Waste Oil furnace, burner won't run

bellerlogging

I have an Energy Logic waste oil furnace. Oil preheater gets hot, fan runs all the time, but burner never tries to run. Suggestions?

EdTheHeaterMan

They can be tricky. When was the last time you had the burner, nozzle, pump, and preheater taken apart and cleaned? I did service on 4 different waste oil heaters and when the customer found that I could work on them, each one had never had the recommended maintenance done. It would take about 4 hours to take every oil handling section of the system apart, remove all the sludge and gunk that was inside those parts and then put it all back together. once you get all that stuff clean… they work great.

What is the model number of your Energy Logic? 140, 200, 360 or the "small shop" 75 model?

EdTheHeaterMan

Thank you for your PM response. After looking closely at the Energy Logic EL 200H manual, (I had a customer with the EL140H) it appears that the primary control gets a thermostat signal to start the fuel pump, combustion fan, and the ignitor only if the preheater is on and the fuel temperature is at or above 140°. You indicated that the preheater is on and you can feel the heat from the preheater. So there are several possibilities

1. The oil is not over 140° or the temperature sensor is defective and the fuel temperature is not detected.
   1. You need to be sure the oul temperature is at or above the 140°
   2. You can check the oil temperature sensor to see if it is working by placing. temporary jumper wire on the sensor to bypass the sensor.
2. The thermostat has a problem or the thermostat wires are not connected
   1. see if the thermostat batteeries need to be replaced
   2. check the wire connections from the thermostat to the T T terminals on the primary control are not loose or disconnected
   3. You can place a temporary jumper wire from T to T on the primary control to see if the burner will start.
3. The Cad Cell flame detector is defective in sone fashion.
   1. Remove one or the yellow wires from the F F on the primary control terminals.
      1. If the burner does not start then the problem is elsewhere
      2. if the burner starts then the flame sensor circuit is shorted and the primary control will not start. Go to step b.
   2. Open up the burner and remove the cad cell eye from the holder.
      1. Put the burner back together without the cad cell in the holder.
      2. Put the yellow wire back on the primary control and turn the burner on
         1. if the burner starts then the cad cell eye is defective
         2. if the burner does not start then the harness, and wires are defective and may have been pinched by a metal cover or hinge on the burner assembly causing the short in the flame signal circuit. repair or replace as needed.
4. Before you leave this furnace, whether fixed or still needing service, remove any temporary jumper wires and restore the furnace and burner to the original status. This way a different service technicial will not need to find out the hard way that you left a safety device disabled.