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Near death carbon monoxide experience (ME)

Mitch_6
Mitch_6 Member Posts: 549
is a Jim Davis type repair over the oem draft hood?

Did you try a star cap?

Does the boiler start on low fire then ramp up or just light?

Once you have established draft how is the combustion Analise?

Mitch S.

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Comments

  • Scary orphan...

    I want to first stress that the product that will be seen in the following set of photographs is NOT the problem. Got it? It could have been an atmospheric boiler of ANY manufacturer and the problems STILL would have been prevelant. Got it? Good.

    We inherited this job from a less than scrupulous first time snowmelt hydronics wannabe plumbng contractor who shall remain nameless. He installed a tekmar snowmelt sensor, but didn't have enough wire to make it all the way back to the mechanical room, so he lied to the GC and told him someone must have cut the sensor wires underground. The GC gave him plenty of opportunity to fix it, at the GC's expense, and the installer kept no showing, so we inherited another orphan.

    Understand that when we first got there, the system had never fired automatically, so basically it was never commisioned properly, until we inherited it.

    We replaced the sensor with a sensor with a lead long enough to get all the way back to the mechanical room, hooked it up and fired the system and checked it for proper operation. Everything was peachy keen, but it was also like 90 degrees F outside.

    6 months later, we get the call from the customer, "No snow melt on the back auto court..." We show up, it's dead cold in the boiler room, find the auto ignition system locked out. Reset it and watched as the room filled with products of combustion from the relief hood on the appliance. It could not establish a draft against the cold slug of air sitting in the three story stack. Hence, the blocked vent relief hood, gas barometric damper and associated spill switch at the baro damper. Worked like a champ when we tested it after modification.

    Now, every time it snows, we get the same call, "No snow melt on the back auto court..." We show up and go through the paces, finding the same results we always have found but can not replicate upon arrival. This recent major storm hits, and I anticipate the call, calling the homeowner and she confirms a cold boiler room. I show up, confirm ignition lockout, reset and watch as the boilers burners all back flash and start burning inside the burner tubes. Have you ever smelled this before? It was also spilling out the bottom of the boiler and through any minute leaks around the hood block we'd nstalled. I could actually smell it as soon as I walked into the house, and it was REALLY strong at the top of the stairs leading down to the basement boiler room. Mind you, the rest of the home is forced air. THis boiler room sits all by itself, with plenty of combustion air, and no heat unless the boiler is running. Dead cold.

    I watched in horror as the burners belched black carbon into the mechancial room, thereby filling the combustion chamber with CO2 to the point that the pilot snuffed, and the burner ignition control locked out (no retry if loss of pilot during sustained call, CSD1 compliant). I immediately reset the boiler, and there was just enough upward draft now going up the stack to allow the burners to light properly, on the top of the OUTSIDE of the burners, establish draft and pull all the byproducts of combustion out of the room and up the stack.

    AHA, I'd finally caught it doing something I'd never been able to catch it doing before.

    Now what... THe only time the boiler ever gets a call to fire is when it is sitting ICE COLD. With little to no residual heat in the mechancial room to maintain draft.

    I have my idea as to what to do next, but I wanted to use this as an educational tool, allowing each of you to express your ideas before I disclose mine.

    Post haste, I found that a CO detector, in the room next to the boiler room was showing a peak CO reading of 53 PPM.

    When I queried the HO, she said that her eyes had been burning, and that she felt achy and had a horrendous head ache. Said she felt like she was hung over without reason.

    I told her I though she'd been exposed to a low level dose of CO poisoning, and suggested she air the house out and get some fresh air herself. I had no CO readings within the mechanical room when I checked it during diagnosis, and quite frankly, forgot to test when the black death started belching back out of the combustion chamber. I was more interested in getting the problem fixed than I was seeing how many PPM of CO I had invited into the room. Probably a bad decision on my part, but you have to go with your gut in these situations and time lost is critical. I suffered no long or short term issues, that I'm aware of.

    So, fellow life savers, what would YOU do?

    BTW, for those people reading this that have never installed a snowmelt system before, it is approximatley 90 linear feet from the back of the house, where the mechanicals are located, to the front of the house, where the actual snowmelt system is located. The installers chewed up 180 feet of tube just getting from where they were to where they NEEDED to be.

    Obvioulsy, they didn't do this on a regular basis...

    ME
  • S Ebels
    S Ebels Member Posts: 2,322
    Veeeedy intedestink

    First thought that popped into me head is to install a power venter ala Tjernlund or the like. Second thought is to yank the atmospheric boiler and install a high efficiency unit which of course would be draft induced. Who the heck installs standard efficiency boilers for a low temp application which can be minimum 20% more efficient when run with a condenser?

