QOD for 8/26/04 (HVAC)

Originally Posted By: dbush
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Sorry to the guys in New England, Florida and Arizona.


Okay, not really, I just feel like being cruel today ![icon_twisted.gif](upload://xjO326gspdTNE5QS3UTl0a0Rtvy.gif) ![icon_twisted.gif](upload://xjO326gspdTNE5QS3UTl0a0Rtvy.gif)


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Dave Bush
MAB Member

"LIFE'S TOUGH, WEAR A HELMET"

Originally Posted By: Blaine Wiley
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We had this question before and it created much argument and consternation.


Originally Posted By: jpope
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bwiley wrote:
consternation.


I ain't afraid of no question! ![icon_cool.gif](upload://oPnLkqdJc33Dyf2uA3TQwRkfhwd.gif)

You sure you didn't mean condensation


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Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738

Originally Posted By: Blaine Wiley
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I suppose if I wanted to jump into legaleeze mode I could have said “pain and suffering” icon_lol.gif icon_lol.gif


Originally Posted By: kmcmahon
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or constipation? icon_wink.gif



Wisconsin Home Inspection, ABC Home Inspection LLC


Search the directory for a Wisconsin Home Inspector

Originally Posted By: dbush
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Blaine, we may have had this question before, but the answer is still A.


![icon_lol.gif](upload://zEgbBCXRskkCTwEux7Bi20ZySza.gif)


--
Dave Bush
MAB Member

"LIFE'S TOUGH, WEAR A HELMET"

Originally Posted By: jpope
This post was automatically imported from our archived forum.



Darn, missed another one . . . icon_confused.gif



Jeff Pope


JPI Home Inspection Service


“At JPI, we’ll help you look better”


(661) 212-0738

Originally Posted By: Blaine Wiley
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Well Dave you can say the answer is A if you want, but it is B.


York units come with the Honeywell fan control high limit combination switch with the fan off set at 90, the fan on set at 115 and the high limit preset at 200. The Bryant furnace I just did this morning had a limit switch rated at 200 -25, meaning the limit trips at 200 and resets at 175.

I just looked in one of my inspection books, and it shows a diagram of the Robertshaw switch and it has presets at the same as the York system, and states the high limit setting on most furnaces is 200 degrees.

Oh well, at least I only see two or three gas furnaces per year. ![eusa_wall.gif](upload://hILV5Z8gRVLwzVpRIDJEm01uB52.gif)


Originally Posted By: cradan
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more often “A”, but can be (and sometimes is) “B”. Highly dependent on furnace design/spec. and controls mfr.



Chris


http://www.inspect4me.com


Chicago Illinois Home Inspections

Originally Posted By: rcooke
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I wonder how many look to see what is on the furnace .


Is it above what we should be doing ???


I know I do look at some but not all.


Roy Cooke sr.


Originally Posted By: jfarsetta
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I do not look for it. How would we test it.



Joe Farsetta


Illigitimi Non Carborundum
"Dont let the bastards grind you down..."

Originally Posted By: Blaine Wiley
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I just note if they aren’t there or aren’t hooked up. I have found them not connected. The Robertshaw and Honeywell ones make it easy to see if the furnace is cycling on high limit, you can just watch the dial!


Originally Posted By: syared
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So if I understand this correctly, the high limit is typically 150 degrees, but can be higher based on manufacturers specs. If that’s the case how can we check or report on this if the answer relies on knowing the specs of each furnace, that’s getting too technical and out of our scope, right?


Originally Posted By: Guest
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I’ve bought about 100 of these things over the years and without exception every one came preset at 200.


Originally Posted By: jsavino
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Joe, You would have to disconnect the load side of the switch. I have installed mostly the Honeywell fan/ limit control. All came pre-set at 100 degrees blower off, 150 degrees blower on and 180 degrees limit.


The newer furnaces come through with a circuit board fan control center that operates by time. Some mounted in the blower compartment. You still have a limit control, but just a mechanical switch, wired to a relay that could be set up to 90 seconds from when the furnace comes on. Regardless if the burners fire up or not. So in the case of a burner malfunction the blower will still start and run for a while.


Manufactures installed these controls to extend the life of the heat exchanger. Only one problem for the service man (Me) that if the blower doesn’t operate, you replace the circuit board. Instead of the F/L switch.



John Savino


HomeWorks Inspection Services, LLC


St. James, NY


631.379.4241