[Greenbuilding] Fresh air to boiler questions

Norbert Senf norbert.senf at gmail.com
Thu Jan 15 09:57:01 CST 2015


On Thu, Jan 15, 2015 at 9:41 AM, Benjamin Pratt <benjamin.g.pratt at gmail.com>
wrote:

> Norbert.
> There is no damper of any kind. I could add one, but there isn't much room
> beofre the brick chimney. Perhaps on the horizontal portion, if that is
> acceptable.
>

Just to clarify terminology:

butterfly damper:
an adjustable pivoting plate inside the connector pipe, designed to reduce
flow: there should not be one on an oil or gas furnace or water heater, so
it sounds like you are good to go.

barometric damper:
A Tee connection in your connector pipe, with a counterbalanced pivoting
plate that lets room air into the chimney. Designed to regulate draft, ie.,
avoid excess draft to the appliance by diluting the flow into the chimney.
Can cause CO and combustion product spillage into the basement during
startup, if chimney is cold.


> However, I am still considering a new boiler. Does anyone have any input
> as to my original question--what would be the ROI on a newer more efficient
> direct vent boiler? I just found this link, but have no way to determine if
> it is accurate.
>
> http://www.houseneeds.com/learning-center/hydronic-boilers-learning/boilers-heat-source-costs-example
> Thanks!
> Ben
>
>
>
>
> b e n j a m i n p r a t t
>
> professor art+design
> the university of wisconsin stout
>
> On Thu, Jan 15, 2015 at 7:40 AM, Norbert Senf <norbert.senf at gmail.com>
> wrote:
>
>> On Wed, Jan 14, 2015 at 4:36 PM, Benjamin Pratt <
>> benjamin.g.pratt at gmail.com> wrote:
>>
>>> Norbert, I would love to close off that 6" hole. I was told that the
>>> boiler would operate less efficiently if I do that. I suppose that assumes
>>> less oxygen
>>>
>>
>> not true, common fallacy. In some jurisdictions, building code may
>> require it, or it may be in "manufacturers installation instructions", so
>> you need to check that.
>> Only exception I can think of is a separate, sealed, furnace room. Always
>> make sure you have a CO detector, since low level CO spillage is very
>> common with your type of setup, outside air or not.
>>
>>
>>> IF that is not true, I and am ready to plug up that hole! Any ideas
>>> about the open flue of the boiler and the water heater? Are they less
>>> concerning?
>>>
>>
>> Not sure, since my experience is with wood and not oil or gas. In a
>> basement, you are very likely to have negative pressure, so on standby
>> perhaps there is not a lot of flow from the basement into the barometric
>> damper, particularly if you have an outside chimney. If you take a sheet of
>> old style newsprint, it has a grain orientation to it, and in one direction
>> you can tear it into parallel strips. This makes a handy flow visualization
>> tool, for example low flows into open fireplaces. It might be interesting
>> to check around your barometric dampers, air inlets, window drafts, etc. A
>> stick of incense, or a cigarette, is good also ;-)
>>
>>
>>> Thanks!
>>> Ben
>>>
>>>
>>>
>>>
>>>
>>> b e n j a m i n p r a t t
>>>
>>> professor art+design
>>> the university of wisconsin stout
>>>
>>> On Wed, Jan 14, 2015 at 3:04 PM, Norbert Senf <norbert.senf at gmail.com>
>>> wrote:
>>>
>>>> The air consumption of an 80,000 BTU/hr boiler is in the range of 25
>>>> cfm while it is operating. Heating that combustion air by 50 degrees F
>>>> requires about 3,000 BTU/hr, which happens no matter whether the outside
>>>> air has a direct or indirect path to the burner.  Having a 6" dia permanent
>>>> leak in the basement is a really inefficient way to do it. There is no good
>>>> engineering reason to have that leak, unless your basement is hermetically
>>>> airtight and 25 cfm would depressurize it enough to cause the boiler or
>>>> water heater or (worst case) an open fireplace to backdraft. This is
>>>> generally considered to be -5 Pa. Much more likely that a 250 cfm kitchen