    Edit: I'm fully awake now as compared to last night's post and after looking at the pics again this is what I'm wondering. I have no experience with Laars product as far as how they are supposed to be setup up but I'm curious as to whether the barometric is the factory approved method for draft regulation. Most atmospheric boilers that I've seen have an integral draft hood or else it's incorporated into the the flue right off the top of the boiler. I'd want to check out the manual for that boiler and see what the recommendations are for that type of installation. I'd also shut the thing off until some resolution of the problem is made. (I'm assuming you've done that already) We don't need any more CO headlines.

    And a PS: Is that thing sitting on carpet?

    PSS: Gotta love that great looking tubing job!
  • The Boiler Dr.
    The Boiler Dr. Member Posts: 163
    I concurr .... but

    What temperature is this boiler seeing @ startup? Is there any mixing devices to prevent ice cold solution from entering the boiler? A power ventor "might" overcome the cold chimney but cold water in the heat exchanger will still kill the flue temperature and lift. What condition is the exchanger in?

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  • Mark Hunt
    Mark Hunt Member Posts: 4,909
    Mark

    Is that a "make-up" air pipe I see behind the boiler?

    If it is, you need to draw an arrow on it so the air knows which way to go. Same goes for the flue pipe. s/o

    If possible, mechanically pressurize the room on a call for the boiler to fire. Break the burner circuit through a proving switch.

    As Steve said, power vent the boiler.(I'd still mechanically pressurize the boiler room)

    Or..........put in a sealed combustion, condensing boiler.

    Mark H

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  • brucewo1b
    brucewo1b Member Posts: 638
    A Fields CAS system would be nice in this case

    But I will bet that a call on of Circs first will get enough heat in the boiler to get flow going in the right direction before burners come on.
  • Paul B._2
    Paul B._2 Member Posts: 62
    Posting from Home because this is important

    Mark.

    I would strongly urge you to return to the project and Red Tag that boiler until Laars can get a representative out to the site. If TM sales in Denver is open on Tuesday, I will have someone contact you. If they are not open, I will make it my first priority on Wednesday morning when Laars is open.

    The modifications you have had to make are Never necessary with that model. We have hundreds of Mighty Therms installed on cold start snow melt systems, and draft at start up is not an issue.

    It's difficult to see in the photo's, but the wire-way on the front of the boiler looks as if heat may have distorted it, and that usually indicates reflected heat in the combustion chamber from heat exchanger fouling. If the burners have been operating with a fouled heat exchanger, the reflective heat can actually cause them to warp. Once that happens, the boiler will never light, and burn properly again.

    Our mounted pump is intended for primary/secondary applications, and is good for a distance of up to 15' out and back from the primary loop. Inlet temperatures below 110° require a low temp bypass assembly to prevent condensation on start up. It should be close enough to the heater that I should see it in the photo's, and I don't.

    I never encourage the use of single wall pipe with that model either, type B vent from our integral draft diverter, to the termination on the roof is desirable.

    In summary, I would like to further discuss this project with you, and see what we can do to help correct this installation.

    Very Sincerely,

    Paul Bock

    Applications Engineer, Laars Heating Systems.
  • hvacfreak
    hvacfreak Member Posts: 439
    support

    I just had to say that I am impressed beyond words by your post above ( PaulB ). Proactive ( spelling) , making phone calls , making things happen ...this is the support we need from manufacturers of all the products we use. I understand that life safety was the topic , but I feel you would have responded the same way for any tech. question or problem .

    Is Teledyne -Laars the same company ( I hope this is not a " moron " question ). I used to install the small oil-fired ( Riello) boilers ...many in old " farm houses " with stone chimneys ( stainless flue liners ) . I keep in touch with 2 that are over 10 yrs old and are doing great. -Mike
  • Gas man_7
    Gas man_7 Member Posts: 8
    Burning back !

    I never liked installing a 90 elbow directly off any appliance ! Is it possible that the main house's system could create negative pressure , along with an ice cold stack 30'feet high , create 0 ? draft ! What about installing a live pilot ? I' ve got to go get my morning coffee and wake up ! Will keep an Eye on this one ! To all a merry christmas ! Dan , for all that you do ! thanks !
  • hr
    hr Member Posts: 6,106
    A belt clip CO detector

    is another tool that is well worth it's money for all installers and service contractors.

