can the wrong nozzle size cause damper to blow off on oil-fired boiler?

mrblint

I changed service companies this past year. Twice now, after they did the annual service on our Buderus G115 with Riello burner, there has been a problem. Woke up the next day and there was no hot water. Had to manually start the burner with the button on the front. A different tech came back and re-tuned everything and it seemed to be OK, never had to restart manually, but the damper has blown off twice now, and they are coming back again this afternoon. I notice from the little container they left that they installed a .60x80B nozzle but there's a tag on the Riello that says for the Buderus G115 it should be .65x60A nozzle. Could that difference be causing delayed ignition?

Jamie Hall

Not by itself. However, the nozzle angle and pattern change may have affected how the ignition electrodes interact with the spray pattern, and without adjusting that — and all the other associated adjustments, using test instruments, that could be a problem.

yellowdog

You need to go back to your last service company. These ones are clueless.

Intplm.

And, if at all possible make sure the damper is installed/secured correctly.

mrblint

Jamie,

Could you please briefly explain, not in detail, just so I have a general sense of what is involved, in the adjustment of the ignition electrodes? The second tech did have those electrodes out and was looking at them, but there wasn't any sort of measuring gauge involved. He just eyeballed them. He did do a smoke test and hooked up an analyzer, something like a laptop, to measure efficiency and tweaked the air intake a little.

mrblint

yellowdog

The old service company used to be excellent. But they went downhill and now they don't have any "depth on the bench" as far as oil burners are concerned. They are getting out of the oil burner service business. Natural gas is not an option for me since the gas company never installed it on my (short) block because my house was built later when someone split their corner lot, and mine is the only house on the block that is not on a street corner with access to the cross-streets where the gas-lines are. Gas company said they would run the line for $35,000.

EdTheHeaterMan

I got this @Jamie Hall

Electrode / ignition adjustment is important on an oil burner.

There are several factors when it comes to proper oil burner adjustment. the first part is to make sure that the electrodes of the ignition system are not too close to the oil spray. This could cause carbon from the oil to form a bridge across the electrodes, leaving no room for a spark. Next you need to be sure that the electrodes are not too far away from the oil spray. That will cause the spark to not reach the oil spray and no ignition or delayed ignition will happen. Delayed ignition means that there is more oil in the combustion chamber by the time the spark reaches the oil spray and causes a larger that normal expansion of the flue gasses to happen. This larger than normal expansion in the chamber can push a large amount of pressure in the vent pipe and cause the barometric draft control to pop out of the opening and end up on the floor.

The next thing is to have the correct air to fuel ratio. If there is too much air, that excess air can blow the flame out while it is trying to ignite. that is anothe reason for delayed ignition. A good oil burner tech can easily make the correct adjustments. A rookie may still need to learn what the wrong adjustments can result in.

EdTheHeaterMan

As you can see from these illustrations published by Delavan Nozzle, the different spray angles of nozzles will cause the electrode to be closer or further from the oil spray.

So when the nozzle angle was changed, the recommended electrode adjustments for a 60° may not be appropriate for the 80° spray

This is a Riello recommended electrode setting specification based on a 60° nozzle, along with the air setting for the turbulator setting. I believe that a 60° spray pattern nozzle works better in most Riello burner applications.  Not ALL but in most, I would go with the boiler manufacturer’s recommendations in your case

EDIT:

By the way, I have never seen any other boiler or furnace manufacturer give such accurate settings on the burner air adjustments as I have seen with Riello. When you put all the settings exactly as recommended in the literature including Nozzle Specification, turbulator setting, air gate setting and fuel pressure, you are almost exactly where you should be for peak efficiency. Minor adjustments on any of the settings seem to always become less efficient on my combustion analyzer. This is a company that really knows what is the best way to set up their oil burners. If the technicians would only take the time to read the instruction manual, there would be a lot less call backs for improper adjustments.

YOU SHOULD ALWAYS VERIFY YOUR SETTINGS WITH A COMBUSTION TEST.

HVACNUT

Riello specs a .65 60°A or .65 60°B at 190 psi for the G115/4. No 80° angle mentioned.

The draft regulator needs to be secured with screws. Even if it's not, it shouldn't blow out. Combustion needs to checked and adjusted with an analyzer, smoke tester, and set draft for -.02 breach with 0 to slightly positive over fire.

EBEBRATT-Ed

Just need a burner tech with a brain and the burner/boiler manual and an analyzer. Do you have an inside or outside oil tank? 1 or 2 oil lines?