OT: Sorta - Shop Furnace

[Patrick Fischer]

My shop furnace is an old Sanberg oil burner. I ran out of fuel last week and had the oil company fill the tank today. {ouch, but that's another story} Problem is that the furnace won't burn. I have the thermo at 60 (it's low

50's in the shop) and when I hit the reset button the burner motor starts and runs for 60-90 seconds and stops. I can get the blower going by moving the switch to manual from auto but it just blows cold.

I bled the line by opening two screws, one on top and the other at the bottom of the oil inlet thing. Lots of bubbles then clear red fuel. closed the bottom and then the top. Still no change. Thoughts? Does this have a pilot light? I wouldn't think so but.....

Any help would be appreciated. How can a guy make sawdust at 52 degrees afterall (ducking).

[Tom]

My brother in law services oil burners and he really chewed my A_S last year for pushing the red reset button several times when my furnace in the garage wouldn't start. When he finally got there to fix it, it damned near blew because of all the oil that had accumulated in the burner pot from my repeated pushing of the reset button. Now, as for ideas on the problem..first time I had a problem, it needed a new burner nozzle and the ignitor gap adjusted. A few months later, it wouldn't restart after burning for awhile. Problem this time was the control box for the ignitor that sits on the motor/pump. Tom.

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[Patrick Fischer]

Thanks Tom. I had a feeling I was squirting oil into the pot with no ignition source. Guess I'll call the service guy...

[Luigi Zanasi]

On Wed, 30 Mar 2005 20:07:06 -0800, "Patrick Fischer" scribbled:

52 degrees is quite warm by my standards. But when it happened to me, I sucked some gunk from the bottom of the tank and it clogged up the jet. The service call is a good idea.

Luigi Replace "nonet" with "yukonomics" for real email address

[Patrick Fischer]

Turned out to be a plugged nozzle.Removed the fuel line and with a short blast of compressed air..HEAT!!

Thanks.

[fredfighter]

For future reference furnaces typically have a flame detector. That is a basic safety device, either a photocell or a themocouple, that as the name implies, detects a flame. If a flame is npt detected within a few seconds after the fuel pump comes on the fuel pump is shut off. This prevents a dangerous accumulation of unburned fuel in the furnace.

Each time the reset is pressed and another attempt made to start the furnace more fuel squirts in.

That's why one should not use the reset more than once or twice befor trying to find and repair the problem.

I think oil burners use a thermocouple and gas burners use a photocell.

[George]

Think it's the opposite. Gas use confined combustion chambers compared to oil, and the flame is more blue. Big orange flames from atomized oil into a large firebox favors the "eye."

[fredfighter]

photocell.

compared to

I'll defer to your expertise. The orange color is produced when carbon monoxide combines with oxygen to produce carbon dioxide and free carbon. It's the atomic carbon that emits the orange photon and produces soot.

I was only guessing that since gas burns cleaner, which is why the flame is blue, it would be less likely to soot up the window.

An optical flame sensor is better than a thermal one because it can detect a flame immediately, a thermocouple takes time to heat up.

[Greg O]

Oil uses a photocell, pretty much exclusively. Gas uses ether a thermocouple, (old technology), or "flame rectification", where a small current is actually run through the flame and a circuit board measures the current. Yes for the non-believers, flame will conduct electricity! The current flow it measured in microamps, usually .5-1 microamp is sufficient to satisfy the circuit board. Any less and the gas valve is closed. Greg

[J. Clarke]

Not only will it conduct, you can use a flame as a speaker. At one time it was a fairly popular science-fair project.

[George]

It may be able to detect immediately, but it has a built-in delay because the ignition provided by the points doesn't necessarily light the atomized stream right away. 20 seconds on my burner, for example. You have to set the air mix carefully, or you won't get the proper color flame, and the damned thing just won't stay lit.

Soot on the pilot thermocouple was a pretty common fault with gas in the old days.

[Robert Bonomi]

Not only will a flame conduct electricity, you can *modulate* the electricity flow, and use the flame as a _speaker_. The sound reproduction fidelity is incredible.