Gas and Oil Home Heating Furnaces - Problem With Old Beckett Burner

Not sure what model, but it's over 20 years old. Forced hot air, no A/C, just heat, not even hot water. Normally this unit runs flawlessly. Last winter the primary controller went and was replaced. No problems after that. Just recently the burner nozzle and the system filter were replaced. I also just replaced the thermostat (one of those old Honeywell circular types that one rotates) with a digital Honeywell 230B. Simple two wire connection. The problem existed before and after replacement of the stat and started about two weeks ago. The stat was replaced for the convenience of the programmablity, but I thought I may as well rule that out. Let me point out that this unit is located in an auto repair shop. I usually leave the stat set at 60F during the day and the burner runs fine all day long. If I turn it down to 50F when I leave to go home the reset button will have popped by the time I return in the AM. Set the stat back to 60F, push the reset button and the burner ignites, runs for maybe 10 seconds and then the reset button pops again. Resetting the button a second time will now allow the burner to run all day as if nothing is wrong. If I leave the burner set at 60F all night it continues to function normally all night. It is only when I set the stat down to 50F that this problem occurs. And it did it with the old stat too. Any ideas would be appreciated. I have been an automobile mechanic for 37 years so I am no stranger to working with hand tools. I have a digital volt/ohm meter and know how to use it.

Being in a shop, I am presuming this is an overhead heater?
Two lines from tank to furnace? I am suspecting the long off time is allowing fuel to drift back from the burner. Check ALL of the fittings from the tank to the pump.

Ran into the same problem at a factory that called us in. :thinker: All we did was install check valves on the line (specially made for fuel oil) and changed all the compression fittings to flares and PRESTO! :thumbup: They though we were magicians since they had this problem for 10 years and nobody ever fixed it!

Goes to show how simple a fix can be!

Like I always say: "Keep it simple"-----most problems have simple solutions.

Good luck,
Charlie:coffee:

The check valve in the supply will probably mask any poor connection at the pump that allows air to enter but should not be necessary. Don't put a check valve on the return line. A tigerloop may be a better modern solution. Weak ignition will also present itself this way. As will some burner adjustment problems.

Ken