QOD for 04/15/04 (HVAC)

Originally Posted By: gbeaumont
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Hi to all,


sorry for the delay this morning

regards

Gerry


--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
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Originally Posted By: gbeaumont
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, to those who got it wrong, I also thought it was 200F until I research the answer icon_confused.gif icon_confused.gif


I guess no-one knows it all,

Regards

Gerry


--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
gbeaumont@inspectiondepot.com

"Education is a journey, not a destination"

Originally Posted By: Blaine Wiley
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Well, I failed because of my study guide, a York Tech-sheet, and other various sources.


From the HVAC section of Real Estate Home Inspection:

"On most furnaces, the limit control is calibrated to shut off the burner if discharged air temperature reaches or exceeds 200 degrees F".

I guess this is just one more instance of why there is such disparity in home inspectors interpretation of how it should be....Now, how is that outlet supposed to be wired again ![nachi_sarcasm.gif](upload://6HQh6KbNiD73gqTNQInjrR2zeJw.gif)


Originally Posted By: gbeaumont
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Hi Blaine


you know I will take another look at that as I thought it was 200 F as well but the sourses I looked at said 150F, lets hear the debate (with links if possible) and we'll thrash it out.

Regards

Gerry


--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
gbeaumont@inspectiondepot.com

"Education is a journey, not a destination"

Originally Posted By: kmcmahon
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bwiley wrote:


"On most furnaces, the limit control is calibrated to shut off the burner if discharged air temperature reaches or exceeds 200 degrees F".


That's what I learned(between 180 and 200) and voted!!


--
Wisconsin Home Inspection, ABC Home Inspection LLC

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Originally Posted By: dedwards
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Gerry,


My source says the high limit to be 250 in most states (code requirements) My source is the textbook we used when I went thru HVAC school a couple of years ago. The figure 150 sounds way too low for an “upper” limit setting. It gets 150 degrees almost immediately. I am on the way out the door to go to work but as soon as I can I will scan the text and illustration out of the book and if I can “break the code” for scanning and sending it I will post it here. It’s a brand new scanner w/ software and I am still on the learning curve on how to use it.


Originally Posted By: gbeaumont
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no knowing something (especially if it’s the answer to one of my own questions) icon_redface.gif


here is the "code" version of reality, but I'd still like to hear the real world stories.

IRC says dependent on manufacturers specifications.

UMC (uniform mechanical code) automatic air outlet temp, limit to <250F required (UMC 306.0)

regards

Gerry


--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
gbeaumont@inspectiondepot.com

"Education is a journey, not a destination"

Originally Posted By: kmcmahon
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So with the exception of #4 I guess they are all correct!



Wisconsin Home Inspection, ABC Home Inspection LLC


Search the directory for a Wisconsin Home Inspector

Originally Posted By: gbeaumont
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hi to all,


Kevin, no I think #1 would have to be wrong, think about it if the temp limit was set that low then the furnace would be short cycling like crazy and never produce enough heat to raise the temp to the room thermostat presets. Unless of course some one knows different ![icon_confused.gif](upload://qv5zppiN69qCk2Y6JzaFYhrff8S.gif)

Regards

Gerry


--
Gerry Beaumont
NACHI Education Committee
e-mail : education@nachi.org
NACHI phone 484-429-5466

Inspection Depot Education
gbeaumont@inspectiondepot.com

"Education is a journey, not a destination"

Originally Posted By: kmcmahon
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Very true…but according to the code you quoted, it would be ok! icon_lol.gif


I guess code and common sense come into play quite often!



Wisconsin Home Inspection, ABC Home Inspection LLC


Search the directory for a Wisconsin Home Inspector

Originally Posted By: jmyers
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Gerry,


Would the high limit hold true for a gas fired boiler? Just mentioning that because that is what the high limit was set at on the home I sold.

I voted for 200 but that was a pure guess, since I have never taken the burner controls apart on one and looked! ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)

Joe Myers


Originally Posted By: dvalley
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This can be raised as high as 210 degrees F., if needed in severe weather.


For heating systems with coils to heat domestic hot water, high limit setting of 210 degrees F. with low limit setting of 190 degrees F. and differential setting of 15 is recommended for optimum amount of domestic hot water.


--
David Valley
MAB Member

Massachusetts Certified Home Inspections
http://www.masscertified.com

"Some cause happiness wherever they go; others, whenever they go."