Problem	Probable Cause	Remedy
Burner on drum mixer or aggregate dryer fires sporadically or shuts off	1. Clogged fuel line.	1. Clean preheater heating coil assembly and inside of shell
	2. Water or steam in fuel line.	2. Drain water from preheater
Fuel pump cavitates	1. Strainer at suction side of fuel pump is clogged.	1. Clean strainer. Replace strainer basket if necessary.
	2. Valve at suction side of fuel pump is closed.	2. Open valve.
Fuel temperature does not rise when preheater is turned on.	1. Relay inside preheater control panel is bad.	1. Test the relay. If it is bad, replace it.
	2. Auxiliary contacts on fuel pump motor starter arebad or are not installed properly.	2. Make sure auxiliary contacts are installed properly. if they are installed properly and the problem persisits, replace the contacts.
	3. Valve at thermal fluid inlet is closed.	3. Open valve.
	4. Auxiliary pump at hot oil heater is turned off.	4. Turn on auxiliary pump.
	5. Hot oil heater is turned off.	5. Start hot oil heater.
	6. Fuel preheater is clogged.	6. Clean fuel preheater.
	7. Controller set point too low.	7. Adjust set point.
	8. Controller is defective.	8. Replace controller.
	9. Actuator coupling is damaged or defective.	9. Repair or replace coupling.
	10. Thermal fluid temperature too low.	10. Adjust set point on thermal fluid heater.
Fuel temperature does not reach set point.	1. Heating coil assembly is fouled.	1. Clean preheater heating coil assembly and inside of shell.
	2. Thermal fluid flow rate is too low.	2. Check thermal fluid circulation pump.
	3. Thermal fluid temperature is too low.	3. Make sure thermal fluid heater is operating properly. Raise set point on heater.
	4. Too much water in fuel.	4. Drain water from preheater.
	5. PID settings in controller are wrong.	5. Check to see if the PID settings are different than those noted during initial startup. if the settings are different, re-set them or Auto-Tune controller.
	6. Weather has turned much colder since initial startup.	6. Auto-Tune controller per instructions in Setting Yokogawa Controller Tec-Note.
Fuel overheats.	1. Thermal fluid inlet valve is stuck open.	1a. Lubricate thermal fluid inlet valve.
		1b. Actuator may be bad. Re-Tune controller. If thermal fluid inlet valve does not open and close, replace actuator.
	2. PID settings in controller are wrong.	2. Check to see if the PID settings are different than those noted during initial startup. If the settings are different, re-set them or Auto-Tune controller.
	3. Controller is defective.	3. Replace controller.
	4. Actuator coupling is damaged or defective.	4. Repair or exchange coupling.
	5. Fuel temperature set too high.	5. Adjust set point.