View Full Version : Oil furnace turns itself off after 10 seconds, turns on, then repeats the process?

11-12-12, 08:58 PM

Our oil furnace seems to have a life of its own...turns off after 2-10 seconds after being on, then after turning off it will turn itself back on...2-10 seconds later, it'll turn off. I keep hearing a click each time. Anyone have any insight on this? :(

11-12-12, 09:04 PM
I don't know much about oil burners, but do some searching here. There is a wealth of info. It helped me diagnose and repair my gas forced air furnace. Similar problem to yours. Turned out to be nothing more than a loose corroded wire.

11-12-12, 10:02 PM
When did you last service the burner ?
Forced hot water, or hot air ?

11-12-12, 10:49 PM
Thanks for the link, I went to it but it didn't help too much :(. Service was done about 3 years ago I believe. How do I tell the difference between hot water and hot air?

11-12-12, 11:26 PM
They have a sensor telling the controller if there is flame or not, no flame = turns off pump. the clicking you are hearing is prob the ignitors trying to start the flame. After about 10 seconds of no flame it will stop.
To me it sounds low pressure from a plugged screen and or filter, but ignitors could need replaced, maybe bad pump, outside shot it's the sensor. Find the model and download a manual if available, also check the pump brand and model and download that also.
I will assume you have enough fuel?
Oil furnaces can be a real sob to fix unless you understand them well. Seems mine would always act up when it was really cold and midnight on a Saturday so I got good at fixing them.

11-13-12, 09:19 AM
JUST went through this 2 weeks ago - turned out to be a bad ignition transformer.

Yep ^^^ - the burner has a CAD (fire) eye that shuts down the burner/pump if no flame is detected. Be careful - many unsuccessful startup attempts will put a right fair amount of fuel oil in the burner ceramic pot.

11-13-12, 09:25 AM
Hope you're both right, Rod and Sub. I think it could be that also. I've turned off the emergency switch last night (sucked since it's freezing now!) to wait for a pro to come look. Any idea on what this repair cost could look like?

11-13-12, 07:01 PM
Depends on your local labor rates, but there will be a minimum service call charge plus time - so, if your ignition transformer is bad and the tech troubleshoots the system and also installs a new oil nozzle you're looking at $400 - $550.

11-13-12, 10:48 PM
3 years is a long time betwen services for an oil burner; I'm guessing you have FHW heat .
Service the sucker every year .
HHO is not the cleanest stuff; filters get clogged etc .

11-14-12, 12:02 AM
Thank you very much all! The service person came and looked at it, it looks like there was a problem with an electrical relay to and from the safety switch which caused it to trip almost immediately after it started, causing the On/Off effect that was happening.

Other than that it was all well and good. Service person switched out the relay and some other part I couldn't recall at this time, total cost was $175.

11-14-12, 08:52 AM
We use a Carrier heat pump for primary heat and, instead of electric coils in the air handler, the system is also an oil furnace, forced air. The rig is called a "fossil fuel kit": The turnover is set for 25 - the heat pump shuts down and the system shifts to oil heat. It's actually cheaper (less expensive, even now) to burn fuel oil or diesel (same stuff) than it is to use electric coils (think 3 stove burners) for backup heat supply. I actually use so little fuel oil (woodstove works just fine) that I fill the 550 gallon underground tank each spring with trips to local gas stations when diesel is lower in price. One of the trucks has a 50 gallon diesel tank and pump in the bed, so the refills are no trouble because the system uses less than 100 gallons/year. I use diesel stabilizer and BioBor from West Marine to keep the fuel clean and fresh.

Anyway, every fall I change the oil burner fuel filter and set the electrode gap. The previously posted transformer glitch was the first actual parts replacement service in 25 years.