupplyand
returnconnections.Donotusesealersattheswivelare
connections of hoses.
4. Trisodium phosphate was formerly recommended as a
cleaningagentduringushing.However,manystatesand
localitiesbantheintroductionofphosphatesintotheir
sewage systems. The current recommendation is to simply
ushlongerwithwarm80°F(27°C)water.
5. Rellthesystemwithcleanwater.Testthewaterusing
litmus paper for acidity, and treat as required to leave
thewaterslightlyalkaline(pH7.5to8.5).Thespecied
percentageofantifreezemayalsobeaddedatthistime.
UsecommercialgradeantifreezedesignedforHVAC
systemsonly.Donotuseautomotivegradeantifreeze.
 Oncethesystemhasbeenlledwithcleanwaterand
antifreeze(ifused),precautionsshouldbetakentoprotect
the system from dirty water conditions. Dirty water will
result in system wide degradation of performance and
solidsmayclogvalves,strainers,owregulators,etc.
Additionally,theheatexchangermaybecomeclogged
which reduces compressor service life or causes premature
failure.
6. Set the loop water controller heat add setpoint to 70°F
(21°C)andtheheatrejectionsetpointto85°F(29°C).
Supply power to all motors and start the circulating
pumps.Afterfullowhasbeenestablishedthroughall
componentsincludingtheheatrejector(regardlessof
season)andairventedandlooptemperaturesstabilized,
eachoftheconditionerswillbereadyforcheck,testand
start-up,airbalancing,andwaterbalancing.
Start-up
1. Open all valves to full open position and turn on power to
the conditioner.
2. Setthermostatfor“FanOnly”operationbyselecting
“Off”atthesystemswitchand“On”atthefanswitch.If
“Auto”fanoperationisselected,thefanwillcyclewith
thecompressor.Checkforproperairdelivery.
3. Forthoseunitsthathavetwo-speedmotors,reconnectfor
low speed operation if necessary.
4. Setthermostatto“Cool.”Ifthethermostatisanautomatic
changeover type, simply set the cooling temperature to the
coolest position. On manual changeover types additionally
select“Cool”atthesystemswitch.
Again, many conditioners have time delays which protect
the compressor(s) against short cycling. After a few
minutesofoperation,checkthedischargegrillesforcool
airdelivery.Measurethetemperaturedifferencebetween
enteringandleavingwater.Itshouldbeapproximately
1½ times greater than the heating mode temperature
difference. For example, if the cooling temperature
difference is 15°F (8°C), the heating temperature
differenceshouldhavebeen10°F(5°C).
 Withoutautomaticowcontrolvalves,targetacooling
temperature difference of 10°F to 14°F (5°C to 8°C).
Adjustthecombinationshutoff/balancingvalveinthe
returnlinetoawaterowratewhichwillresultinthe
10˚Fto14°F(5°Cto8°C)difference.
5. Setthermostatto“Heat.”Ifthethermostatistheautomatic
changeovertype,setsystemswitchtothe“Auto”position
and depress the heat setting to the warmest selection.
Someconditionershavebuilt-intimedelayswhich
prevent the compressor from immediately starting. With
most control schemes, the fan will start immediately. After
afewminutesofcompressoroperation,checkforwarm
airdeliveryatdischargegrille.Ifthisisa“coldbuilding”
start-up,leaveunitrunninguntilreturnairtotheunitisat
least 65°F (18°C).
 Measurethetemperaturedifferencebetweenenteringand
leaving air and entering and leaving water. With entering
water of 60°F to 80°F (16°C to 27°C), leaving water
shouldbe6°Fto12°F(3.3°Cto6.6°C)cooler,andtheair
temperature rise through the machine should not exceed
35°F (19°C). If the air temperature exceeds 35°F (19°C),
thenthewaterowrateisinadequate.
6. Checktheelevationandcleanlinessofthecondensateline.
Iftheairistoodryforsufcientdehumidication,slowly
pour enough water into the condensate pan to ensure
proper drainage.
7. Iftheconditionerdoesnotoperate,checkthefollowing
points:
 a. Issupplyvoltagetothemachinecompatible?
 b. Isthermostattypeappropriate?
 c. Isthermostatwiringcorrect?
8. Iftheconditioneroperatesbutstopsafterabriefperiod:
 a. Isthereproperairow?Checkfordirtylter,incorrect
fanrotation(3-phasefanmotorsonly),orincorrect
ductwork.
 b. Isthereproperwaterowratewithintemperature
limits?Checkwaterbalancing;backushunitifdirt-
clogged.
9. Checkforvibratingrefrigerantpiping,fanwheels,etc.
10.Donotlubricatethefanmotorduringtherstyearof
operationasitisprelubricatedatthefactory.
11. Field supplied relays installed on the input terminals W1,
W2, Y1, Y2 or G may introduce electrical noise. Never
install relay coils in series with the inputs.