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Rotted Flue Pipe

While diagnosing a pilot light issue, I discovered a gas fired HWH heater flue pipe substantially rotted.




Probably been this way for awhile. Aggravating as plumbers and gas company have been on prem multiple times recently for system inspections etc. Anyway ...

Plumber has been called back to deal with this and fully inspect the other flues.

The HW heater is approximately 50 years old (copper tank that my plumber begs me to leave in-place). The flue is probably the same age.

My question. Is this flue pipe rot normal age related wear and tear, or is there something else going on (condensate etc.).

Cheers





Comments

  • pecmsg
    pecmsg Member Posts: 3,532
    You really need a combustion analysis performed to know what's going on!

    Im guessing Mr. Plumber has never done one or knows how.

    Look at the National Comfort Institutes site for a qualified contractor.
    https://www.myhomecomfort.org/find-a-contractor/
    SuperTech
  • Jamie Hall
    Jamie Hall Member Posts: 20,417
    If it's really that old, it's a wonder it's in as good shape as it is. Flue gas does condense, even though one might think it was hot enough not to, and is incredibly corrosive.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • pecmsg
    pecmsg Member Posts: 3,532
    edited October 2022

    If it's really that old, it's a wonder it's in as good shape as it is. Flue gas does condense, even though one might think it was hot enough not to, and is incredibly corrosive.

    How can that be inspected yearly, even every other year and not be found?

    Only incompetence!
    MikeAmannSuperTechJcheat22
  • woobagooba
    woobagooba Member Posts: 168
    Yeah I am pretty peeved that this went unnoticed by multiple people. We have a new plumber on board and will start will full maintenance/combustion test of all the gas appliances. And flue inspections!

    Will also fully inspect the house's smoke/CO alarms. Pretty sure there is a brand new smoke/CO detector within feet of this flue, wondering why it never alarmed.
  • pecmsg
    pecmsg Member Posts: 3,532

    Yeah I am pretty peeved that this went unnoticed by multiple people. We have a new plumber on board and will start will full maintenance/combustion test of all the gas appliances. And flue inspections!

    Will also fully inspect the house's smoke/CO alarms. Pretty sure there is a brand new smoke/CO detector within feet of this flue, wondering why it never alarmed.

    UL listed CO detectors alarm when the Co level exceeds 70PPM for up to 3 hours.

    Make you feel really safe doesn't it.


    I recommend at least 2 Defender Low Level CO detectors. They alert at 9 PPM

    SuperTech
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,782
    Hi, Going with double wall vent pipe can keep the inner pipe hotter, thus reducing condensation and improving draft. Might be worth looking into. B)

    Yours, Larry
  • mattmia2
    mattmia2 Member Posts: 7,147
    edited October 2022
    That might have been drawing well enough that despite being perforated most of the products of combustion were going up the vent.

    And keep the copper water heater.
    EdTheHeaterManSuperTechJcheat22
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,097
    The pipe looks awful. If the pipe is 5 years old I would be condensation concerned. If it's 50 years old I wouldn't be concerned (except that the pipe needs replacement)
  • JakeCK
    JakeCK Member Posts: 1,128
    edited October 2022
    I want to see the rest of the hot water heater.
    mattmia2SuperTech
  • woobagooba
    woobagooba Member Posts: 168
    edited October 2022
    Thanks for the tips re: the Low Level CO detectors.

    Here are some pics of the entire situation. Three non-condensing boilers (2 old Teledyne and 1 newer Burnham) and two HW heaters (one circa 1977? and the other newer). All gas fired. All using combustion air from the basement. Older house, not tight. Three apartments, two of them share a water heater.

    Most of the appliance's flues are showing signs of flue pipe corrosion and the older Teledynes are showing signs of internal corrosion. Water drips from the draft hood of the Burnham when it is firing,

    The fully corroded HW heater flue pipe was replaced so no more flue gas venting into the basement.

    Diagnosis ... there is something wrong with the chimney which is casing condensate to flow back into the appliances. Next step ... chimney expert is coming in a few days to fully inspect the chimney.









  • JakeCK
    JakeCK Member Posts: 1,128
    edited October 2022
    Wow.

    Is this a private residence or an apartment? That's a lot of equipment for just one house.
    MikeAmann
  • JakeCK
    JakeCK Member Posts: 1,128
    Also that is one old dehumidifier. :S
  • mattmia2
    mattmia2 Member Posts: 7,147
    That water heater is from the 50's or maybe 60's.

    With that dripping and multiple appliances you need to find someone that understands combustion and draft well to look at the whole system. It might mean replacing the draft hoods with draft regulators or changing some vent sizes.
    Larry Weingarten
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,782
    Hi @woobagooba , Following up on what @mattmia2 said, see if you can find an ANS or ANSI sticker on the tank, that will put you withing three years of the date of manufacture.

    Yours, Larry
  • captainco
    captainco Member Posts: 735
    For some unexplainable reason, this equipment hasn't severely poisoned anyone yet. Yet!! Need someone with a combustion analyzer and a draft gauge to diagnose the venting problem. You can see the rust on the floor from the boiler which is a sign of poor venting.
    STEVEusaPASuperTech
  • Bob Harper
    Bob Harper Member Posts: 955
    You're telling me a plumber and the gas co. were in here "inspecting" and no one said anything? That's gross negligence. If someone got sick or died, people could go to jail. I don't care if you're there to light a pilot or look for leaks. If a pro or agency is in there and fails to call out not just the first rotted pipe but all of it, someone should go to jail. That's criminal. People rely on our knowledge and skill. If you don't know or accept these vent connectors are gross blaring signs of a bigger problem, neglect and end of service life, you're in the wrong business. By the time corrosion manifests on the exterior, the interior is well corroded. That means the inner lining has lost its corrosion resistance as required by code. It has begun losing its sheetmetal gauge thickness, which is dictated by code. Corrosion will cause failure of the gore in adjustable elbows, which is a source of CO poisonings when the pipe separates. The pipe must be supported. You cannot rely on the physical connections and gravity to support pipe.

