Guardian Technologies 4270 manual Section ENGINE DC CONTROL SYSTEM, Circuit Condition- Pre-Heat

Section 5

ENGINE DC CONTROL SYSTEM

CIRCUIT CONDITION- PRE-HEAT:

When the PRE-HEAT SWITCH (SW) or the REMOTE PANEL PRE-HEAT SWITCH is closed by the operator, battery voltage is delivered across the closed switch contacts to the PRE-HEAT CONTAC- TOR (PHC) via Wire 150. The PRE-HEAT CONTAC- TOR (PHC) is now energized. The normally open (PHC) contacts close, battery voltage is now avail- able to Wire 157.

The GLOW PLUGS (GP) are energized via Wire 157.

Wire 157 is also connected to a DIODE (D1), current is allowed to pass through (D1) and Wire 14 will now have battery voltage applied to it " Engine Controller Terminals 9, 10 , and 11 are connected".

The FUEL PUMP (FP), FUEL SOLENOID (FS), and HOURMETER (HM) will be energized via Wire 14.

Wire 14 is also connected to RESISTOR (R2) and DIODE (D2). After passing through R2 and D2 reduced voltage is applied to Wire 4.

Page 19