Guardian 4721, Repair Manual

Page: 84 / 115

TEST 4 - INSPECT AUTO-OFF-
MANUAL SWITCH TO CMA
CIRCUIT BOARD WIRING
TEST 1 - CHECK
POSITION OF
AUTO-OFF-MANUAL
SWITCH
TEST 3 - TEST
AUTO-OFF-MANUAL
SWITCH
TEST 2 - TRY A
MANUAL START
O.K.
SWITCH IS “OFF”
SWITCH IS
IN “AUTO”
DOES NOT
START
MANUALLY
STARTS
MANUALLY
WIRING BAD
WIRING GOOD
RESET SWITCH TO “AUTO”
GO TO PROBLEM 2
REPLACE CMA CIRCUIT BOARD
REPAIR, RECONNECT OR REPLACE BAD WIRING
Problem 1 - Engine Will Not Crank When Utility Power Failure Occurs
BAD
GOOD
TEST 6 - CHECK
BATTERY
TEST 5 - CHECK 30
AMP FUSE
TEST 9 - CHECK
CONTROL BOARD
POWER AND WIRE
56 OUTPUT
TEST 10 - CHECK
FOR MECHANICAL
DAMAGE
TEST 8 - TEST
STARTER
MOTOR
TEST 7 - TEST
CONTROL
CONTACTOR (CC)
TEST 3 - TEST
AUTO-OFF-MANUAL
SWITCH
BAD
POWER SUPPLY TO
BOARD O.K. BUT WIRE 56
OUTPUT IS BAD
POWER SUPPLY TO
BOARD AND WIRE 56
OUTPUT ARE BOTH BAD
ENGINE-
GENERATOR
DAMAGE IS
FOUND
NO ENGINE OR
GENERATOR
DAMAGE IS FOUND
BAD
BAD
GOOD
GOOD
GOOD
GOOD
GOOD
REPLACE BLOWN FUSE
REPLACE CONTROL BOARD
REPLACE CONTROL
BOARD AND TEST
CRANKING
OPERATION
REPAIR /
REPLACE
MOTOR
REPAIR
MECHANICAL
DAMAGE AS
NECESSARY
REPLACE
BAD
REPLACE
DEFECTIVE
SWITCH
RECHARGE / REPLACE
Problem 2 - Engine Will Not Crank When
AUTO-OFF-MANUAL
Switch is Set to “MANUAL”
TEST 4 - INSPECT AUTO-OFF-
MANUAL SWITCH TO
CONTROL BOARD WIRING
WIRING BAD
WIRING GOOD TEST COMPLETE
REPAIR, RECONNECT OR
REPLACE BAD WIRING
PART 4
Page 80
DC CONTROL
LIQUID COOLED
ENGINE UNITS
SECTION 4.3
TROUBLESHOOTING FLOW CHARTS