Smoking boiler

mike212

I have a recurring problem that started about a week after my oil boiler was serviced. This scenario that I'm going to described has happened two times now. The oil company is on the way again, but they were at a loss last time trying to figure out the issue so hoping you guys have ideas here.

Background... We have steam heat with an oil burner. There is a thermostat on the side and we keep it at around 130 in the summer just so the boiler cycles on and off and doesn't dry out - recommendation of a few different people.

1) We smelled a very strong unburned oil smell coming from the boiler room area. The smell spread through the house. This isn't normal.
2) I checked the boiler and don't see any drips of oil anywhere on the floor, on the unit or the surrounding area. The tank looks and smells fine too.

3) The first time this step occurred shortly after the smell, this time I waited a day until the smell was gone before doing this step... I attempt to turn on the boiler by raising the thermostat on the side. It fails to click on. I press the red reset button and it immediately kicks on, but unusually smoke is being pushed out of the the flap on the side of the vent to the chimney. The flap seems to be acting weird as it appears there is air being pushed out instead of being drawn in.
4) I see this smoke coming out and immediately turn off the boiler switch.
5) Smoke begins to pour out of the top of the boiler cover and a few spots in the front.
6) The quantity of smoke actually increases over the next minute and continues for about 5 minutes until it declines in quantity.
7) After the initial minute of smoke where it appears to be coming from a bunch of places, the main smoke is coming from the Beckett unit at the bottom front of the boiler with most of the smoke coming out of the air inlets.

Last time this happened, about 2 weeks ago the oil company came looked through everything, but couldn't find something that would clearly cause the issue. They are on the way again now today. Any ideas on what I can have them look for? The strong unburned oil smell that preceded this has to be related to this.

See photo and video of smoke here...
https://imgur.com/a/g33YCs2

Steamhead

There is unburned oil in the firebox. When it ignites, you get the smoke.

My first reaction is an ignition failure. Since the primary control (gray box with reset button) lets the burner run for 45 seconds before shutting it down if it doesn't light off (this is called "trial for ignition"), the burner will spray oil into the firebox for that long. If it ignites on the next try, you get the smoke. This type of primary also does not shut off the ignition after the burner lights off, which causes extra wear on the ignition system.

We like to upgrade our customers to a primary with a 15-second trial for ignition, which also shuts off the ignition after the burner lights. We also add an oil delay valve, which holds the oil back for a few seconds until the fan and pump pressure come up to normal levels and the ignition spark is established. Then it opens, and you get a nice, clean light-off. When we go back the next year, there's hardly any cleaning to do.

mike212

So the tech said I just needed a new nozzle and that's it. He said sometimes they get bad nozzles and maybe the last one installed was bad (would have been last 2 installed were bad since the nozzle was changed on 6/30 and then again 10 days later and now again). He said there are no obstructions, the pressure is good and so it couldn't be anything else. Unfortunately I don't have much confidence that is the case.

@Steamhead, thank you for your take. Can you detail more about the hardware you recommend that provides the 15 second trial for ignition and shuts off after the burner lights and the oil delay valve? If this happens again I think it makes sense to try this.

HVACNUT

The boiler is plugged. It must be brushed and vacuumed. Same for smoke pipe, chimney base, and combustion chamber. Then a combustion analyzer, smoke tester, and draft gauge is needed to adjust and dial everything in.
Also consider upgrading the primary from 45 seconds to a 15 second model.

Steamhead

@mike212 , that "tech" should not be in the business. Where are you located?

I agree with @HVACNUT that the boiler probably needs to be cleaned and the burner tuned, since poor combustion caused by these "puffbacks" does create lots of soot. You need a service company worthy of the name.

The upgrades I mention should only be done by a competent service person.

mike212

@Steamhead I'm in Westchester Country New York. I do think the man that came this time was a bit quick. I'm not certain that he did all or any of the things HCACNUT mentioned, but I'm also not certain he didn't. The system was fully cleaned and tuned twice in the last 30 days so hopefully he did do these things it was just quicker this time.

I'm reading about the 15 second model and the oil delay valve, those sound like good ideas.

mattmia2

There should be a report from the combustion analysis that was done both those times if it was actually done and done properly

Steamhead

@mike212 , go here. I'm not familiar with NY geography, but you should be able to find someone who knows their stuff:

https://heatinghelp.com/find-a-contractor/state/NY

mattmia2

I think @JohnNY is in that area. If he doesn't do oil burner work he probably knows who does.

Steamhead

mattmia2 said:

I think @JohnNY is in that area. If he doesn't do oil burner work he probably knows who does.

Second that.

Jamie Hall

Third that. And I will add -- first, it takes hours, not minutes, to clean a boiler's fire side, and yours needs to be cleaned -- if it didn't before, it surely does now. Second, having smoke come out of the damper on the breaching suggests to me that something is very much amiss in the chimney or flue, as well as problems in the boiler. That needs to be checked.

mike212

Jamie Hall said:

Second, having smoke come out of the damper on the breaching suggests to me that something is very much amiss in the chimney or flue, as well as problems in the boiler. That needs to be checked.

