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TABLE 12-1. TROUBLESHOOTING
WARNING Some genset service procedures present hazards that can result in severe personal
injury or death. Only trained and experienced service personnel with knowledge of fuels,
electricity, and machinery hazards should perform genset service. See Safety Precautions.
VAC SENSE LOST—CODE NO. 27
(The Controller lost VAC sensing during normal voltage regulation when the field was functioning normally
and frequency was at least 40 Hz)
Corrective Action: Refer to Pages A-1, A-2 and A-3, as appropriate.
1. Disconnect harness connector P1 from the control board (p. 11-1) and check for electrical resistance
between pins P1-33 and P1-34, which should be approximately 586 ohms (TX1 secondary winding,
p. 11-5). Go to Step 2 if the secondary circuit of voltage sense transformer TX1 is good. If not, disconnect
the four harness leads from TX1 and test the transformer. Replace the transformer if either winding
is faulty. If the transformer is good, check wiring continuity in harness leads P1-33—TX1-RED
and P1-34—TX1-GRN. Repair or replace components as necessary. Make sure connector pin sockets
are not damaged or corroded and that they are fully seated and can’t be pulled out.
2. Make sure the line circuit breaker (CB1/CB2) is OFF, disconnect the four harness leads from TX1
and test the transformer. Replace the transformer if either winding is faulty. If the transformer is good,
check electrical resistance between harness leads TX1-S1 and TX1-S2, which should be approximately
twice the individual winding resistances in Table 10-1 (T1−T2 + T3−T4). If not, check wiring
continuity in harness leads CB1-LINE—TX1-S1 and CB2-LINE—TX1-S2 and for proper connections
of both sense leads and generator leads to the line terminals on CB1 and CB2. Repair, reconnect
or replace components as necessary.
3. Replace the control board (p. 11-1).
HIGH BATTERY VOLTAGE—CODE NO. 29
(During startup the Controller sensed that battery system voltage was greater than 19.2 volts for 5 milliseconds
or greater than 19.2 volts for 1 second will running)
Corrective Action:
1. Check battery bank connections and reconnect if necessary so that the 12 volt batteries serving the
genset are connected in parallel (12 volt) rather than in series (24 volt).
2. Select a lower battery booster charge rate.
12-9