    Mine has alerted a number of times as I work alone in mechanical rooms. Think of your own safety as well as the owners :)

    hot rod

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  • Pinball
    Pinball Member Posts: 249
    Warm the room

    How about installing a small loop of baseboard in the mech. room? It would do three things. (1) keep the boiler warm for better start up. (2) keep the room warmer than outside temps for better draft. and (3) give the snowmelt a "running start" on a call for melting. The little Extra fuel to warm just the mech room probably would be negligable in the scheme of things. Especially since they're heating the outdoors anyway.(given the nature of "snowmelt"

    Al (pinball) Bruno
  • First replies...

    Steve, great diagnosis. I considered a Tjernlund, however mounting compliance is an issue, plus generated noise and vibration (office directly above mech rm,) and it's just one more thing to go wrong. I won't comment on your last suggestion until the very last. I did however tell the HO that if her GC had hired us, we WOULDN'T be having this conversation... The use of a baro damper is not in their installation manual, but under certain extreme circumstances I have had the factory engineers sign off on the retrofit application. A spill switch is MANDATORY. As for shutting the thing off, I moved a CO detector into the boiler room and told her it if goes off to call my cell and leave the house. This is a 25,000 square foot home. The indoor/outdoor carpet is cut around it.

    Boiler Guy, The boiler is seeing whatever temperature the fluid is on the snowmelt panel. Wednesday, it was coming back below freezing. There is a tekmar 664 with variable speed injection, and a minimum return water temperature setting of 140 degrees F. VSI transfer loop is approximately 30 feet long, 1" copper with a Taco 007 doing the transfer duties. And it is functional. The exchanger is brand new. Remember, due to the fact that the controls were never completed, the boiler had never fired.

    Al, that thought did cross my mind, and money is obviously not an issue here. I'm pretty sure she doesn't even see the utility bills. They go to someone else who pays them. Remember, the house is heated with forced error. THe GC doesn't believe in doing hydronic heat because he wants to provide AC as a part of his package...Hence the reason I don't typically work for him unless there is a snowmelt system required. That said, I bid his last snowmelt job and he told me my number was twice that of the next "competitor", so I got fired... We still work on this job for the HO, not the GC any more. I should note that there is a duct serving this room from the forced error furnace in an adjoining room, and the damper is open. Thermostat is in the other room. Moving the thermostat into this room would cause significant overheating in the other adjoining room.

    Mr. Hunt, yes that is one of 2 12 " combustion air vents serving this room. It is in complaince with the UMC requirements. I considered the arrow thing, but I couldn't figure out how to draw inside the pipe... Again, I considered mechanical pressurization and timed draft induction, but just another thing to go wrong. I'll think about your last suggestion...

    Bruce, See my response to Ebels and Hunt regadring mechanical pressurization. there is a 2 HP in line pump serving the distribution system that had been running for 2 hours before I got there to witness the back flash, so that idea obviously is field tested and failed. Every time we've been back there, all the pumps (except the VSI) were running, to no avail.

    Paul, I consulted Rick Meek on the situation during the height of the storm. He made some suggestions to me to get the unit to lite off slowly and avoid flash back (restrictive orifice in the primary gas valve vent line). He also ran me though the check list of other things to check (manifold pressures, supply pressures etc) which I had already checked prior to calling him. It is not often that I have to call them because I have been working on their equipment (Laars) for around 20 years now, but it is nice to know that they are there when you need them. You have a good firm repping your product in TM Sales. As I previously posted, I got the unit to fire and draft correctly and placed a hard wired CO detector in the room with the appliance. I understand what you are sayng about not having to field modify, but this is not the first atmospherically vented appliance that we have had to perform ths feat on. Not something I WANT to do, but in most cases, it works much better than the factory supplied relief hood. We maintain -.02" W.C. pressure in the flue breaching right at the flue connection. The burner is not seeing reflected energy. The heat exchanger looks like brand new. As previously explained, other than initial start up, the HXer is NOT seeing condensate production issues. THe burners also look like new as well. No warping or distortion, and trust me, I've seen some SERIOUSLY warped and distorted burners from a lack of service...and mis-applied appliances.

    The boiler primary is less than 20 feet in length, full size.

    Once the boiler fires, it gets above dew point in less than 5 minutes. The tekmar control doesn't start transferring energy until the return water is above 140 degrees F. The operator is set for 160 degrees and the manual hi limit is set for 200 degrees F. The boiler is set up ideally to avoid long term condensation production, and nothing else could have been done to allay those fears/conditions in my professional opinion.

    I honestly do not feel that the use of B vent for the 8 or 7 feet between the single wall connector and the B vent riser would really make any difference. The warm air never made it that far to begin with before we had to block the spillage coming from the relief vent. It used to fill the room with CO2 and snuff the flame before it caught draft. Self limiting CO production if you will... Good thing someone didn't replace the ignition controller with a control that would continue to try and restart or something more serious could have happened long ago... Maybe a need to label critical control as such in LARGE RED LETTERS???

