1.18.6. Screed Burner Controls and Indicators Circuit

TM 5-3895-373-20 1.18.6. Screed Burner Controls and Indicators Circuit. The screed burner circuit consists of the screed fuel pump, glow plugs, solenoid valves, screed blowers, indicator lights, and control switches. There are four screed burners, one each for the left and right main and extension screeds. Each screed control panel includes controls for the main and extension screed burners for that side. With the exception of the screed fuel pump switch on the left screed control panel, the two screed control panels are identical. Only the left side will be discussed here. Circuit breaker CB4 supplies power to the screed fuel pump. Placing the screed fuel pump switch on the left screed control panel in the up, ON position, energizes the screed fuel pump and the indicator light. Circuit breaker CB3 supplies 12 VDC to one contact on the main and extension screed burner control switches mounted on the screed control panel. Placing the main screed burner control switch in the up, SPRAY position, routes power to the main screed fuel line isolation valve solenoid and the screed burner indicator light. The extension screed burner control switch performs a similar function for the extension screed burner. Circuit breaker CB2 supplies power to the main screed glow plug through a second contact on the main screed burner control switch. Placing the main screed burner control switch in the down, PREHEAT position, supplies power to the main screed glow plug. The glow plug position is a momentary contact position; the glow plugs will remain energized only as long as the switch is held. The extension screed burner control switch performs the same function for the extension screed burners with the exception that electrical power is supplied by CB1. Circuit breaker CB3 also supplies power to the screed blower switches mounted on the screed control panel. Placing the main screed blower switch in the up, ON position, energizes the screed blower motor and indicator light. The extension screed blower switch performs a similar function for the extension screed blowers. 1-30