Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

Even I get head scratches at times, Tim Help please.

I have a Buderus G124x/32 153 KBTU boiler It is connected to a nice new chimney liner. The liner is 6" corrugated stainless in an 8"x8" clay tile. The chimney runs up the out side south wall of a ranch home to a total height above the boiler of 16'. I checked the gas pressure to the manual and it lines up fine on both sides of the gas valve. Numbers are escaping me at this moment though.

So to the problem. Twice since the liner was installed the blocked vent switch tripped and needed reset. On my second call there after the chimney company came back and said their liner was fine I removed the plug in the damper for standing pilot systems to keep the chimney pumping. So far knock on wood it is still running with out tripping. It never tripped even with me baby sitting it for over two hours and having it fire into a cold and warm chimney. Weather conditions were similar the days I was there and the days it tripped. Any feed back would be appreciated as Tech support never heard of this before and I do not like guessing on the solution. I know I am not the only guy to have this happen to. The chimney may be a red herring and I may be over looking the issue. So what do you think?

Thanks for the help.
Cost is what you spend , value is what you get.

cell # 413-841-6726


  • Tim McElwainTim McElwain Member Posts: 4,357
    Charlie assuming that

    the vent damper is installed above the draft hood with a standing pilot and the damper plug in place all the products of combustion from the pilot will spill out the draft hood and trip the spill switch. I think you fixed when you removed the plug as it supposed to be removed with a standing pilot and left in for spark ignition.

    Other factors to consider concerning size of the liner a Type B vent 15 feet high with 15 foot lateral run will handle 198,000 BTU's. Corrugated liners have 20% less capacity than B Vent so it would handle about 120,000 BTU's which would make the liner too small. However if there is minimal or zero lateral it will handle 285,000 BTU's and 20% of that would be 228,000 plenty of room.

    The fact of a short chimney and being located  with three sides exposed can also affect its ability to create a good draft.

    Did you do a combustion analysis? What is the draft reading on both sides of the draft hood?
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    Did a combustion test, numbers were good.

    did check for draft. The Horizontal is 8' so I figured 168 kbtu for it from the liner companies chart. I did not install the liner or the boiler. I was called in by the owner who I went to high school and grade school with. The boiler was installed by the previous owner and the liner by a chimney guy. The boiler is not standing pilot. I am concerned the damper is not working as it should but the new liner has me thinking it is simply too small.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Tim McElwainTim McElwain Member Posts: 4,357
    Charlie sometimes

    if the vent damper is directly after the draft hood it will cause premature tripping of the spill switch. The solution is to move the damper as close to the vertical vent (B Vent or chimney) This will allow for some dissipation of the flue gas temps help in the vent when the damper closes.
  • icesailoricesailor Member Posts: 7,265
    Scratching chimneys:

    Charlie, If you did your CEU last year with a PHCC of MA last year, there was a big discussion about these three sided chimneys and their problems. They just never get hot and cause all kinds of draft problems.
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    I was there a continuing ed

    The chimney is where it is and it does past mustard. I took my classes in Chicopee where do you take your Ice?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Mark EathertonMark Eatherton Member Posts: 5,843
    edited December 2010
    Cold stack slugging...

    Charlie, If you go to the CO section, there is a substantial thread that I started some time ago about your problem.

    As a possible solution, if you placed an aquastat bulb at the draft hood inlet, and if you sense a temperature of 40 degrees F, then turn on a small heater or flood light near the draft hood inlet, you will be able to maintain hot air rising, and when the boiler fires it will draw and be fine.

    Hokey, yes, but very functional. THe alternative is to keep the mechanical room warm, which will keep warm air rising up the chimney.

