Ok,

This one has me stumped...

Furnace runs fine, every once in a while it will trip the reset. Hit the button, fires right up like nothing was wrong.

After this happened a few times I...

1. Changed the nozzle.

2. Adjusted the electrodes.

3. Bled it really good in case the was an air bubble in the line.

4. Cleaned the CAD cell that is only 6 mo. old or so.

Seems to be running clean at the nozzle, not white (lean) or black (rich).



Seems like I have good spark at the springs, I don't have a line pressure gauge but when you bleed it, It comes out in full force.


any ideas?

 

In a perfect world you could verify the nozzle's in fact getting 100psig.

When you say you adjusted the electrodes, are you in fact setting them according to the burner's manufacturer's recommendations?

How's the draft?

 

Yes,

I adjusted them to the manufacturers specs. In fact I have it written on the side of the boiler.

I don't have a draft gauge either but this only has 8 feet of 8" smoke pipe with a barometric damper. It's in a greenhouse so it's nothing fancy.

 

Naturally, they run much better when up to full operating temp. Having said that, is your nozzle small enough that it barely supports your heating needs on the extreme days? The goal being the nozzle's not so big that the system short-cycles needlessly.

 

Long story but right now this particular greenhouse is a 96' tarped at 32'. It originally had a 1.65 GPH nozzle cut it back to a 1.10 GPH and adjusted the air band accordingly. I have plenty of BTU's with the 1.10 but for some unknown reason she kicks out for no apparent reason here and there.

Last night she kicked out at 1AM and 3:45AM (I have an alarm that calls me when the temp is low). Sucks working on an oil furnace at 3 AM when I should be sleeping especially when you hit the reset and everything seems to start normal.

 

With technology changing so fast, is the barometric damper adjusted for the new (reduced) flow (if adjustable at all)? That short stack may not really be providing much if any draft.

 

Update: called the manufacturer and they had a few suggestions.

Today I put a new transformer and new cad cell again in case the last one was bad.

So far so good. It's running fine and we will see about tonight.