Oil burner delayed flame ignition

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by tviapiano, Jan 4, 2007.

  1. tviapiano

    tviapiano New Member

    Messages:
    17
    Location:
    Massachusetts
    Hi.
    Ever since my annual inspection/cleaning by my oil company a few weeks ago, my WM oil-fired boiler sometimes has a delayed flame ignition. I can hear the oil pump/blower start, the power assist blower on the smoke stack start, but the flame can take between 1 and 10 seconds to come on. It doesn't happen everytime it starts and it doesn't seem to matter how long between cycles.
    Does that mean that un-burned oil is being sprayed into the combustion
    chamber? Is this normal or should I call them back to check this?

    Also, after buying the house (about 2 1/2 years ago) I noticed that the plumbing to the tankless coil is actually reversed: the cold supply connects to the fitting labeled "hot" on the tankless and vice-versa. Someone told me that having it connected that way probably only makes it slightly less efficient for heating the water. Is it worth it to reverse it to how it should be?

    Thanks for your help.
  2. joe in queens

    joe in queens New Member

    Messages:
    36
    I'd bring 'em back before the thing doesn't light off at all... like when it's 20F outside. Delayed ignition can also be somewhat dangerous. After the delayed ignition, does the unit then light off hard, rumble or make any unusually loud noises?

    One thing that should be noted, many burners have a "pre-purge" function, where the burner runs up for 15 seconds to build pump pressure and establish proper draft for smooth and clean light offs. No oil is pumped into the chamber during pre-purge. And pre-purge times are always consistent - so pre-purge doesn't appear to be the issue in your case.

    Did the oil service company provide any tune-up specs? Things like stack, smoke, CO, efficiency, draft? Did you notice if they used testing instruments to adjust the burner? They should have. If they didn't bother calling them back, call a real pro.

    Is this unit a power venter? In other words no chimney and the unit vents on the wall outside your home through PVC pipe? That second motor you described starting up sounds like a draft inducer, but I wanted to make sure it's not a power venter.

    I'd correct the flow on the coil according to manufacturer spec. The piping change shouldn't be a big deal in terms of time, materials or cost. A pro could do it in 15-30 minutes.
  3. vaplumber

    vaplumber Guest

    Also if you have a cartridge (or sock, as I call them) type fuel filter such as a general 1-A or 2-A, and your servicer replaced only the filter element and re used the old o rings and gasket you could have an air leak in the oil line. Some times you wont see a fuel leak, but the air will draw in at rest then when the burner starts the fuel pump has to purge the air before it can pump fuel to ignite. When the weather gets really cold and the fuel oil gets thick the burner wont light at all. Joe, also keep in mind that all gun feed type oil burners (and gas gun burners as well) are draft induced, even the old ones that used a flue or chimney. Oil gun burners have the fuel pump coupled directly to the motor/inducer fan, with a ignition transformer wired to the motor start leads, so they should light immediatly on start up. Gas guns, depending on brand, have any where from a 15 second up to a one minute purge cycle. The second blower that he descrives as an assist is an assisted draft inducer. These are installed in cases where the chimney doesnt have the proper natural draft, in some cases because of trees around the chimney, a chimney that was built too short, or in an older home, when neighboring buildings have been built that inter fere with natural air currents over the chimney top. Safety controls... An oil gun should have a 45 second lock out, no matter if its an old unit with a stack sensor, or a newer unit with primary control/photo eye sensor. If it doesnt light in 45 seconds, the safety trips, and you have to press the reset button to re start it. Never press a reset button more than once. If it trips again after the first reset call for help or you could have a explosion.
    Last edited by a moderator: Jan 6, 2007
  4. vaplumber

    vaplumber Guest

    Oh. Sorry Joe. Just re read the post. Yes, if the boiler is direct vent, the second motor he hears start could be a power vent. I apologize once again. Seems like Im doing a lot of this lately. Lol!
  5. tviapiano

    tviapiano New Member

    Messages:
    17
    Location:
    Massachusetts
    Thanks for the great info Joe and vaplumber.

    The unit does not seem to make any loud noises when there is a delayed ignition, but it does sometimes produce an odor (oil-like) that lasts a few seconds... almost like a puff of smoke, but it does not seem to be visible.

    I have never had to press the reset button, so I guess the oil is firing up before the 45 second lock-out.

    They did provide the tune-up specs - all of the specs you listed.
    Here is what he listed:

    Gross Stk Temp 450
    Net Stk Temp 400
    CO2 % 11
    Smoke Trace
    Breech draft -.04
    Overfire draft -02
    Efficiency 83%

    I was not able to watch as he did the maintenance, so I'm not sure if he used testing instruments. He did change the oil filter attached to the tank, but I don't know if he changed the o-rings or gasket. The filter screws into the bottom of the valve attached the oil tank and looks very similar to an automotive oil filter - don't know if that helps identify the type.

    And yes, there is a chimney and the second motor is a draft inducer, as indicated on the motor housing.. I just didn't know the proper term for it.
    It's a ranch style house, so maybe that explains the need for the draft inducer, since it is a relatively short chimney - just going through the basement, first floor, and attic.

