EngA AF Series

A
AF / DCU MANUAL
IOM-52 10 of 23 Apr 13 R2
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LIQUIDLINESOLENOIDVALVE(Required)
Theliquidlinesolenoidvalveisinstalledtocontrolliquidrefrigerantintheoff
cycle.ThesolenoidvalvemustbeinstalledclosetotheTXvalveattheevaporator
coil.Severaldifferentcontrolmethodsareusedtocontrolliquidlinesolenoid
valves.Seewiringdiagramandunitfunctionfordetails.
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Note:

Liquidlinesolenoidvalvesmustbeinstalledattheevaporatorcoil,closetotheTXvalve.
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THERMOSTATICEXPANSIONVALVE
(Required)
Thethermostaticexpansionvalveissizedtomatchthecapacityofthesystem.The
TXvalveshouldbebalancedordualportedandmustbeexternallyequalized.One
valveisrequiredperdistributor.Theequalizationtubeconnectstothesuctionline
attheoutletoftheevaporatordownstreamofthebulb.TheTXvalvesensingbulb
isinstalledatthesamelocationtightlystrappedtothesuctionline.Suggested
positioningisatthesideofthepipe,atthe4:00o’clockor8:00o’clockposition.InsulatetheTXbulbafter
installation.
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DISCHARGECHECKVALVES(Required)
Providedischargecheckvalve(s)totheinletoftheAF.Thiscontrolsliquidmigrationtothecompressorin
theoffcycle.
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RefrigerationTable1EquivalentLength.
ACR(OD)
Approximatepressurelossoffittings
(equivalentfeetoftubing)
Tubing
Size
90°
Std
90°
Long
Radius
90°
Street
45°
Std
Return
Bend
Tee
Branch
Flow
Tee
Straight
Through
Ball
Valve
Globe
Valve
Angle
Valve
1/2"OD 1.4 0.9 2.3 0.7 2.3 2.7 0.9 0.9 17 6
5/8”OD 1.6 1.0 2.5 0.8 2.5 3.0 1.0 1.0 18 7
7/8”OD 2.0 1.4 3.2 0.9 3.2 4.0 1.4 1.4 22 9
11/8”OD 2.6 1.7 4.1 1.3 4.1 5.0 1.7 1.7 29 12
13/8”OD 3.3 2.3 5.6 1.7 5.6 7.0 2.3 2.3 38 15
15/8”OD 4.0 2.6 6.3 2.1 6.3 8.0 2.6 2.6 43 18
21/8”OD 5.0 3.3 8.2 2.6 8.2 10.0 3.3 3.3 55 24
25/8”OD 6.0 4.1 10.0 3.2 10.0 12.0 4.1 4.1 69 29
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