[beemergary]

Furnace lights and about 8 seconds later goes out and about 3 seconds later comes back on and everything is normal. Earlier there was a contact problem between transformer springs and electrodes but fixed that.

[rwfisher]

Mine was similar due to flame detection issue. Photocell cleaned and igniter spacing adjusted…

[beemergary]

Originally Posted by rwfisher

Mine was similar due to flame detection issue. Photocell cleaned and igniter spacing adjusted…

Did that. Think my photo cell takes 45 sec. to not see light and then sends signal to the brain box which shuts down furnace and needs a reset button pushed. Thanks

[GtoFM]

New identical nozzle and pull the unit to make sure it is clean, especially if it is a flame retention burner. May be time to call a pro.

[Elarson]

Another possibility:

The pump has some sort of internal check ball to prevent the oil from draining out of the suction tube and back to the tank. If that valve is leaking, the oil suction tube gets some air in it. The first 8 seconds of running is off the residual oil in the pump. 3 seconds of pulling fresh oil from the tank and then away you go.

I've had this before and replacing the pump was the cure.

Eric

[ts3189]

Dirty flame sensor. Lightly run 3m scrubby pad over it to clean.

[beemergary]

Originally Posted by Elarson

Another possibility:

The pump has some sort of internal check ball to prevent the oil from draining out of the suction tube and back to the tank. If that valve is leaking, the oil suction tube gets some air in it. The first 8 seconds of running is off the residual oil in the pump. 3 seconds of pulling fresh oil from the tank and then away you go.

I've had this before and replacing the pump was the cure.

Eric

Checked pressure and was down so replaced pump. I have a return line and no check valve in pump. Fixed problem. Glad it wasn't a leak in the supply line that's 3 feet under ground.