    If you have a condensate problem, fix the equipment. You also need an intact, compliant venting system. If the equipment or venting are failing, defective, damaged, corroded, disconnecting, worn out, crumbling or otherwise unsuitable for the intended application, by code, it must be repaired or replaced.

    If the contractor failed to adequately warn the owner about the problem and consequences, they can easily be lit up in court should something go wrong. It's not acceptable practice anymore justifying leaving corroded, worn-out components in place with the hope and assumption it will last just a little longer. No. Replace it if it does not meet the standard.

    If you test a standing pilot control and it does not drop out within the specified time, do you leave the equipment in service? Say anything to the owner? Do you even test for flame proving function? You should be because that a MAJOR reason why customers call us--they just want to know it is 'safe' to operate. Now, the word 'safe' is a dirty word because its unachievable. It's an absolute under any and all conditions. We can make things saf-er using codes, standards, listed products, comprehensive testing and continued training and certifications.
    Jcheat22
  • woobagooba
    woobagooba Member Posts: 168
    edited October 2022
    The two flues were inspected today by disconnecting the appliances and examining the flues from the basement. Both flues are drafting but the draft is weak. Flues look to be in good shape from what was able to be observed from the basement. It was noted that this basement has 6 direct fire gas appliances and probably not enough make up air. Its been in this configuration for a very long time.

    Plan is to leave one of the windows cracked to see if that resolves the observable condensate drip from one of the boilers. If that works then a damper to the exterior will be installed. Gets complicated after that ... flue liners, etc.
  • JakeCK
    JakeCK Member Posts: 1,128
    I still don't think it's ever been mentioned why there is so much equipment down there. What purpose does this building serve?
    PC7060
  • woobagooba
    woobagooba Member Posts: 168
    edited October 2022
    3 units ... three boilers. 2 direct HW heaters, one of which is shared by two of the units. Been in this general configuration for nearly 70 years (with at least one cycle of appliance replacements).
  • pedmec
    pedmec Member Posts: 712
    Did you measure the humidity level in the basement? Judging by the pics you don't have much of a floor left so i'll bet you have tons of moisture coming thru thru floor and into the basement. Soil acts like a sponge. Moisture on the surface of the soil will evaporate and by capillary attraction will be replaced by moisture below it. Never ending cycle. And it gets worse with age. Remaining concrete floor just keep disintegrating letting the situation get worse and worse as the years go by.

    How well is the grading from the house. Does it pitch away from the house? Are your down spouts connected and draining away from the house? Does the ground puddle?

    If your flues look like this what does the chimney look like?

    Been this configuration for 70 years? Ill bet that 70 years ago those Teledyne Laars boilers didn't exist. That the efficiency of the boiler it replaced was much less resulting in a cooler chimney. Just saying its not the same.

    I'll bet you have around 300,000 btus in the basement or close to it. You need, by Massachusetts code 15,000 feet of cubic space to meet the minimum requirement for combustion air. We use nfpa 54 so it ain't going to be much different around the country. i would start upgrading your systems while you still can. With legislation to electrify everything going on around the country all the rebates for gas are going to be crushed. Not to mention the most important thing SAFETY FIRST
  • woobagooba
    woobagooba Member Posts: 168
    Basement floor is in decent shape. I estimate the basement is on the humid side. Brick foundation and concrete floor. I think you are close on the total BTUs down there and we are short on the code required square footage.
  • JakeCK
    JakeCK Member Posts: 1,128
    edited October 2022
    These all look like hot water boilers. 

    If it were me I would do a heat loss on the whole building and see if there was a way to go down to one boiler for all three units using zone valves or circulators.

    That newer unit, is it oversized? A lot of boilers are oversized by a factor of two. And a duplex or triplex has a much lower heat loss per unit because of shared walls compared to separate buildings.

    Would have to change how they pay for heat.


  • WMno57
    WMno57 Member Posts: 663
    Ask you Insurance agent if your landlord insurance will be cheaper if you go all electric.
  • JakeCK
    JakeCK Member Posts: 1,128
    WMno57 said:
    Ask you Insurance agent if your landlord insurance will be cheaper if you go all electric.
    If I was an insurance company I wouldn't insure that at all until it was all rectified. That's a tragedy waiting to happen.
  • WMno57
    WMno57 Member Posts: 663
    @jakeck Ins agents and companies are happy to insure anything. They will also use any excuse to weasel out of paying. They also have no qualms about dropping you at any time for no reason.
    MikeAmann
  • JakeCK
    JakeCK Member Posts: 1,128
    WMno57 said:
    @jakeck Ins agents and companies are happy to insure anything. They will also use any excuse to weasel out of paying. They also have no qualms about dropping you at any time for no reason.

    Maybe it varies from local to local but out this way my ins co took issue with there being no railing on my second floor flat roof "porch" and made me put up at least a railing behind the door leading out there. Yes that was dangerous but at least most people can see that danger and appreciate it. CO pouring into a house from a back drafting boiler? Not so much.
  • WMno57
    WMno57 Member Posts: 663
    My Insurance company had a problem with my 1959 Square D QO panel because it was "old". Best panel ever made, then and now.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,913
    edited October 2022
    @JakeCK ... Are you the Jake from State Farm? ...What are you wearing?
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
    WMno57MikeAmann
  • JakeCK
    JakeCK Member Posts: 1,128
    @JakeCK ... Are you the Jake from State Farm? ...What are you wearing?
    Nothing o.o