    You might even consider modifying the draft hood by putting a barometric on the breaching, and block the open hood. Also place a couple of spill switches around the baro's outlet. In some cases, this works like a champ, but have had cases where it didn't work.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    So far

    Taking the plug out of the damper seems to be keeping the chimney warm. The boiler is in a finished basement that is heated, So no need to install heaters.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • icesailoricesailor Member Posts: 7,265

    2009 in Bellerica. 2010 in Plymouth, MA

    How's the make up air? That can raise heck with you on these situations. I've seen some strange things with fans running.
  • icesailoricesailor Member Posts: 7,265


    You DO know your draft. Complicated trying to explain something that you have discovered through intuition and experience though,
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    fairly drafty 1970's

    tract housing. no exhaust fans except on the first floor bathroom and kitchen. Not strong enough to get rid of burnt toast smoke.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • sweetcheekssweetcheeks Member Posts: 1

    hello I have a rheem ruud furnace 2002 model and I have no lights on a new control board I have 115 volts coming in to it nothing coming out. the old one was doing the same thing so bought a new one and it isn't working tryed rerunning wire from breaker box same thing please help
  • IronmanIronman Member Posts: 5,563
    Have You Checked...

    The Transformer and the control circuit fuse?

    You've posted your question as a reply to an existing thread. You need to post it as new thread if you want more exposure and responses.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • GWGW Member Posts: 3,729
    competing appliances?

    I may ponder whether the basement is going negative; if it happens again i would pop by on a cold morning and run all the appliances and vent fans, (they don't run a wood fire right?), then start the boiler and check draft/co. 8' is a bit of a run.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • JackJack Member Posts: 1,044
    Change the vent connector

    You have a substantial horiz run. I go back to my conversation with Rich Krajewski at Brookhaven. In all of his chimney modellings he said the one thing that made the most pronounced difference in an (any)appliances draft was an insulated vent connector. How about a b-vent connector
  • Tim McElwainTim McElwain Member Posts: 4,357
    When you chart out

    the difference between single wall vents and double wall you will find that changing to a double wall both vent and vent connector will double its capacity.

    That and when you are unable to get a proper rise increase one size.
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    so far it is working

    I was thinking the B-vent to the liner but I did not want to spend their money without a definite answer. I think the liner should have been larger but nothing to back it up with beside gut feeling. The liner guy will not change to a larger size as he says the chart says it works. The budget does not allow for a new liner since they just paid for the one they have. If it goes again I will try and get the b-vent to the chimney.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • JackJack Member Posts: 1,044
    On outside chimneys,

    Even lining can sometimes not help a lot, on those initial start-ups at least the cold mass of the chimney just overpowers the natl draft. Compound that with a long horiz run and you can easily be in a jam.

    I have the same system. [email protected] Electronic ignition, 3' rise, 3' lateral, all b-vent, to exterior lined chimney and for 14 yrs it has been bullet-proof...well, once I installed their vertical pilot upgrade.
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    Found the problem today with lots of colorfull language

    omitted here so we can keep this family friendly. I get a call from home owner that they had reset the switch on the draft hood several times over night to keep the heat running. Steam was coming out from draft hood. Turns out the liner I was assured was 6" was not 6" but was 5 1/2" with a 6" adapter into the boiler room and a 6" cap outside. Liner has been removed and chimney now vents well. CO detector was blocked by a desk the children used for drawing at. when desk was pulled out detector went off. I will see about getting the right size liner installed as soon as the snow melts down a bit. With the height and run out the liner that was actually installed is rated 131 Kbtu's. the boiler is 132.5 Kbtu's. with the cold last night and the liner being almost big enough it drafted well by the time I would get to the boiler. The issue was during the cold overnight. Town inspector has been notified and will be involved with any new liner. I made the mistake of believing others when it came to the measurements.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • icesailoricesailor Member Posts: 7,265
    Scratching Liners:


    You da man.

    Perserverence always wins out in the end.

    And the liner guys just knew they were right and you were wrong.
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    Yes I was a bad guy

    as far as the liner guy was concerned. This was the first liner he had to remove in 20 years he had to remove. The home owner, her two young kids, her mother and father all think I am a pretty good guy. I am going to have to get the right size liner in there when the weather melts some of the snow. Glad its a short chimney.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Tim McElwainTim McElwain Member Posts: 4,357
    It is good to remember that

    liners size for size with "B" vent have a 20% less capacity. Ideally use the charts that come with the liners.
  • Charlie from wmassCharlie from wmass Member Posts: 4,123
    Also never believe other people

    when they tell you a size. MEASURE IT YOURSELF! I forgot that one here.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!