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Exhaust CO in Heatmaker:

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icesailor
icesailor Member Posts: 7,265
in Gas Heating
I'm changing an old Heatmaker boiler to a Vitodens 100. I've been going over how I will do this install in a crawl space with a 20 YO Amtrol Boiler Mate with a circulator and an Air Handler that is piped so that water flows through the coils whether its is calling or not. It runs on the system pump.

It also has a recalled Plex-Vent exhaust that is all separated and it only has this exhaust. The make up air comes from under the house. the crawl space. The exhaust piping seems to be well over 200 degrees. I can't touch it.

I have a personal CO detector I carry for places like this. There was no CO in the crawl space, none around the boiler. I went outside and stuck the CO detector against the exhaust termination. It went up to 131 PPM of CO. What is excessive for this LP gas exhaust? I know it is high. The owner knows it needs to be replaced and it is going to be replaced next week or so.

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  • Tim McElwain
    Tim McElwain Member Posts: 4,621
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    I like to see

    100 PPM air free CO, however with that old a unit it may be hard to get it down from 130. What was the O2, CO2 readings?



    As long as no CO is present in the dwelling place or combustion zone it should hold for a few weeks until it gets changed.



    Mark E and I were just talking bout Heatmakers with the old Plex Vent and Ultra Vent exhaust systems. They just fall through the cracks and nobody pays attention after a while.
  • icesailor
    icesailor Member Posts: 7,265
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    CO in Heatmaker:

    Tim,

    This one has been a problem for years. I don't service it. It's 20 years old. I'm replacing it. It has an interesting vent system. Because they didn't use the factory vent system, they did something else. They took a 6" SP tee and a 6X3 SP reducer and ran the 3" plex vent through it. The tee faces down and draws fresh air for combustion through the tee. There's a tee in the plex-vent and a reducer glued in with a reducer to drain condensate. I don't know how legal it is but it was inspected and approved. I have seen a lot of them vented like this. Every time I go in this crawl space to drain the water, I test it for CO. There's never been any. The gas guy who has serviced it felt that the inside pipe may be failing. I was only wondering about the 131 PPM CO I found at the exhaust outlet at the outside of the building. It's the highest I have ever registered on my personal CO detector.
  • Tim McElwain
    Tim McElwain Member Posts: 4,621
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    Yes the Heatmaker

    could use a concentric vent or a Plex Vent or Ultra Vent, with the tee you describe and it gets its air for combustion from within the space the Heatmaker occupies
  • icesailor
    icesailor Member Posts: 7,265
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    Exhaust:

    Interesting. I always cast a jaundiced eye toward that vent set up.

    In reading the Veissmann Vitodens 100 install manual, I see that they suggest hooking them up in a similar way if you are in a salt air environment. The Munchies I see that are near the water just look awful inside from the chlorides in the air. I'm going to contact Veissmann about doing this because of the chlorides in the air. 
  • Tim McElwain
    Tim McElwain Member Posts: 4,621
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    Icesailor as you research

    Mod/Cons from the first on the scene up to the present time and going back to some early negative pressure systems such as Heatmaker one of the areas that has been drastically changed is how these units are vented.



    As testing and some trial and error in the area of venting has occurred we now have a lot more flexibility in how the equipment can be vented and also how air for combustion is supplied. The key thing to remember when obtaining air for combustion from with in the space then air for combustion rules from NFPA 54/ANSI Z223.1 National Fuel Gas Code or International Fuel Gas Code come into play. I have found units installed in a closet with a solid core door getting air for combustion from within that space and it certainly is not adequate. The rules for confined space come into play 50 BTU's per cubic foot.
  • icesailor
    icesailor Member Posts: 7,265
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    Make up air

    Tim,

    IMHO, there is no such thing as too much make-up air.

    This place is a 6 block crawl space with a lot of foundation vents. Make up air isn't a problem here.

    I will have to snorkel the vent on the new Vitodens. Veissman says to not use more than 5 fittings, coming and going on the vent not counting the first two. So, I guess I will have to use the inside air for the intake. And the salt environment is a bummer. Veismann doesn't recommend taking outside combustion air in such an environment. I've seen and heard of a lot of Munchkins that looked like they spent their life outside at the beach.
  • Tim McElwain
    Tim McElwain Member Posts: 4,621
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    Just a little clarification

    on terms, "Make-Up-Air" is defined as air needed to replace air removed by mechanical exhausting. Air for combustion is air specifically dedicated to the combustion process and has several different ways it can be obtained according to NFPA 54 and International Code.
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