Riello 40F15 oil Burner

MikeH_2

The Riello burner is on a Buderus GE315-7 Boiler. 6 months ago I was called in to repair and get the unit running. I had to replace primary control, nozzle, and electrodes. I cleaned the turbulator disk along with everything else. Recently I got called back to clean and service the boiler again and as you can see from the picture the turbulator needed cleaning again. Can someone tell me what might be causing the carbon build-up and why mostly on one side of the disk?

billtwocase

can be a few things

need more info. What nozzle is in there, what is the pump pressure, what are you combustion results, draft readings-breech and over fire? Start there

icesailor

Scuzz on heads:

What do you have for filters on the oil? Two spin-on's?

I used to find that with plugged up nozzle strainers. No matter how much pump pressure you can show on a gauge, it won't be the same at the nozzle orifice.

To me, it seemed to be that the correct amount of fuel isn't mixed with the air and burned in the primary flame, and because the Air/Fuel ratio is wrong, there is unburned fuel in returning retention secondary air. The diffuser plate isn't hot enough and the oil vapor sticks to the plate. There's enough residual heat to boil off the oil and leave the carbon.

When you pulled out the nozzle jet line, did you notice how fast the oil ran back out of the line? Is it better and faster with a new nozzle?

I don't get to play with dragons anymore. But if I was, I'd be trying a wire mesh strainer on low GPH nozzles with dual Spin-On filters. I'll bet that problem would go away.

Some may not agree with me, but it helped a lot for me when I went to exclusively dual spin-on's on everything.

billtwocase

although there is truth to filtration Ice,

those boilers had other issues regarding cold chambers, draft, etc. I bet it recycled a few times on start up, at least

icesailor

In the Harbor:

They made poor boat moorings on muddy bottoms.

The best part of the installation was the burner. IMO.

Some didn't like the small diameter air tube, but they sure passed a lot of air down the tube. With a LOOOOOOONG flame. Burned the back right out of those short boilers. BUT WAIT!! The solution, the "A" Tubes, were far worse than that boiler.

At least that was my experience.  Even Watts'ys universal nozzle didn't fix them. The Hago or Delavan 70 degree SS or H, or 70 Degree "H" or "B".

The one thing I never figured out a cause for was Whiskers. I didn't see them often but now that I think of it, I don't think I ever saw them after I went to dual spin-on's. I'm getting old. I have to stop this on-line reminiscing.

MikeH_2

Riello Burner 40F15

I thought a picture's worth a thousand words? But if you need more: the Nozzle is a 4.0x60B. Oil passes through a spin-on filter than through a tiger loop.

Pump PSI = 160; 0.5" = overfire; smoke = 0-1; CO2 = 12.8%; O2 = 3.6%; CO = 47ppm; Stack temp. = 469f; Eff = 84.5%; Amb Temp = 47f; and EXA = 17.3%.



Here's another question; Why would a working Power Flame Burner (CI-0) be replaced by the above Riello Burner if it's only problem was a release of soot particles on startup?

icesailor

Swaps:

Trial & Error solution? And the "solution didn't solve the problem?

The first place I'd be looking is at that "0-1". I've never ever seen anything run continuously with ANY smoke.  If you crank the air way open, do you get yellow in the smoke spot? Can you close it to get 0 smoke and to just smoking, then backed off to 0? Sounds like another issue with either the boiler or chimney draft. What are you using to check the draft? Your analyzer? I only trust my Bacharach MZE analyzer. That's the other thing I've seen cause that sooting on the retention head, Too much back pressure in the chamber. Or constantly changing draft.

4.0 GPH? Is that so? Is this a pressure fired boiler? What kind of draft do you have after the restriction plate? Is it enough to scavenge the exhaust? If you have a bad chimney and a lack of decent draft, all kinds of things can go South.

4.00 GPH (if that's what the nozzle is) at 160# is probably over 5 GPH. Is that what the boiler is rated for? What is the boiler max fire rate? What is the burner Maximum fire rate?

I'm also not sure of this because I have never worked on what you are working on, but I believe the listed Maximum GPH rating is based on what a nozzle sprays at 100#.is. So, if you want to spray a 4.00 GPH through a burner with a maximum firing rate of 4.00 GMH, it needs a smaller nozzle at 160#. If the boiler is rated to have a maximum 4.00 GPH firing rate, and you put a 4.00 GPH nozzle in it and fire it at 160#, the boiler should be over-fired. Causing soot because the fan can't get enough air into the fire.  

You might be following someone else's mistake. Go back to basics. Start from the beginning.

The stories I could tell about dealing with situations like this.

captainco

sooting flame cone

If the boiler was overfired the flue temperature would be much higher and there would be smoke at 3.6% O2.

If the nozzle angle was too wide or the nozzle was dirty I am pretty sure the CO would be higher. 

