OM4012.2 Maintenance - Section 4 Automatic Lube System Reciprocating Pump Page 4-17 24 VDC Solid State Timer Check 24 VDC Solid State Timer Adjustment To check the solid state timer operation without waiting for the normal timer setting, proceed as follows: The timer is factory set for a nominal 2.5 minute (off time) interval. Dwell time is approximately 1 minute, 15 seconds. A longer interval (off time) is obtained by turning timer selector (3, Figure 4-4) to the desired position . 1. Remove timer dust cover. NOTE: The timer incorporates a liquid and dust tight cover which must be in place and secured at all times during truck operation . 2. Adjust timer to 5 minute interval setting. 3.
The timer should cycle in five minutes if the truck is operating. NOTE: If the timer check is being made on a cold start, the first cycle will be approximately double the nominal setting. All subsequent cycles should be within the selected time tolerance . 4. Voltage checks at the timer should be accom- plished if the above checks do not identify the problem. a. Insure timer ground connection is clean and tight. FIGURE 4-4. SOLID STATE TIMER ADJUSTMENT b. Using a Volt-Ohm meter, read the voltage be- tween positive and negative posts on the solid state timer with the truck keyswitch "ON". Normal reading should be 18-26 VDC, depend- ing upon whether or not the engine is running. 1. Timer 3.
Timer Selector 2. Red LED (Light Emitting Diode) indicates pump solenoid is "ON". NOTE: Set timer by turning timer selector (3) to the 2.5 minute setting point. Then, turn the selector clockwise, one detent at a time, to the desired setting, or until the maximum limit of eighty minutes is reached . The solid state timer is a sealed unit, do not attempt disassembly.