Guardian 4721 Repair Manual page 84

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