Troubleshooting CST. Miller BIG BLUE 450 DUO CST, BIG BLUE 450 DUO CST (CST 282)

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Complete Parts List is available at www.MillerWelds.com

H 9

Help 9 Display

Indicates one or both cooling fans are not operating. If this display is shown, contact a Factory Authorized Service Agent.

Help 24, 25 Display

Indicates machine has reached Duty Cycle limit (see Section 4-7).

Unit must be left on to power the fan for cooling. Duty Cycle limit will automatically reset when unit has cooled.

8-13. Troubleshooting CST

Trouble

No Output, unit completely inoperative

Blown fuses.

No weld output

Erratic or improper weld output

Fan not operating

Possible Causes

Faulty output diode(s) D1 or D2 or D3

Faulty HD1

Weld cables too small or defective.

Dirty or loose connections.

Blocked fan.

Fan Failure

8-14. Troubleshooting Generator

Remedy

Check and replace primary fuses F2 thru F7, if necessary.

(See Section 8-11)

Have factory authorized service agent check for shorts or opens in wiring.

Have factory authorized service agent check HD1.

Use proper size and type of weld cable. (See Section 5-8)

Clean and tighten all weld cable connections. (See Sec-

tion 5-9)

Check for and remove anything blocking fan movement.

Have factory authorized service agent check fan motor.

A. Standard Generator Power

Trouble

No generator power output at AC receptacles; weld output okay.

No generator power or weld output.

Remedy

Reset receptacle supplementary protectors (see Section 7-1).

Disconnect equipment from generator power receptacles during start-up.

Reset supplementary protector CB3 (see Section 8-11).

Have Factory Authorized Service Agent check brushes and slip rings, and field excitation circuit.

Have Factory Authorized Service Agent check field excitation circuit.

High output at generator power AC receptacles.

Low output at generator power AC receptacles.

Have engine Factory Authorized Service Agent check engine speed, and adjust if necessary.

OM-294672 Page 49

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Complete Parts List is available at www.MillerWelds.com

B. Engine

Trouble

Engine will not crank.

Engine cranks but does not start.

Engine hard to start in cold weather.

Engine suddenly stops.

Engine slowly stopped and cannot be restarted.

Battery discharges between uses.

Engine uses oil during run-in period; wetstacking occurs.

Remedy

Check battery, and replace if necessary.

Check battery connections and tighten if necessary.

Circuit breaker CB1 may be open. CB1 automatically resets when fault is corrected (see Section 8-

11). Have Factory Authorized Service Agent check engine wiring harness and components.

Reset supplementary protector CB2 (see Section 8-11).

Check engine wiring harness plug connections.

Have Factory Authorized Service Agent check Engine Control switch S1, Fuel/Hour gauge FUEL/

HM, and control relay CR2.

Check fuel level.

Check battery and replace if necessary. Check engine charging system according to engine manual.

Have Factory Authorized Service Agent check control relay CR1, fuel pump, and Fuel/Hour gauge

FUEL/HM.

Air in fuel system. See engine manual.

Use Preheat switch S4 (see Section 6-1).

Keep battery in good condition. Store battery in warm area off cold surface.

Use fuel formulated for cold weather (diesel fuel can gel in cold weather). Contact local fuel supplier for fuel information.

Use correct grade oil for cold weather (see Section 8-1).

Have Factory Authorized Service Agent check Preheat switch S4, control relay CR3, and the glow plug.

Check oil, fuel, and coolant levels. Automatic shutdown system stops engine if oil pressure is too

low, fuel is low, or coolant temperature is too high (see Section 5-5, 5-6, and 5-7).

Check fuel/hour meter for indication of shutdown.

Reset supplementary protector CB2 and/or clear fault causing circuit breaker CB1 to trip (see Sec-

tion 8-11). Have Factory Authorized Service Agent check engine alternator, fuel pump, and engine

harness.

Have Factory Authorized Service Agent check Engine Control switch S1, control relay CR1, integrated rectifier SR2, and the fuel pump.

See engine manual.

Check fuel level.

Check fuel/hour gauge FUEL/HM for indication of shutdown.

Check engine air and fuel filters (see Sections 8-4 and 8-10).

See engine manual.

Turn Engine Control switch off when unit is not running.

Clean top of battery with baking soda and water solution; rinse with clear water.

Recharge or replace battery if necessary.

Periodically recharge battery (approximately every 3 months).

Dry engine according to run-in procedure (see Section 11).

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