DC CONTROL

PART 4

SECTION 4.4

DIAGNOSTIC TESTS

INTRODUCTION

Perform these "Diagnostic Tests" in conjunction with the "Troubleshooting Flow Charts" of Section 4.3.

The test procedures and methods presented in this section are not exhaustive. We could not possibly know of, evaluate and advise the service trade of all conceivable ways in which testing and trouble diagnosis might be performed. We have not undertaken any such broad evaluation.

TEST 41 - CHECK POSITION OF AUTO-OFF-

MANUAL SWITCH

DISCUSSION:

If the standby system is to operate automatically, the generator AUTO-OFF-MANUALswitch must be set to AUTO. That is, the generator will not crank and start on occurrence of a "Utility" power outage unless that switch is at AUTO. In addition, the generator will not exercise every seven (7) days as programmed unless the switch is at AUTO.

PROCEDURE:

With the AUTO-OFF-MANUALswitch set to "AUTO, test automatic operation. Testing of automatic operation can be accomplished by turning OFF the Utility power supply to the transfer switch. When the utility power is turned OFF, the standby generator should crank and start. Following startup, transfer to the standby source should occur. Refer to Section 1.8 in this manual. An "Automatic Operating Sequences Chart" is provided on Page 1.7-2. Use the chart as a guide in evaluating automatic operation.

Following generator startup and transfer to the standby source, turn ON the utility power supply to the transfer switch. Retransfer back to the "Utility" source should occur. After an "engine cool down timer" has timed out, generator shutdown should occur.

RESULTS:

1.If normal automatic operation is obtained, discontinue tests.

2.If engine does NOT crank when "Utility" power is turned off, proceed to Test 42.

3.If engine cranks but won't start, go to Problem 10 in Section 4.3.

4.If engine cranks and starts, but transfer to "Standby" does NOT occur, go to Problem 5 in Section 3.3.

5.If transfer to "Standby" occurs, but retransfer back to "Utility" does NOT occur when utility source voltage is restored, go to Problem 6 in Section 3.3.

TEST 42 - TRY A MANUAL START

DISCUSSION:

The first step in troubleshooting for an "engine won’t crank" condition is to determine if the problem is peculiar to automatic operations only or if the engine won’t crank manually either.

PROCEDURE:

1.On the generator panel, set the AUTO-OFF-MANUAL switch to OFF.

2.Set the generator main line circuit breaker to its OFF or open position.

3.Set the generator AUTO-OFF-MANUAL switch to

MANUAL.

a.The engine should crank cyclically through it s "crank-rest" cycles until it starts.

b.Let the engine stabilize and warm up for a few minutes after it starts.

RESULTS:

1.If the engine cranks manually but does NOT crank automatically, go to Test 43.

2.If the engine does NOT crank manually, proceed to Problem 9 in the "Troubleshooting Flow Charts".

TEST 43- TEST AUTO-OFF-MANUAL SWITCH

DISCUSSION:

When the AUTO-OFF-MANUAL switch is set to AUTO position, battery voltage (12 volts DC) is delivered to the circuit board via Wire 15A, the closed switch terminal, Wire 15A, and Pin 10 of the circuit board connector. This voltage is needed to operate the circuit board.

Setting the switch to its "Manual" position delivers battery voltage to the circuit board for its operation. In addition, when the switch is set to "Manual", 12 volts DC is supplied to the circuit board via Pin 11 of the board, Wire 239, the closed switch contacts, Wire 17 and Pin 9 of the circuit board connector.

Figure 1. Schematic of AUTO-OFF-MANUAL Switch

Page 4.4-1

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Guardian Technologies 4389, 4456, 4390, 4760 Test 41 Check Position of AUTO-OFF Manual Switch, Test 42 TRY a Manual Start