Originally Posted By: dspencer
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Must not enforce it much…only see it on once here…Monday Im calling the City HVAC code office.
Must not enforce it much…only see it on once here…Monday Im calling the City HVAC code office.
Originally Posted By: dandersen
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J., don’t they use makeup/combustion air vents when the HVAC equipment is installed in condition spaces?
Originally Posted By: jwilliams4
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Not necessarily. If the furnace has sealed combustion it is installed
with it's own make-up air. In both cases I mentioned the water heater
was electric and there was no real need for make-up air. The fireplace
was also a manufactured type that had it's own m/u air. But the AHJ
said if it's on the books, it's in the house.
And that's O.K. by me.
--
"not just an inspection, but an education"
Originally Posted By: dandersen
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I agree, the AHJ gets what he wants.
The new high efficiency furnaces are the way to go, but I was asking about non-high efficient furnaces in existence or installed. I guess they didn't consider or just didn't use fresh air makeup to break the negative pressure?
Do you not see this at all, or was it something just done different?
I can see bringing fresh air through the return to break the negative pressure in the house because you condition the air as its brought in, versus using fresh air makeup which brings very cold air and from outside.
That six-inch duct seems a bit much to me for residential applications.
Do you have any information on this design criteria?
Uncontrolled, or unbalanced this would seem to pressurize the structure excessively. My experience with this application is commercial only. You have minimum fresh air settings (set by the state) and variable control through the economizer.
Originally Posted By: jwilliams4
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In Hamilton county 6" is normal–actual furnace flue area plus 30%.
Things may have change some since I retired from HVAC a few years
age. I did like the idea of bring the air to the return, as you suggested,
but most AHJ didn't quite understand and wouldn't allow it.
Only in this one township (Ohio has townships, counties, and anything
else they can find as a tax base) have I seen this--high-efficiency furnace
with make-up air. This county is one of the fastest growing in the USandA
but sometimes...well I won't say nuthin'--"they" may be watching.
--
"not just an inspection, but an education"
Originally Posted By: dandersen
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Yup I hear you!My wife is from Hamilton County.
Thanks for the info!
Originally Posted By: jwilliams4
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Actually, it’s not Hamilton County I’m talking about (it’s shrinking)
There are two nearby counties that are growing like crazy. One of them
is referred to in the previous post.
--
"not just an inspection, but an education"