>>>> exhaust hood would do it, assuming that your basement is not sealed from
>>>> the rest of the house. Clother dryers and bathroom fans also, are in the
>>>> 100 cfm range.
>>>>
>>>> On Tue, Jan 13, 2015 at 7:43 PM, Benjamin Pratt <
>>>> benjamin.g.pratt at gmail.com> wrote:
>>>>
>>>>> I have been sealing up and insulating the unfinished portion of my
>>>>> basement, but am concerned it is a waste of time and money: There is a 6"
>>>>> fresh air duct to provide proper combustion for the boiler. Also, there is
>>>>> no damper on the water heater or boiler. Therefore, a lot of cold air is
>>>>> continually dumped into the basement, and a lot of hot air escapes up the
>>>>> chimney.
>>>>>    I suppose the solution to this would be to install a new boiler,
>>>>> and to install a direct vent kit on the water heater. The boiler is around
>>>>> 15 years old, and is 84 percent efficient. If I buy a more efficient
>>>>> boiler, that is direct vented, any guess as to how much energy I will save?
>>>>> I suppose its more then just the amount of natural gas I will save with a
>>>>> more efficient boiler, since I would also be eliminating a huge source of
>>>>> air infiltration. I would like to be able to calculate the ROI, so my wife
>>>>> agrees to the purchase.
>>>>> I'd appreciate any help you can provide.
>>>>> Thanks,
>>>>> Ben
>>>>>
>>>>>
>>>>>
>>>>> b e n j a m i n p r a t t
>>>>>
>>>>> professor art+design
>>>>> the university of wisconsin stout
>>>>>
>>>>> On Tue, Jan 13, 2015 at 3:46 PM, Sacie Lambertson <
>>>>> sacie.lambertson at gmail.com> wrote:
>>>>>
>>>>>> I'm looking for an architect in Seattle who understands energy
>>>>>> efficient good building and does contemporary design work.  Welcome
>>>>>> suggestions.   Best to send these off the forum, to me directly. Sacie
>>>>>>
>>>>>> _______________________________________________
>>>>>> Greenbuilding mailing list
>>>>>> to Send a Message to the list, use the email address
>>>>>> Greenbuilding at bioenergylists.org
>>>>>>
>>>>>> to UNSUBSCRIBE or Change your List Settings use the web page
>>>>>>
>>>>>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Greenbuilding mailing list
>>>>> to Send a Message to the list, use the email address
>>>>> Greenbuilding at bioenergylists.org
>>>>>
>>>>> to UNSUBSCRIBE or Change your List Settings use the web page
>>>>>
>>>>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Norbert Senf
>>>> Masonry Stove Builders
>>>> 25 Brouse Road, RR 5
>>>> Shawville Québec J0X 2Y0
>>>> 819.647.5092
>>>> www.heatkit.com
>>>>
>>>> _______________________________________________
>>>> Greenbuilding mailing list
>>>> to Send a Message to the list, use the email address
>>>> Greenbuilding at bioenergylists.org
>>>>
>>>> to UNSUBSCRIBE or Change your List Settings use the web page
>>>>
>>>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>>>>
>>>
>>>
>>> _______________________________________________
>>> Greenbuilding mailing list
>>> to Send a Message to the list, use the email address
>>> Greenbuilding at bioenergylists.org
>>>
>>> to UNSUBSCRIBE or Change your List Settings use the web page
>>>
>>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>>>
>>
>>
>>
>> --
>> Norbert Senf
>> Masonry Stove Builders
>> 25 Brouse Road, RR 5
>> Shawville Québec J0X 2Y0
>> 819.647.5092
>> www.heatkit.com
>>
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>>
>> to UNSUBSCRIBE or Change your List Settings use the web page
>>
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>>
>
>
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
>
> to UNSUBSCRIBE or Change your List Settings use the web page
>
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>



-- 
Norbert Senf
Masonry Stove Builders
25 Brouse Road, RR 5
Shawville Québec J0X 2Y0
819.647.5092
www.heatkit.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20150115/f8bc9b02/attachment.html>


More information about the Greenbuilding mailing list