Guardian 4721 Repair Manual page 53

"V-TYPE" PREPACKAGED
TRANSFER SWITCHES
Problem 2 - In Automatic Mode, No Retransfer Back to Utility
TEST 7 - CHECK
VOLTAGE AT
TERMINAL LUGS
N1 & N2
BAD
FIND CAUSE OF NO
UTILITY SOURCE
VOLTAGE TO
TRANSFER SWITCH
REPAIR, RECONNECT
OR REPLACE WIRING
REPAIR OR REPLACE
DEFECTIVE TRANSFER
MECHANISM PART(S)
REPLACE UTILITY
CLOSING COIL C1
REPLACE BAD
LIMIT SWITCH
Problem 3 - In Automatic Mode, Generator Starts and Transfer to Standby Occurs
TEST 10 - CHECK
GOOD
FUSES F1 & F2
BAD
REPLACE
BLOWN
FUSE(S)
TROUBLESHOOT GENERATOR
DC CONTROL SYSTEM
SEE PART 4 AS APPROPRIATE
PART 3
TEST 8 - CHECK
VOLTAGE AT
GOOD
UTILITY 1 AND
UTILITY 2 TERMINALS
REPLACE
BLOWN
BAD
FUSE(S)
BAD
TEST 4 - CHECK
BAD
MANUAL TRANSFER
SWITCH OPERATION
GOOD
TEST 11 - TEST LIMIT
BAD
SWITCH XA1
REPLACE BAD RELAY
When Utility Source Voltage is Available
TEST 7 - CHECK VOLTAGE
AT TERMINAL LUGS N1 & N2
BAD
FIND CAUSE OF NO UTILITY SOURCE
VOLTAGE TO TRANSFER SWITCH
AND CORRECT THE PROBLEM
TROUBLESHOOTING FLOW CHARTS
GOOD
BAD
TEST 10 - CHECK
FUSES F1 & F2
GOOD
TEST 6 - CHECK
WIRING AND WIRING
CONNECTIONS
GOOD
GOOD
VOLTAGE AT UTILITY 1 AND 2
TERMINALS IN TRANSFER
SWITCH IS GOOD
SECTION 3.3
TEST 9 - CHECK
VOLTAGE AT
UTILITY CLOSING
COIL C1
GOOD BUT NO
TRANSFER
BAD
TEST 3 - TEST
TRANSFER
RELAY (TR)
BAD
TEST 8 - CHECK VOLTAGE
AT UTILITY 1 AND
UTILITY 2 TERMINALS
BAD
TEST 6 - CHECK
WIRING AND WIRING
CONNECTIONS
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