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Ignition problem

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guzzinerd
guzzinerd Member Posts: 435
edited 1:49AM in Radiant Heating

My neighbor's old gravity feed gas boiler has been running fine as long as I've known her.

A couple weeks ago the pilot went out. It would light and the boiler fire up again but go out after a minute or two (both pilot and main flames).

She has the thermocouple replaced, no improvement. Then she had the gas valve replaced with the same model (robertshaw). It worked for about 5 hours and then went out again. I dont think it's the thermostat because the pilot goes out as well.

She's had the same company (local plumbing) go out twice, each time with 2 different guys. After billing her 5 hours they can't figure it out.

Ideas? Thanks

1000031622.jpg 1000030821.jpg

Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

Comments

  • bjohnhy
    bjohnhy Member Posts: 199

    This is natural gas supply? Was the gas valve set up for NG or propane? Did they check the gas pressure at boiler ? Static pressure? dynamic pressure? I don't see a sediment trap in that piping? I wonder if the line is obstructed?

  • mattmia2
    mattmia2 Member Posts: 16,601

    what is the line pressure when it goes out? sounds like it might be a bad service regulator or something like that.

  • 4GenPlumber
    4GenPlumber Member Posts: 140

    That is beautiful. More info please. I assume the pic is the old gas valve, pic of the new?

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,128

    Boiler on a wood floor?

  • mattmia2
    mattmia2 Member Posts: 16,601

    is that piece of sheet metal in front of the combustion chamber supposed to be there?

    bjohnhy
  • 109A_5
    109A_5 Member Posts: 3,934

    Restricted (contaminated) pilot orifice. Not enough pilot flame.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • mattmia2
    mattmia2 Member Posts: 16,601
    https://forum.heatinghelp.com/discussion/comment/1891694#Comment_1891694

    if the pilot burner was clogged it would go out when it wasn't firing too.

  • guzzinerd
    guzzinerd Member Posts: 435
    https://forum.heatinghelp.com/discussion/comment/1891690#Comment_1891690

    Been in that spot over 100 years, imagine that.

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • guzzinerd
    guzzinerd Member Posts: 435
    https://forum.heatinghelp.com/discussion/comment/1891694#Comment_1891694

    I'll check it. Thanks

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • guzzinerd
    guzzinerd Member Posts: 435
    edited 3:25AM
    https://forum.heatinghelp.com/discussion/comment/1891693#Comment_1891693

    The combustion chamber is actually above that, behind the area with the central metal circle. Has always been there. Tomorrow I'll try lighting it after removing that sheet.

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • guzzinerd
    guzzinerd Member Posts: 435
    https://forum.heatinghelp.com/discussion/comment/1891686#Comment_1891686

    Natural. I'm assuming the techs she called knew that. Will have to find someone who can take those readings

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • pedmec
    pedmec Member Posts: 1,309

    Did you check the millivolts on the thermocouple with the pilot lit? did they change the pilot assembly? sounds like the pilot flame might just be barely making contact due to dirty pilot assembly.

  • 109A_5
    109A_5 Member Posts: 3,934
    https://forum.heatinghelp.com/discussion/comment/1891699#Comment_1891699

    Restricted / marginal, not totally clogged. Water in the gas main.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    bjohnhy
  • guzzinerd
    guzzinerd Member Posts: 435
    https://forum.heatinghelp.com/discussion/comment/1891706#Comment_1891706

    I haven't. Initially I asked her to call licensed professionals since I'm not one. At this point I'll start the list in this thread the best I can.

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • mattmia2
    mattmia2 Member Posts: 16,601

    let's clarify this, does the pilot stay lit with the main burner off?

  • guzzinerd
    guzzinerd Member Posts: 435
    edited 4:35AM
    https://forum.heatinghelp.com/discussion/comment/1891709#Comment_1891709

    It does not. When I light the pilot, the main burner turns on. While burning, the pilot goes out followed by the burner. About 2-3 minutes altogether

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • 109A_5
    109A_5 Member Posts: 3,934

    My guess is you never tied this scenario @mattmia2 is referring to.

    Light the pilot. Do not let the main burner come on. Does the pilot stay on indefinitely ?

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    mattmia2
  • guzzinerd
    guzzinerd Member Posts: 435
    https://forum.heatinghelp.com/discussion/comment/1891719#Comment_1891719

    I have not. Let's say it stays on. What does that say? Low gas pressure?

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • mattmia2
    mattmia2 Member Posts: 16,601

    gas supply or combustion air or maybe venting/draft

  • 109A_5
    109A_5 Member Posts: 3,934

    Yes low gas pressure, or maybe a more realistic scenario, the pressure drops significantly at the boiler due to a supply restriction. That's why testing not guessing usually works best.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,934

    I'd be curious about the inlet pressure during all modes of operation and when off.

    image.png image.png

    https://www.pscia.com/ASSETS/DOCUMENTS/ITEMS/EN/1-489.pdf

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,934

    So 4 guys, 5 hours, a thermocouple and a gas valve and no pressure testing ? That seems a bit pitiful to me. Parts cannon troubleshooting fails again.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • guzzinerd
    guzzinerd Member Posts: 435
    https://forum.heatinghelp.com/discussion/comment/1891728#Comment_1891728

    Yep. Same company that maintained the boiler in my apt building before I bought the place (It was a disaster). I give thanks for this forum everyday.

    Heading over to light her pilot soon. Will report back.

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • guzzinerd
    guzzinerd Member Posts: 435

    Here are pics showing the new gas valve and pilot, which I've just lit, thermostat off. Will see if it stays lit until tomorrow

    1000031637.jpg 1000031638.jpg 1000031639.jpg

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • guzzinerd
    guzzinerd Member Posts: 435
    https://forum.heatinghelp.com/discussion/comment/1891724#Comment_1891724

    At less than $150 they were, relatively, cheap parts. I would have done the same. Now she has spares :).

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • mattmia2
    mattmia2 Member Posts: 16,601

    that combination valve alone is around $300-$500.

    unless the draft from the main burner is moving the pilot burner the issue isn't the pilot burner being dirty.

    those doors being the way they were when whoever replaced the valve adjusted the combustion is important to the combustion. They affect how much primary and secondary air the burner gets.

  • guzzinerd
    guzzinerd Member Posts: 435
    1000031642.jpg

    Bryant 245-8, 430k btu, 2-pipe steam in a 1930s 6-unit 1-story apt building in the NM mountains. 26 radiators 3800sqf

  • bjohnhy
    bjohnhy Member Posts: 199

    Glad to see the gas piping was fixed and sediment trap added in. Although having a flex gas pipe exposed in middle of kitchen/pantry is not exactly safe. HOpe you are able to figure this out.

    guzzinerd

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