    Paul, as other posters have said, I appreciate your involvement, and I encourage all manufacturers to follow your lead. Things happen in the field that can't possibly be replicated in the laboratory. I know because I see them ALL the time, and when I tell the manufacturer what I'm seeing, they all say the same thing, "Gee, that's never happened to us before..." Not that your company has said this, but I have heard it way too many times. As I stated at the very first of this post, this problem has NOTHING to do with the manufactuer of the appliance. It could have happened to ANY appliance manufacturer in an atmospheric drafted condition, and it HAS happened with other appliance manufacturers, and I corrected them the same way. Eliminate the fixed draft relief hood and apply a barometric damer and roll out switch, problem typically goes away. This is the first snowmelt boiler I've had to apply this to, and it obviously wasn't able to overcome the slug of cold air before the burner snuffed itself out and locked out. Rick has all my telephone numbers if you feel the need to further contact me on Tuesday. I will however, be busy trying to re-assemble my fleet of vehicles which are spread out all over the state.

    Mitch S, yes I am Davis certified. Can't use a star cap due to large copper gondola serving vent penetrations on roof (code compliant). Yes, starts low, then jumps to high, then rolls back to low as fluid approaches control set point (2 stage gas train, lo-hi-lo). Once draft is established, numbers are perfect.

    HR, that tool is the next tool on the list of MUST HAVE tools, and will be on this years tools purchased list. Got any suggestions of manufacturers? And I thought about my own personal safety, for about 3 seconds. You now me...

    Steve, condensing boiler, SEALED COMBUSTION...

    Plumdog, trust me, when we inherit an orphan, we own it and we treat it like it was our own. This boilers has been gone over with an ULTRA fine tooth comb. All the adjustable parameters are perfect. Only time I've seen flash back at the burner face is with LP or low manifold pressures and lazy gas.

    Gas Man, We performed combustion air zone test and saw ZERO pressure differential between the boiler room and adjoining room with all exhaust fans in the home running. It is not a negative air pressure condition. It is a cold slug of air, 3 stories tall condition. Kind of like push starting a coal train.

    Realolman, that is a maual reset spill switch. If the damper stuck open, that is theoretically where the flue products would spill. It is wired in series with the TT circuit of the boiler. It is a normally closed switch, that opens on rise and requires a manual reset. It has NEVER tripped since we installed it.

    The orange dot in the middle of the sheet metal modification is where we test for draft and flue gas analysis. That is a plug of high temp silicone sealant.

    EDIT: I would not suggest to ANYONE that they make these kind of field modifications without having first attend the NCI courses that Jim Davis teaches. You are biting off a rather large chunk of liability that you could choke on if improperly applied.

    In the interest of getting more responses and interaction, I am not going to tell you what my solution is until later this afternoon. Very interesting ideas coming down the pike here, and a few obvious ones that will benefit not only this manufacturer, but others as well. (Cleaned up post coffee:-))

    ME
  • realolman
    realolman Member Posts: 513


    What is the little green thing with the wire on the barometric draft?
    It looks like some sort of proximity sensor.
    What would that be for? It looks as if it would only read when there is lotsa draft.

    What does it read?
  • Plumdog_2
    Plumdog_2 Member Posts: 873
    Tall Cold Flue

    is gonna be a problem. Like others have mentioned, Power Vent or Fan-in-a-can would improve matters. But I would check that the unit is not over-fired (sea level set-up) and that the heat exchanger has not become plugged with either soot or residue from condensate (unlikely if the thing hasn't been used much). Firing back in the burner tubes is what I see when they are not altitude-corrected.
  • S Ebels
    S Ebels Member Posts: 2,322
    Which one

    The condensing boiler or the "edit"?
  • tim smith
    tim smith Member Posts: 2,738
    CO production from boiler.

    > I want to first stress that the product that will

    > be seen in the following set of photographs is

    > NOT the problem. Got it? It could have been an

    > atmospheric boiler of ANY manufacturer and the

    > problems STILL would have been prevelant. Got it?

    > Good.

    >

    > We inherited this job from a less than

    > scrupulous first time snowmelt hydronics wannabe

    > plumbng contractor who shall remain nameless. He

    > installed a tekmar snowmelt sensor, but didn't

    > have enough wire to make it all the way back to

    > the mechanical room, so he lied to the GC and

    > told him someone must have cut the sensor wires

    > underground. The GC gave him plenty of

    > opportunity to fix it, at the GC's expense, and

    > the installer kept no showing, so we inherited

    > another orphan.

