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Gas fireplace pilot assembly

lbeachmike
lbeachmike Member Posts: 175
edited February 2021 in THE MAIN WALL
Given this forum addresses "heating" I'm wondering if anybody is equipped to weigh in on the condition of the pilot assembly of my gas fireplace. Seems these are effectively the same parts found inside boilers and such. Thanks!




Comments

  • HomerJSmith
    HomerJSmith Member Posts: 2,393
    What do you want to know? It's a thermopile that's suppose to put out 750 mv. With what appears to be a piezo ignition.
  • lbeachmike
    lbeachmike Member Posts: 175
    Does the condition of everything look good? I had seen some info suggesting to clean the thermocouple and thermopile annually.
  • unclejohn
    unclejohn Member Posts: 1,833
    Cant tell but it looks to be missing pilot burner or oriface. Also there seems to be some soot on the nut that should hold the thermopile in place. Looking straight down in the second pic it looks like threads where the pot is lime some thing should be there. 
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,578
    edited February 2021
    That pilot assembly is different from a standard gas boiler or central heating furnace. That looks to be on a non vented fireplace. (meaning the flue is either blocked off intentionally or there is no flue at all) That particular pilot assembly is part of the safety system for non-vented appliances that require an oxygen depletion sensor (ODS) of some type. If the oxygen in the room where the appliance is located falls below 18% (normal near 21%) the flame must cut out. The orifice is finely machined to produce a pilot flame that barely touches the thermocouple. that thermocouple is installed at an exact dimension so the flame hits the tip at just the right place to produce a safe operating condition. As oxygen is reduced in the room as a result of insufficient ventilation the pilot flame gets smaller. That smaller flame can not maintain enough electrical energy to keep the gas valve open. The flame is then extinguished because the gas valve closed.

    Normal operation will cause lint and dust to accumulate in the pilot burner. This small blockage of air to the pilot flame will simulate the smaller pilot flame or a pilot flame that burns past the burner usually associated with low oxygen. By blowing the dust away with a drinking straw or piece of 1/4" or 3/8" tubing, right at the pilot burner outlet, you will remove the dust and the pilot will operate properly.



    Here is a video that explains how the ODS works
    https://www.youtube.com/watch?v=ImgoQR8ssQE

    another on proper maintenance of ventless (non-vented) fireplaces and other similar appliances. I recommend a professional for doing maintenance on any gas, propane, or appliances with a flame.

    https://www.youtube.com/watch?v=_hi2YozgL9o

    Yours truly,
    Mr.Ed



    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    lbeachmike
  • mattmia2
    mattmia2 Member Posts: 9,452
    That does not seem safe...
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,578
    edited February 2021
    unclejohn said:

    Can't tell but it looks to be missing pilot burner or oriface. Also there seems to be some soot on the nut that should hold the thermopile in place. Looking straight down in the second pic it looks like threads where the pot is lime something should be there

    Disagree with John,

    Looking straight down on the second picture is the pilot burner and the brass dot in the center is the precision drilled orifice. All looks fine from what I can see. It looks really clean and you should not be having any problems. Are there any issues? If so, what are they?

    If not, then I assume you are just trying to stay up to date with maintenance before there is a problem. I believe the videos posted above will help

    Respectfully Submitted,
    Mr.Ed
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • lbeachmike
    lbeachmike Member Posts: 175
    Thanks for the *amazing* amount of useful information - I can't express enough how much I appreciate this!

    Mr Ed - You really went about 5000 miles over and above here - so a very big thank you!

    Indeed this is a vent-free fireplace. However, we have the flue open so that it also is able to vent - thus there should never be any issue of oxygen depletion.

    Previously there was some orange at the tip of the pilot flame. I blew out the oxygen inlet hole and it cleared that up. Flame is now blue.

    I do not see any dust in the pilot. When I blew out the oxygen inlet, it did seem that a lot of dust or soot blew out through the pilot. It all appears to be clear.

    All of the flame ports for the unit ignite within 15 seconds of turning it on, though not all at once. The manufacturer said this is normal.

    The only thing in question is that when I turn it off and the flames extinguish, it makes a "poof" sound. I'm not sure if this is normal expected behavior.

    I would gladly have maintenance done by a pro, but I literally cannot find anybody. I previously had a "pro" do the maintenance on the other one of these that I had, and he didn't catch the most obvious of problems - damaged logs - which led to a soot problem on the face of the fireplace and an expensive repainting job. I subsequently figured out that issue myself .

    The reason I was doing maintenance / cleaning on it is because it was installed about seven years ago, used once and not used since then.