Proheat X45–School Bus - Manual (Page 110)

© 1995 Marine Canada Acquisition Inc. DBA SEASTAR SOLUTIONS 3831 No. 6 Road, Richmond, B.C. Canada V6V 1P6 Tel: 604.270.6899 Web: www.proheat.com
SER VICE BULLETIN
Copy Part# SB0003, Rev. A, 06/1995 Page 1 of 2
Description: Ground Side Battery Disconnect
Purpose:
This service bulletin includes troubleshooting steps and protection
recommendations from damage, that may occur when attempting an
engine start while the ground side battery disconnect switch is in the
"open" position. A Proheat is typically connected directly to the batteries
so that it can be used to preheat the coolant when the ground side battery
disconnect switch is "open". If the operator (driver) attempts to start the
engine with this switch "open" the entire electrical current from the starter
motor attempts to pass through the proheat internal wiring harness.
Without adequate fuse protection the Proheat ground circuit in the internal
harness and/or controller will be damaged.
Test Procedure:
The symptoms may include a START error or FLAME OUT error. The fuel
pump will not operate if the Proheat ground circuit has been damaged,
resulting in intermittent operation of the Proheat.
1. Start the Proheat. Check that the fuel pump is running. Approximately
20 to 40 pulses per minute can be felt or heard. Check for voltage at
the fuel pump power terminal.
2. If the fuel pump does not operate, ground the body of the fuel pump
directly to the battery negative post using a wire. Restart the Proheat.
If the fuel pump runs and the Proheat starts then the problem is in the
ground wire.
Note: It is possible to get a partial ground for the fuel pump if the
exhaust pipe is contacting the machine frame and the ground
side battery disconnect switch is closed.
3. To locate the fault in the ground circuit, first check the internal
harness. The ground wire is black with a green stripe. Remove the 18
pin connector from the controller and check for continuity between the
ground pin (Pin C3) and the ring terminal. See Figure 1 (over). If a fault
is found replace the harness. Next, check the controller by measuring
for continuity between pin C3 on the controller 18 pin connector and
pin B at the power harness connector. See Figure 2.
4. If the fuel pump did not run in step 2 refer to Fuel Pump, Start error and
Flame Out error in the troubleshooting section of the Service Manual.
Recommended
Method of Protection:
1. Install a 10 amp in-line fuse on the ground wire (black with green stripe)
of the Proheat harness. Proheat Part# PK0310.
2. Ensure that the Proheat exhaust pipe does not contact vehicle chassis.
3. If possible rewire the disconnect switch to the positive side of the battery.