    I would probably correct the flow on the coil myself - I've done a fair amount of sweating and I feel confident that I could easily fix it myself.

    I will definitely call them back to check on the intermittent delayed ignition.

    Thanks again!
  6. joe in queens

    joe in queens New Member

    Messages:
    36
    Given those stats, sounds like a pro serviced your system and was using instruments.

    The only thing I'd be slightly concerned about is the trace of smoke, slightly low CO2, and slightly high stack temps. I'd like to see smoke at ZERO and CO2 a percentage point or so higher, and the stack down a bit. If this is an older unit, that might be the best they could do. You have the make and model of the boiler and burner, or at least the approximate age of the boiler?

    Really small difference in gross and net stack temps... the ambeint air temp the boiler was operating under was only 50F?

    In any event, let us know what the tech finds... at least you're not dealing with a hack.

    VAplumber, 45-second trial for ignition times are all but gone... can really flood up a chamber on those. 15's are increasingly standard now. On Riello's they're about 3 seconds, almost impossible to flood up a chamer. And Becketts with the R7184 "3-strikes and you're out" control also prevents the dreaded overfed beast. Downright scary... seen access doors, barometric dampers, and even flue pipes go flying... makes you want to put R7184's on all of them. But I only pressed the red button once of twice... yeah right, LOL! Sorry for the little rant there...
  7. vaplumber

    vaplumber Guest

    Joe...didnt realize they had changed the lockout. I havent installed an oild furnace since back in about 2003, and at that time, the ones I installed still used the white-rogers or honey well controllers with the 45 second sensor. Yea, Ive seen lots of damage cause by homeowners trying to light off a faulty burner. Get a little vapor in there and they pop like a gas burner.
  8. tviapiano

    tviapiano New Member

    Messages:
    17
    Location:
    Massachusetts
    Thanks again for the great info Joe and vaplumber.

    That's great info: I have the service notes from the past several years, and yes the different stats look similar year to year, but it's really helpful to have a pro comment on what the stats should be.

    Is the stack temp the actual temperature of the smoke stack leading from the boiler to the chimney? How could that be lowered, adjusting the amount of oil being consumed or the amount of air being mixed in?

    Maybe the 50F was because the boiler is right next to the door to the garage - and that door and the garage door were both open the whole time he was there - so he could go to this van easily...

    It's a Weil McClain Gold Oil boiler and Beckett burner, not sure of the model numbers. I can get them tonight. I believe it is approximately 8 years old.

    The lockout is definitely 45 seconds - that is printed on the Honeywell box (forget what this is called - maybe the flame sensor control?) just to right of the ignition coil.

    I would never reset the burner more then once if it tripped. It has never tripped on me yet, and the delayed ignition issue has not gotten any worse, but does still happen occasionally. I plan on having it looked at early next week.

    Thanks again for all the help!
  9. joe in queens

    joe in queens New Member

    Messages:
    36
    You pretty much have it right... stack temp is the temperature of the flue gases going up the flue pipe to the chimney. It's measured through a small test hole in the flue pipe near the boiler. So high stack temps means your money is going right up the chimney.

    But you can't have stack temps too low either. Once you start getting 350F net and under, the flue gases will condense. With CO2 and the sulfur in fuel oil, the results are disasterious... we're taking acid rain inside your chimney, flue and boiler, which will rot out and destroy everything. It will literally eat everything from the insides out, including the chimney mortar. Chimney guys ain't cheap, either is new boiler equipment... better to have slightly higher stack temps.

    Since clearly a pro doing the work with the correct instruments, the fact that a trace of smoke being reported leads me to believe the tech probably figured on giving you the most efficiency for your fuel dollars, and trace smoke is negligible it the unit is serviced annually and won't cause any signigicant sooting or problems. My own personal preferance is zero smoke, and I'll pay a little more in fuel costs... but then again I'm lazy, my own personal boiler I don't service for years - and don't need to.

    When oil was cheaper, it was zero smoke, who cares about a few percentage points of efficiency. With more expensive oil, many dealers and service companies are doing there best to maximize efficiency, and will make this compromise. However, in such cases annual service is a must - as it is with ALL fuel burning equipment - but now it really can't be skipped.

    With your equipment, the WM Gold - which is a "pin-type" boiler - I would not want any smoke, however, since those pins are extremely difficult to clean, and usually can't be done with "conventional" methods. Given the age and type of equipment, getting zero smoke should not be an issue. Any pin-type boiler should be set to zero smoke in my opinion, because the loss of efficiency from the pins sooting and plugging is far greater than any gains with a trace of smoke. This heat exchanger design is impossible.
  10. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    I found this site because of this thread.

    About three years ago I completed my lifetime goal of designing and building my own vacation house. It’s in the mountains of North Carolina and in a “resort areaâ€, about 20 minutes from Boone. I hired a friend of mine as a general contractor since he went to school in the Boone and had some contacts in the area. We managed to get some great subcontractors but also ended up with “subs from hellâ€, most notably the plumber. He “bad mouthed†me all over town, so that may have something to do with the service problems that I have experienced, but that’s another story.