    >

    > Understand that when we first

    > got there, the system had never fired

    > automatically, so basically it was never

    > commisioned properly, until we inherited

    > it.

    >

    > We replaced the sensor with a sensor with

    > a lead long enough to get all the way back to the

    > mechanical room, hooked it up and fired the

    > system and checked it for proper operation.

    > Everything was peachy keen, but it was also like

    > 90 degrees F outside.

    >

    > 6 months later, we get

    > the call from the customer, "No snow melt on the

    > back auto court..." We show up, it's dead cold in

    > the boiler room, find the auto ignition system

    > locked out. Reset it and watched as the room

    > filled with products of combustion from the

    > relief hood on the appliance. It could not

    > establish a draft against the cold slug of air

    > sitting in the three story stack. Hence, the

    > blocked vent relief hood, gas barometric damper

    > and associated spill switch at the baro damper.

    > Worked like a champ when we tested it after

    > modification.

    >

    > Now, every time it snows, we get

    > the same call, "No snow melt on the back auto

    > court..." We show up and go through the paces,

    > finding the same results we always have found but

    > can not replicate upon arrival. This recent major

    > storm hits, and I anticipate the call, calling

    > the homeowner and she confirms a cold boiler

    > room. I show up, confirm ignition lockout, reset

    > and watch as the boilers burners all back flash

    > and start burning inside the burner tubes. Have

    > you ever smelled this before? It was also

    > spilling out the bottom of the boiler and through

    > any minute leaks around the hood block we'd

    > nstalled. I could actually smell it as soon as I

    > walked into the house, and it was REALLY strong

    > at the top of the stairs leading down to the

    > basement boiler room. Mind you, the rest of the

    > home is forced air. THis boiler room sits all by

    > itself, with plenty of combustion air, and no

    > heat unless the boiler is running. Dead

    > cold.

    >

    > I watched in horror as the burners

    > belched black carbon into the mechancial room,

    > thereby filling the combustion chamber with CO2

    > to the point that the pilot snuffed, and the

    > burner ignition control locked out (no retry if

    > loss of pilot during sustained call, CSD1

    > compliant). I immediately reset the boiler, and

    > there was just enough upward draft now going up

    > the stack to allow the burners to light properly,

    > on the top of the OUTSIDE of the burners,

    > establish draft and pull all the byproducts of

    > combustion out of the room and up the

    > stack.

    >

    > AHA, I'd finally caught it doing

    > something I'd never been able to catch it doing

    > before.

    >

    > Now what... THe only time the boiler

    > ever gets a call to fire is when it is sitting

    > ICE COLD. With little to no residual heat in the

    > mechancial room to maintain draft.

    >

    > I have my

    > idea as to what to do next, but I wanted to use

    > this as an educational tool, allowing each of you

    > to express your ideas before I disclose

    > mine.

    >

    > Post haste, I found that a CO detector,

    > in the room next to the boiler room was showing a

    > peak CO reading of 53 PPM.

    >

    > When I queried the

    > HO, she said that her eyes had been burning, and

    > that she felt achy and had a horrendous head

    > ache. Said she felt like she was hung over

    > without reason.

    >

    > I told her I though she'd been

    > exposed to a low level dose of CO poisoning, and

    > suggested she air the house out and get some

    > fresh air herself. I had no CO readings within

    > the mechanical room when I checked it during

    > diagnosis, and quite frankly, forgot to test when

    > the black death started belching back out of the

    > combustion chamber. I was more interested in

    > getting the problem fixed than I was seeing how

    > many PPM of CO I had invited into the room.

    > Probably a bad decision on my part, but you have

    > to go with your gut in these situations and time

    > lost is critical. I suffered no long or short

    > term issues, that I'm aware of.

    >

    > So, fellow

    > life savers, what would YOU do?

    >

    > BTW, for those

    > people reading this that have never installed a

    > snowmelt system before, it is approximatley 90

    > linear feet from the back of the house, where the

    > mechanicals are located, to the front of the

    > house, where the actual snowmelt system is

    > located. The installers chewed up 180 feet of

    > tube just getting from where they were to where

    > they NEEDED to be.

    >

    > Obvioulsy, they didn't do

    > this on a regular basis...

    >

    > ME



    If I am not mistaken, I think the burners on that boiler are tube in a tube style. These burners accumulate dust inside which you cannot clean by brushing the outside and you cannot see the fouling directly. I wonder if construction dust has fouled them. Pull them out and wash them out. Shake out water and reinstall. Just a thought. I have had several boilers that started to burn back in venturi during contstruction because they run them against my recommendation. Tim
  • tim smith
    tim smith Member Posts: 2,738
    CO production from boiler.