I appreciate the feedback. I did ask about that - why is there smoke backing up out of the damper? He said that was just because there wasn't good combustion - since oil had sprayed all over - there wasn't good combustion to create a draw to pull in air and the smoke up the chimney. Is that valid?

As I watched the smoke, very little came out of the damper. It was just a couple small puffs initially and then after that everything was coming from either the boiler or the Beckett unit itself.


I'll note that it does seem to run fine now but I'm not confident it will continue like this. It will work until I smell unburned oil and then I assume it will repeat.

mike212

One more idea just came up as I think about this. The problem may correlate with a recent fill of my oil tank. The tank was filled not long before the first time this issue occurred. I have something called a "smart oil gauge", which is a device added to the tank that tells me the level. Well yesterday just as I smelled unburned oil, the gauge gave me a notice of a fill and then it did it again a couple hours later. I just got another notice of a fill now but its hard to tell what smell I have since the house is still recovering from the smoke. No one has refilled the tank since about a month ago.

Anyway, is it possible the tank is overfilled, creating these false fill notices on my gauge and also possibly pushing oil into the burner just from pressure? I don't know if this is plausible but the alerts and timing of the last fill all work towards a theory around this.

Dave Carpentier

I had an oil solenoid valve in the burner assembly start to get lazy. I suspect when closing, it dribbled oil. On restart, there would be some extra entertainment.

Perhaps when it was serviced, some crud got into the line and past the screen filter into the pump (and into the solenoid) ?

https://www.beckettcorp.com/support/tech-bulletins/oil-solenoid-valves-are-useful/

Steamhead

If you add a solenoid delay valve to a standard fuel unit such as a Suntec A2VA-7116, there is less chance of this. The A2VA-7116 has a built-in mechanical cutoff, so the delay valve would provide some redundancy.

Steamhead

mike212 said:

One more idea just came up as I think about this. The problem may correlate with a recent fill of my oil tank. The tank was filled not long before the first time this issue occurred. I have something called a "smart oil gauge", which is a device added to the tank that tells me the level. Well yesterday just as I smelled unburned oil, the gauge gave me a notice of a fill and then it did it again a couple hours later. I just got another notice of a fill now but its hard to tell what smell I have since the house is still recovering from the smoke. No one has refilled the tank since about a month ago.

Anyway, is it possible the tank is overfilled, creating these false fill notices on my gauge and also possibly pushing oil into the burner just from pressure? I don't know if this is plausible but the alerts and timing of the last fill all work towards a theory around this.

You might investigate this by noting how low the gauge was when they filled the tank, and seeing how many gallons were added. This would give you at least a rough idea.

If the tank has a proper vent, it should not overpressurize.

rick in Alaska

The fuel level in the tank will not cause the issue you are having. If your tech is leaving it when there is still smoke coming out, then get a new tech. This is totally wrong, and dangerous. If that burner tries to fire with that vapor present, it could explode. When that diesel is in the vapor stage like that, it is very explosive.
There is some kind of ignition issue happening here. Air in the fuel, dirty nozzle, bad fuel line connection, fuel pump, improper set electrodes, bad ignitor. Your tech should be checking all these items and not leaving until it is right. Did they use a smoke tester and combustion analyzer? I am betting no.
Rick

captainco

I have never heard of operating a boiler in the summer to keep it from drying out. Someone is pulling your leg. If there is excess oii, impingement, after-drip, bad nozzle, air etc. a trained contractor could detect it using a combustion analyzer and watching the CO reading when it lights, while it is running and when it shuts down. Without it everyone is just guessing!! Unfortunately I doubt there is anybody in your area that knows how to do that.

Do not run your boiler if you don't need heat!!

Maybe someone will look at the chart I attached and do some real troubleshooting!

Steamhead

@mike212 , does your boiler also provide hot water to your faucets?

mike212

@Steamhead no, the boiler is purely for winter heat.
@captainco the logic I heard was keeping the temperature of the boiler at something low, like 130 degrees would prevent any gaskets from drying out, but I wonder if there are even any rubber gaskets to worry about . I certainly prefer to keep it off to avoid heating my basement in the summer for no reason so will give that a shot.

I've been gathering all your thoughts and trying to do some reading so that I can better understand the response of the oil company when I present these ideas. My plan is to call the oil company on Monday and ask to speak to the manager where I can direct questions about whether diagnostics were performed, whether it was properly cleaned after the latest smoke issue, thoughts and pricing on adding the oil delay valve and swapping my 45 second primary for a 15 second one, and all the other issues and ideas everyone here has so kindly presented. I really appreciate every one of all your responses!


One further idea... is keeping the boiler running (set to an abnormally low thermostat temp of 130) through the summer causing or exacerbating the problem of oil over spray? I can recall from prior summers that the primary would need to be reset occasionally in order to get the boiler on but this would only happen in the summer. In the winter it never required a reset. (In prior years I never had the issue of smoke though either so something is different). Maybe the very short runs required to get the boiler up to temperature are too short to burn off the oil sprayed and it builds up? Possibly just keeping it off for the summer might resolve that part of the issue?

rick in Alaska

Hm. More information.

