Graco A-25 Test SCR Circuit, Replacing Temperature Control Assembly Modules

Page 27

Test SCR Circuit

1.Test the SCR circuit in the on position:

a.Make sure everything is connected, including the hose.

b. Turn main power ON

.

c.Adjust the hose heat setpoint above the ambi- ent hose temperature.

d.Turn on heat zone by pressing .

e.Hold down to view electrical current. Hose current should ramp up to 45A. If there is no hose current, see E03: No zone current, page 11. If hose current exceeds 45A, see E02: High zone current, page 11. If hose current stays several amps below 45A, hose is too long or voltage is too low.

2.Test the SCR circuit in the off position:

a.Make sure everything is connected, including the hose.

b. Turn main power ON

.

c.Adjust the hose heat setpoint below the ambi- ent hose temperature.

d.Turn on heat zone by pressing .

Using a voltmeter, carefully measure the voltage at the hose connector. You should not get a voltage reading. If you do, the SCR on the temperature control module is bad. Replace the temperature control assembly.

Repair

Replacing Temperature Control Assembly Modules

NOTICE

Before handling assembly, put on static conductive wrist strap to protect against static discharge which can damage assembly. Follow instructions provided with wrist strap.

1. Turn main power off

. Disconnect power

supply.

2.Relieve pressure, page 13.

3.Refer to electrical diagrams. See Reactor A-25 Wir- ing Schematic, page 51. Temperature control assembly is on left side inside cabinet.

4.Remove bolts that secure transformer assembly and slide assembly to side in cabinet.

5.Put on static conductive wrist strap.

6.Disconnect all cables and connectors from assem- bly. See Temperature Control Module, page 26.

7.Remove nuts and take entire temperature control assembly to workbench.

8.Replace defective module.

9.Install assembly in reverse order.

3A1570A

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Image 27

Contents Repair-Parts Important Safety InstructionsContents Manual Description Proportioner ModelsSystems Related ManualsElectric Shock Hazard Fire and Explosion Hazard Equipment Misuse Hazard Important Two-Component Material Information Changing Materials DataTrak Diagnostic Codes Temperature Control Diagnostic CodesSymbol Code Code Name Diagnosis Cause Checks E01 High fluid temperatureCauses of E01 Errors Sensor Connector Continuity Checks Pins Description ReadingE03 No zone current E02 High zone currentE05 Control board over temperature E06 Communication cable unpluggedE99 Loss of communication Before Beginning Repair Pressure Relief ProcedureShutdownOpen Close ParkFlushingPumps and Pressures TroubleshootingProblems PowerProblem Cause Solution Electronics Problem Cause SolutionProblem Cause Solution See E04 Fluid Temperature Sen HeaterSor FTS or thermocouple discon Hose Heat System Problem Cause Solution Follow Pressure Relief Procedure, RepairDisconnect Pump Connect Pump Remove Air Motor Install Air MotorAir Filter Element Removal Air Filter Element InstallationRecirculation / Over Pressure Relief Block Air Inlet Filter / Water Separator Auto DrainBottom of Power Modules Temperature Control ModuleTemperature Control Module Connections Connector DescriptionTest SCR Circuit Replacing Temperature Control Assembly ModulesPrimary Heater Heater ElementLine Voltage KW Dual Zone Heater Thermocouple ThermocoupleHeated Hose Overtemperature SwitchCheck Hose Connectors Pins ResultFluid Temperature Sensor FTS InstallationTest/Removal Transformer Primary Check Transformer Secondary Check Replace TransformerModel Secondary Voltage Size Component Replace Circuit Breaker ModulePump Lubrication System Pump Lubrication SystemTemperature Display Refer to Reactor A-25 Wiring Schematic,Fluid Inlet Strainer Screen Display Module Detail of Membrane Switches and Temperature Display BoardReplace DataTrak Battery or Fuse Replace BatteryReplace Fuse Recommended Spare Parts Accessories7984 100 888 PartsTorque pump locking nuts to 66-74 ft-lbs 90-100 Nm Cart Part Description QtyNipple Screw Control PanelTemperature Control Wheel KitRef. Part Description Qty Fluid Inlet Kit Fluid ManifoldRing Kw Dual Zone Heater, 24J788PLUG, Pipe Air Motor Pump AssemblyAir Tubing Connections Length Connection Outside Ft m FromColor Diameter Breaker Module Phase Reactor A-25 Wiring SchematicPOD Reactor A-25 Wiring Schematic Simplified Schematic, Heater Controls Category Data Technical DataGraco Information Graco Standard Warranty

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