Initially the problem starts at either light-off or shut-down.  It is critical that the CO stays under 100ppm at both.  Shut-down has to be watched for at least a minute or more just to be sure there is not any delayed afterdrip. 

The combustion test while running leaves no clue at all to the problem.  I found that out 30 years ago, when high efficiency oil furnaces were sooting up within weeks and they were left with zero smoke and that was with 20 pumps of the smoke tester.

Overfired, bad nozzle, not the problem!!

icesailor

Overfired:

Some of what you say may be true.

Why was a Powerflame CI-O burner replaced? They aren't known to be burner dogs. Especially commercial burners like that one. Without being there and knowing the whole history, I get back to why was it changed?

I worked on a place that had a Riello dual fire commercial burner. I don't remember the model # but it was some kind of slick. Once I figured it out and had time to get it back right. The previous person had replaced a Carlin 701 CRD that he couldn't figure out how to make it run properly so he replaced it with the Riello. It still didn't run right. He said it was old and you couldn't get parts for it. Which was total BS. He didn't know how to make the Riello run either.

I replaced a Weil McLain 672 or 674 boiler that the only thing wrong with it was it was improperly installed and the internal water gaskets leaked all the time. I replaced it with the newer series, 476 or 478. I don't remember which with a Carlin 201CRD. I knew the chimney had some rumored vague history. It started sooting up. Within 2 months, no matter what. I finally realized that someone had re-lined the 40' X 14"x14" masonry/tiled chimney that fell apart from the leaking gaskets. So, it was re-lined with a "Solid Flue" application of two 8" "Socks, that seriously reduced the size of the 14" X 14" chimney flue. My resolution was to put a Field blower, blowing positive draft pressure into the chimney, pressurizing the entire chimney and the fan made draft. Enough so that I always had consistent draft AFTER the restriction plate that gave it positive pressure. Although it was designed as a positive draft boiler, in this application, it really didn't like a lot of back pressure. When I had good draft, the problems went away.

I've always found that whatever Carlin spec's for their burners, is a really good place to start. I can't remember ever finding that I had to play "Fun With Nozzles" to get one right. And if I found one that was way off by someone else, going back to Carlin Spec's, was the best place to start from the beginning.

And just because it shows OK on a draft gauge, doesn't always mean it is. Especially if it is windy or cold.

Remember, wind velocity is the same as draft. I've spent the best part of my life chasing draft. My iceboat will go 2 to 5 tim4es faster than the actual wind speed because moving through the air increases the apparent wind speed. Another form of draft.

I still want to know the reason that the Power Flame was changed.

icesailor

Another problem:

Here's another suggestion.

How's the make-up/combustion air? That can drive you up the wall. It takes a lot of free and available air to fire that boiler. If you are working on it, and the doors are open to the room, you might have enough air. Close the door and you never know what will happen. Power ventilation fans. Anything that wants to get air from somewhere. If the pressure inside the building drops below the flowing air pressure outside. Mother Nature, who absolutely hates things out of place, will do her best to equalize the pressure. Like back draft the chimney flue.

captainco

Combustion air

Oil burners need about 25 cfm of combustion air per 1000btus and that includes dilution air through the barometric.  Power burners have a combustion air fan that will overcome just about any negative pressure in a building except maybe an exhaust fan right in the mechanical room and most of the time they overcome that while they are running.  However, when the burner shut down, negative pressure will cause the draft in the chimney to disappear.  This will cause the radiant heat in the combustion chamber to migrate back into the airtube.  After a delay, the oil in the drawer assembly heats up and starts dripping excessively.  This can be seen by watching the CO after shutdown.  This oil squirts onto the flame cone and starts to carbon it up. 

Another problem that causes impingement on the flame cone is two-pipe oil lines.  This causes pulsation I the burn and again impingement on the flame cone that doesn't show up until the burner shuts down and the CO rises excessively.  Tiger Loops and two-stage pumps handle all lifting issues and loss of prime issues.  Od course loss of prime is not something that should be considered normal.

icesailor

Draft & Fire:

A burner, fired at the end of its range (like a Carlin EZ-1, .50 to 1.65 will not run any near perfectly at 1.65 GPH that it will at 1.50 GPH. Similarly, a EZ-2 will run better at 1.65 GPH per hour than the EZ-1 because of the bigger fan and higher available static pressures. A EZ-1 fired at 1.65 GPH with a dirty or worn fan cage(dirty or worn vanes) will not develop the static pressures that a new on will.

I have seen a Tjernlund SS1 Sideshot in a confined space that calculated OK for make up air. But the Side Shot needed more air to create its draft and cooling air. SO, during Post Purge, it sucked air back through the burner tube to the point that it was hot enough to burn your fingers. There was not enough make up air. There were two doors into the crawl space. I installed two 12" RC draft controls in backwards in the doors. When the burner and Side Shot would start, both RC's opened to let equalizing air into the room.

What you say may be true most everywhere. But not everywhere.