" I can recall from prior summers that the primary would need to be reset occasionally in order to get the boiler on but this would only happen in the summer."

Makes me wonder if there is a vacuum leak in the line that is letting the fuel drain back a bit, or introducing air. In the winter time it is running almost full time, so the burner is not off long enough to build up an air bubble.
As far as running the boiler and keeping it warm, if someone put dielectric unions on your system, and I hope they didn't, then they are known to dry out and start leaking when they go cold. If you bump the union in this condition, you can break the rubber gasket that is now like plastic, and then you will have to replace it. However if you leave it alone and get the boiler heated back up, then it will usually seal itself back up. Not all unions will leak like this, but in my experience, if it has been on for a long time, this is what happens.
Rick

captainco

If I am an oil company I would certainly recommend keeping it because they need the income. But unless you have deep pockets, turn it off. How does a fire make things wet?

captainco

It is my firm belief that two wrongs don't make a right!!

Steamhead

The boiler in question is a Weil-McLain SGO. This type of boiler does use gaskets between the sections. But our customer base has quite a few of these boilers, none of which stay hot all the time, and they don't seem to have gasket-seal problems.

@mike212 , what is the green circulator pump for on the left side of the boiler?

mike212

@Steamhead , that green pump is connected to a baseboard hot water line that runs in the basement for heat in the main basement room. I very rarely turn that on because 1) its usually warm enough without it and 2) I don't circulate the water through the baseboards when the boiler is steaming because there is nothing to prevent the boiling water from circulating through the baseboards. If I turn it on, I turn it on for brief periods when I know the boiler hasn't just heated up to produce steam.

I added a few photos from different angles to the original image link: https://imgur.com/a/g33YCs2

mattmia2

mike212 said:

@Steamhead , that green pump is connected to a baseboard hot water line that runs in the basement for heat in the main basement room. I very rarely turn that on because 1) its usually warm enough without it and 2) I don't circulate the water through the baseboards when the boiler is steaming because there is nothing to prevent the boiling water from circulating through the baseboards. If I turn it on, I turn it on for brief periods when I know the boiler hasn't just heated up to produce steam.

I added a few photos from different angles to the original image link: https://imgur.com/a/g33YCs2

There should be a bypass in the hot water loop to bypass some of the return water in to the inlet of the circulator to keep the temp a bit under boiling.

mattmia2

rick in Alaska said:

Hm. More information.

" I can recall from prior summers that the primary would need to be reset occasionally in order to get the boiler on but this would only happen in the summer."

Makes me wonder if there is a vacuum leak in the line that is letting the fuel drain back a bit, or introducing air. In the winter time it is running almost full time, so the burner is not off long enough to build up an air bubble.
As far as running the boiler and keeping it warm, if someone put dielectric unions on your system, and I hope they didn't, then they are known to dry out and start leaking when they go cold. If you bump the union in this condition, you can break the rubber gasket that is now like plastic, and then you will have to replace it. However if you leave it alone and get the boiler heated back up, then it will usually seal itself back up. Not all unions will leak like this, but in my experience, if it has been on for a long time, this is what happens.
Rick

I suspect the burner isn't set up right and with the change in draft of the vent between summer and winter what lights off in winter sometimes doesn't in summer.

Dave Carpentier

In the video, where it zooms into the area above the pump (0:07), does it look like marks to the right of where the nozzle depth bolt is ? Are they just dirt marks, or is that where it's supposed to be locked down at ? Head and nozzle relations vary by design, but mine is set quite a bit further forward than that one.

captainco

The fact that the barometric is closed and trying to push out might indicate some negative pressure problem. On my diagnostic chart that would be delayed afterdrip causing the smoking out the burner. My chart doesn't discuss combustion air or venting issues directly but the CO numbers are a big clue. I wish everyone knew how to diagnose oil burners using 21st century diagnostics not 19th century!

Steamhead

mike212 said:

@Steamhead , that green pump is connected to a baseboard hot water line that runs in the basement for heat in the main basement room. I very rarely turn that on because 1) its usually warm enough without it and 2) I don't circulate the water through the baseboards when the boiler is steaming because there is nothing to prevent the boiling water from circulating through the baseboards. If I turn it on, I turn it on for brief periods when I know the boiler hasn't just heated up to produce steam.

I added a few photos from different angles to the original image link: https://imgur.com/a/g33YCs2

That explains why the boiler is being kept warm. But it doesn't have to be. I've seen this before.

The R845A relay has a second contact in it. It should be wired to start the burner unless the aquastat is satisfied. That 24-volt circuit should go from one T terminal on the primary, through the R845A relay contact, through the aquastat and back to the other T on the primary. This way, if only the baseboard loop is calling for heat, the boiler will not get hot enough to make steam.

If the baseboard loop is at the same level as the boiler room floor, there is enough static height in the boiler water to keep it from boiling in the baseboard. But a bypass like @mattmia2 suggests is a good idea as well.

captainco

I am lost! I want to know why running a boiler at 130 degrees on a 95 degree day outside is necessary?

Steamhead

captainco said:

I am lost! I want to know why running a boiler at 130 degrees on a 95 degree day outside is necessary?

Somebody screwed up.