    If I am not mistaken, I think the burners on that boiler are tube in a tube style. These burners accumulate dust inside which you cannot clean by brushing the outside and you cannot see the fouling directly. I wonder if construction dust has fouled them. Pull them out and wash them out. Shake out water and reinstall. Just a thought. I have had several boilers that started to burn back in venturi during contstruction because they run them against my recommendation. Tim
  • Steve Gates_2
    Steve Gates_2 Member Posts: 7


    Why is the draft hood blocked off? Does the snow melt work once fired up?
  • Initial spillage...

    was coming out of the draft hood, filling the room with non combustibles (Co2, CO) and snuffing the flame because it could not catch and establish a draft, thereby locking out on ignition failure.

    Sent you a WarmBoard job the other day Steve, hope it works out for you.

    ME

  • Larry (from OSHA)
    Larry (from OSHA) Member Posts: 716
    CO belt clip monitor

    Very interesting thread.

    This is the CO monitor that we use for our personal safety and it has been VERY helpful for me and the unaware people that I visit.

    The AIM 450 CO monitor is about $400.00 or so and for my money (alright, my states/employer's money) is very worth it. We calibrate monthly and rarely need to make any adjustments. Factory set to start beeping at 35ppm.

    There are others out there that may do what you want and be less costly.

    If anyone wants any other info or further perspective, let me know.

    Larry
  • David Woycio
    David Woycio Member Posts: 107
    How's your back?

    > I want to first stress that the product that will

    > be seen in the following set of photographs is

    > NOT the problem. Got it? It could have been an

    > atmospheric boiler of ANY manufacturer and the

    > problems STILL would have been prevelant. Got it?

    > Good.

    >

    > We inherited this job from a less than

    > scrupulous first time snowmelt hydronics wannabe

    > plumbng contractor who shall remain nameless. He

    > installed a tekmar snowmelt sensor, but didn't

    > have enough wire to make it all the way back to

    > the mechanical room, so he lied to the GC and

    > told him someone must have cut the sensor wires

    > underground. The GC gave him plenty of

    > opportunity to fix it, at the GC's expense, and

    > the installer kept no showing, so we inherited

    > another orphan.

    >

    > Understand that when we first

    > got there, the system had never fired

    > automatically, so basically it was never

    > commisioned properly, until we inherited

    > it.

    >

    > We replaced the sensor with a sensor with

    > a lead long enough to get all the way back to the

    > mechanical room, hooked it up and fired the

    > system and checked it for proper operation.

    > Everything was peachy keen, but it was also like

    > 90 degrees F outside.

    >

    > 6 months later, we get

    > the call from the customer, "No snow melt on the

    > back auto court..." We show up, it's dead cold in

    > the boiler room, find the auto ignition system

    > locked out. Reset it and watched as the room

    > filled with products of combustion from the

    > relief hood on the appliance. It could not

    > establish a draft against the cold slug of air

    > sitting in the three story stack. Hence, the

    > blocked vent relief hood, gas barometric damper

    > and associated spill switch at the baro damper.

    > Worked like a champ when we tested it after

    > modification.

    >

    > Now, every time it snows, we get

    > the same call, "No snow melt on the back auto

    > court..." We show up and go through the paces,

    > finding the same results we always have found but

    > can not replicate upon arrival. This recent major

    > storm hits, and I anticipate the call, calling

    > the homeowner and she confirms a cold boiler

    > room. I show up, confirm ignition lockout, reset

    > and watch as the boilers burners all back flash

    > and start burning inside the burner tubes. Have

    > you ever smelled this before? It was also

    > spilling out the bottom of the boiler and through

    > any minute leaks around the hood block we'd

    > nstalled. I could actually smell it as soon as I

    > walked into the house, and it was REALLY strong

    > at the top of the stairs leading down to the

    > basement boiler room. Mind you, the rest of the

    > home is forced air. THis boiler room sits all by

    > itself, with plenty of combustion air, and no

    > heat unless the boiler is running. Dead

    > cold.

    >

    > I watched in horror as the burners

    > belched black carbon into the mechancial room,

    > thereby filling the combustion chamber with CO2

    > to the point that the pilot snuffed, and the

    > burner ignition control locked out (no retry if

    > loss of pilot during sustained call, CSD1

    > compliant). I immediately reset the boiler, and

    > there was just enough upward draft now going up

    > the stack to allow the burners to light properly,

    > on the top of the OUTSIDE of the burners,

    > establish draft and pull all the byproducts of

    > combustion out of the room and up the

    > stack.

    >

    > AHA, I'd finally caught it doing

    > something I'd never been able to catch it doing

    > before.