    For the heating I chose a Beckett oil fired boiler, model AFII 150. I spec’d a forced air system with an indirect domestic hot water. I placed the system in the basement garage so the waste heat from the boiler itself would keep the garage warm. I also planned for a long horizontal run on the direct vent boiler, running over a false ceiling in the “bunk house†portion of the basement, so I collect more waste heat that way, and I totally eliminated a chimney in the house. I got two bids, one “reaching for the sky†out of Boone, and he was the only local guy that could find. I ended up with a more reasonable bid out of Hickory, about 90 minutes away, and he ended up doing a great job. However, he’s too far away to be my service guy. The other guy that lost the bid isn’t interested.

    We are there nearly every weekend during the winter and the tank is in the basement next to the boiler, so I’m able to keep tabs on the fuel level easily. I had a “guaranteed delivery†contract with my first oil supplier but I called him periodically anyway to tell him what the fuel level was. One weekend in February the float indicator was down at the bottom so I sticked the tank and there were 7 gallons left. The house is located at nearly 5000’ elevation so it gets pretty cold up there. Fortunately I have a large propane tank and a gas stove so I shut the burner off and kept everything from freezing during the next two weeks while I was waiting for the supplier to grace me with his presence. It cost me about $200 or so in propane (no thermostat on that heater).

    My new supplier seems to be more dependable, but just to let y’all know what type of people we are dealing with, the driver wrote the combination to the entrance keypad in ball point on my garage door, adjacent to the keypad. He doesn’t service burners, and I’ve service my own (circa 1970’s) boiler in the past, so I figured I’d DIY.

    I bought the tube brushes and cleaned out the boiler last time I was up there but I couldn’t re-start the boiler because the primary controller locked me out. I the figured that I was in over my head with electronic doo-dads and such so after many, many phone calls I found a guy 30 minutes away in Spruce Pine. It’s been a month now and the guy never showed up and no longer returns my phone calls.

    So I’m back to DIY mode and as such found this site. So far I’ve learned that the Honeywell R7184 primary controller locks out after three tries. I then I found my manual for it, which tells me to hold the button down for 30 seconds to reset it. I’m going back up there this weekend and will go for round two and hopefully come back with a medal this time. While I’m at it I’ll replace the electrodes and nozzle.

    After I get the system running again I have some issues that maybe y’all can help me with:

    1. I am currently looking to purchase a Combustion gas analyzer, and the cheapest one I can find that measures O2 and CO is $540 at Cole-Palmer. Is there a cheaper unit available? I can justify the cost with increased efficiency because of the price of fuel but that still seems high.

    2. The burner instruction manual says to adjust the air “until a trace smoke level is achieved†then increase to reduce CO2 by 1 or 2 percentage points. I couldn’t find a smoke or soot tester, so can I measure CO instead of smoke?

    3. Bekett publishes on its web site “The effect of Elevation on Oil Burner Firingâ€. This states that an increase in the burner air setting may be required. Is this in addition to the setting in issue 2?

    4. I am also interested in installing Beckett’s “HetManagerâ€, which promises 10% reduction in fuel consumption. Any advice on this or other types of add-ons would be appreciated.
  11. Bill Arden

    Bill Arden Computer Programmer

    Messages:
    584
    Location:
    MN, USA
    1,2. Why bother. I have a tester, and there is very little difference in efficiency between where it starts to soot up and where the flame blows out.

    2. By adjusting it yourself, you have eliminated the minute changes due to Elevation.

    4. I am sure it states "up to" 10% since the savings are based on inefficient operation.

    I would worry more about keeping the electrodes, nozzle and photo sensor clean.

    I had a problem with my oil fired furnace and found that the photo sensor got dirty.

    PS: Buy a CO/Fire detector.

    PPS: I think this thread should be moved to the HVac section.
  12. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    I have a CO detector upstairs and smoke detectors all around the house (per code).
    Last edited: Jun 27, 2008
  13. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    1. Because the manual says to? Everything that I have read tells me that efficiency drops off either way from zero smoke, and the purpose of adding a little bit more air is to ensure sooting does not occur when left to run unattended- which is almost all the time. Also, how do I know I am at “zero smoke” when the vent is 15’ long and on can’t be seen from where I am when adjusting?
    2.
    3. That would be my guess.
    4. According to Beckett, “it's guaranteed to reduce heating fuel consumption by at least 10%!” http://www.becketthm.com/
  14. Southern Man

    Southern Man DIY Hillbilly

    Messages:
    530
    Location:
    North Carolina
    I'm "Bumping" this thread because I'd like some advice on adjusting the air setting on my oil burner. The installer set it at 3.5, and after three years (mostly weekend use) the return tubes on the boiler had a decent amount of soot on them. I now have it set on 4. Is it worth getting a CO tester to help set this correctly?
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