    >

    > Now what... THe only time the boiler

    > ever gets a call to fire is when it is sitting

    > ICE COLD. With little to no residual heat in the

    > mechancial room to maintain draft.

    >

    > I have my

    > idea as to what to do next, but I wanted to use

    > this as an educational tool, allowing each of you

    > to express your ideas before I disclose

    > mine.

    >

    > Post haste, I found that a CO detector,

    > in the room next to the boiler room was showing a

    > peak CO reading of 53 PPM.

    >

    > When I queried the

    > HO, she said that her eyes had been burning, and

    > that she felt achy and had a horrendous head

    > ache. Said she felt like she was hung over

    > without reason.

    >

    > I told her I though she'd been

    > exposed to a low level dose of CO poisoning, and

    > suggested she air the house out and get some

    > fresh air herself. I had no CO readings within

    > the mechanical room when I checked it during

    > diagnosis, and quite frankly, forgot to test when

    > the black death started belching back out of the

    > combustion chamber. I was more interested in

    > getting the problem fixed than I was seeing how

    > many PPM of CO I had invited into the room.

    > Probably a bad decision on my part, but you have

    > to go with your gut in these situations and time

    > lost is critical. I suffered no long or short

    > term issues, that I'm aware of.

    >

    > So, fellow

    > life savers, what would YOU do?

    >

    > BTW, for those

    > people reading this that have never installed a

    > snowmelt system before, it is approximatley 90

    > linear feet from the back of the house, where the

    > mechanicals are located, to the front of the

    > house, where the actual snowmelt system is

    > located. The installers chewed up 180 feet of

    > tube just getting from where they were to where

    > they NEEDED to be.

    >

    > Obvioulsy, they didn't do

    > this on a regular basis...

    >

    > ME



  • David Woycio
    David Woycio Member Posts: 107
    How's your back?

    Shoveled enough snow yet? My hot tub will be getting lots of use next couple of days. We always separate with an external HX on snow melts. Didn't see one on your pics. Protects boiler from too cold returns and all the nasty's associated with and makes service EZ. Commercial usually constant recirc on the slab side with WWSD.

    BTW what is your fav. snow melt control(s)? Been useing WR set point control senor with timer w/manual over-ride

    Need to start taking canaries with you like the miners use to.

    Merry Ho Ho!
  • jp_2
    jp_2 Member Posts: 1,935
    minor point,

    mark, CO is combustable. 2 CO's + 02 = 2 CO2's.

    added info MSDS:

    http://physchem.ox.ac.uk/MSDS/CA/carbon_monoxide.html

    General

    Synonyms:
    Molecular formula: CO
    CAS No: 630-08-0
    EC No: 211-128-3

    Physical data

    A
    Explosion limits: 12.5 - 74 vol% in air

    Autoignition temperature 620 C

    ((auto ignition Nat Gas 480-620 C))

    Stability

    Stable. May react violently with oxidants; readily forms an explosive mixture with air. Extremely flammable. Note the wide explosion limits.

    Toxicology

    Toxic by inhalation. Odourless and colourless, so no indication exists of its presence in a room. May impair fertility or cause harm to the unborn child. Delayed adverse effects possible. Typical LTEL 50 ppm, typical STEL 300 ppm.

    LTEL long term explosure limit
    STEL short term explosure limit
  • Murph'_5
    Murph'_5 Member Posts: 349
    real fast

    can you put a pilot on that unit??


    Murph'
  • The Fix....

    Numerous of you hit the nail squarely on the head.

    SEALED COMBUSTION MODULATING CONDENSING boiler.

    Funny thing about this whole story. The GC who built this home saw us doing a monster snowmelt down the street from this project, and stopped by and said "So THAT'S how it's supposed to be done..." I said "This is how WE do it, but not everyone..."

    He was referring to our remote manifold boxes with the tubing emminating from there and going to the actual melted areas. 95% tube utilization versus his obviously lesser percentage. I gave him a card, and he did call us in to do his next snowmelt system located right next door to the one we were doing at that time. It has worked flawlessly since installed. Ironicly, the job he met us on never got a heat source set. It was a spec home being done by one of our favorite GC's, and he wanted to make it "snowmelt ready", but didn't want to set the heat source until the house sold. Well, the guy who bought the house didn't want to spend the money necessary to complete the system, and spent about 2 times that amount on a couple of ATV's with plows on the front for pushing snow.

    I'm betting he wishes he'd have gone with the whole system after last weeks storm. Maybe he'll call next week :-)

    But I digress. Mark Hunts suggestion of keeping the room pressurized causes me a little concern. If I do have ANY spillage for whatever reason, I am more likely to spread that contamination through out the home. No? I guess it could get blown out the combustion air/ventilation air or stack, but still, pressurizing this or any mechanical room causes me concern.

    Numerous people suggested a draft inducer, ala Tjernlund XL series. That would require additional control logic, and safety interlocks to insure safe and proper operation. More things to go wrong and keep the system off line.

    I thought of putting a sensor well on the boiler, and when ever the OSA drops below freezing, allowing the boiler to be kept in a hot (70 degrees F) condition to maintain a subtle upward flow of air, but that seems like SUCH a waste of energy, just for the sake of being able to keep this less efficient piece of equipment on line. This lady could burn money (and she is anyway) to keep the driveways free of snow, but she does have kids, and a heart and a consciencious, and wants to do the right thing for the environment, while keeping her drive way free of snow.

    As I explained to her, had her GC hired us to do the job in the first place, we wouldn't have used an atmospheric appliance. We would have used a modulating condensing boiler with a sealed combustion property, that WHEN PROPERLY APPLIED would virtually eliminate the possibility of CO poisoning. She didn't even ask how much. She said how soon can you get it in? I volunteered the approximate price to her, and told her I'd get back to her as soon as I could.

    She said "Just do it as soon as you can and send me the bill.."

    Now, you're probably asking yourselves what I plan to do with the new T/L boiler that will be coming out? It will join the other CFT boilers that we keep on hand for emergency boilers, and for temporary heat sources for apartment house conversion projects.

    Recycled boilers if you will...

    Thanks to everyone for their input and feel free to continue the discussion and ask questions.

    Thanks for learning and thanks for spreading the word about CO.

    BTW, I did three telephone interviews Thursday. Two TV stations and one radio station. Spread the word. CO poisonings CAN be prevented.

    ME
  • My back is KILLING me...

    Can I come over and hop into your hot tub, huh, can I , purty please:-)

    I've only begun to shovel... Went by the shop, and it is REALLY snowed in. Nice thing about having our trucks all over the state is that none of them are in the yard. Should make snow removal a LOT easier...

    IF we are doing snowmelt as a side affect from space heating, we do set a FP HXer, but if it is doing ONLY snowmelt, no HXer.

    My fav control is still the tekmar. I just wish and hope they figure out a way to keep their sensors from getting water logged...

    As for canaries, Tom won't allow it. He hates any animal that makes noise or has to be cleaned up after :-)

    My grand mother used to raise canaries for the Washington Coal mine.

    Merry Christmas Dave, and drop by the Breckenridge Brewing Company on Kalamath on Thursday, January 11th around 6:00 PM for a cold one and some hydronic comeraderie.

    ME
  • Hi ya Murph...

    It has a pilot on it already, although not a standing pilot. I think the code authorities might frown on me putting a standing pilot in on a CSD 1 gas train ;-)

    Nice to see ya.

    ME
  • Thanks Larry.

    I'll look into it right after we get all our trucks dug out.

    ME
  • Tim...

    The boiler is like new, rarely fires and was installed after the building was rocked. I hear you about construction contamination though...

    We prefer to use a strong vacuum over water and suck backwards on the burners.

    ME
  • Point..

    taken.

    Funny we don't hear of more explosion where CO is an issue. The source of ignition is obviously present.

    In your estimation, would not the presence of CO2 result in fouled (incomplete, partial) igniton of the gasses and even more production of CO ?

    Kind of reminds me of a local radio station. They have a game they play called "Would you rather..." with all kinds of bizarre scenarios. Would you rather die of carbon monoxide poisoning, or a violent CO explosion...

    Neither thank you...

    ME

  • David Woycio
    David Woycio Member Posts: 107
    Canaries

    Would that be Washington, PA? Lots of relatives in Canonsburg, PA. I'm from New Kensington. Grandfather worked in mines. Died of black lung but made it to 74 which ain't bad for those times. No one ever heard of OSHA in those days.

    May take you up on that beer!

    Best wishes for the new year!
  • jp_2
    jp_2 Member Posts: 1,935
    CO explosions

    if i'm reading my post right, it would take 12% CO, or 1,200PPM. EDIT: oops, thats 120,000ppm.

    i believe i have witnessed this with a wood stove being shut down too far. woodstove belch!
  • Mark Hunt
    Mark Hunt Member Posts: 4,909
    Positive pressure


    WRT atmospheric pressure in the mechanical area would make spillage impossible. All products of combustion would be forced up the chimney since the room would be pressurized before the burners light.

    A condensing boiler makes better sense in this application anyway.

    Merry Christmas Mark!

    Mark H



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