# VAV



## dcspector (Jan 30, 2010)

Would a VAV (Variable Air Volume ) box fall under 422 or 440? I have had the opportunity to read several inspecton reports from other juridictions and the section numbers have been inconsistent.


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## chris kennedy (Jan 31, 2010)

Re: VAV



> Appliance. Utilization equipment, generally other than industrial, that is normally built in standardized sizes or types and is installed or connected as a unit to perform one or more functions such as clothes washing, air conditioning, food mixing, deep frying, and so forth.


Thats questionable.



> 440.1 Scope.The provisions of this article apply to electric motor-driven air-conditioning and refrigerating equipment and to the branch circuits and controllers for such equipment. It provides for the special considerations necessary for circuits supplying hermetic refrigerant motor-compressors and for any air-conditioning or refrigerating equipment that is supplied from a branch circuit that supplies a hermetic refrigerant motor-compressor.


Hmm, no compressor in a VAV.

How about 430?


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## dcspector (Jan 31, 2010)

Re: VAV

Yeah Chris I was leaning more to 422.


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## dcspector (Jan 31, 2010)

Re: VAV

I forgot to mention what if it contains a reheat system? Then could one use 424?


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## chris kennedy (Jan 31, 2010)

Re: VAV



			
				dcspector said:
			
		

> I have had the opportunity to read several inspecton reports from other juridictions and the section numbers have been inconsistent.


What are you questioning? Could you give a brief example of the inconsistent numbers that caught your eye?

Also, very odd that an inspector would spell 'inspection' and 'jurisdiction' wrong yet spell 'inconsistent' correctly. :lol:


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## D a v e W (Feb 1, 2010)

Re: VAV

Curious what is the issue with the report  :?:

Words spelt wrong, happens on this board all the time. No spell check that I have found  :lol:


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## dcspector (Feb 1, 2010)

Re: VAV



			
				chris kennedy said:
			
		

> dcspector said:
> 
> 
> 
> > Also, very odd that an inspector would spell 'inspection' and 'jurisdiction' wrong yet spell 'inconsistent' correctly. :lol:


I was probably sober... :lol:


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## dcspector (Feb 1, 2010)

Re: VAV

Chris and Dave,

This is regarding disconnecting means for the VAV. Usually the VAV's I deal with have the resistive heat strips/coils. Now with that said the units have the incorporated unit switch per 424.19© is what is and should be accepted. However, the EC's in my area are getting gigged in the surrounding areas for not field providing an additional disconnect. In summarry all I have seen on the other reports were anywhere from rediculous, to 422, 440..


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## raider1 (Feb 1, 2010)

Re: VAV



			
				dcspector said:
			
		

> Chris and Dave,This is regarding disconnecting means for the VAV. Usually the VAV's I deal with have the resistive heat strips/coils. Now with that said the units have the incorporated unit switch per 424.19© is what is and should be accepted. However, the EC's in my area are getting gigged in the surrounding areas for not field providing an additional disconnect. In summarry all I have seen on the other reports were anywhere from rediculous, to 422, 440..


I agree with you on using Article 424 if the VAV has heat strips and 424.19© specifically allows the use of a unit switch as the required disconnecting means.

If the VAV did not have a heat strip or coil then my feeling is that 422 would apply and 422.34 would allow a unit switch to be used as the disconnecting means.

Chris


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## dcspector (Feb 1, 2010)

Re: VAV

Thanks C.J./Raider

I am sorry to be so evasive in my op, but I was trying to get a bit of consensus regarding how one classified a VAV before giving more detail. In summary, I was on a job last week and was looking at redundant disconnects for the VAV's, heck there were 10 per floor and 12 floors to boot! All I mentioned was, "why did you install the additional disconnects"? and the story unfolded. I see this as a lack of code education and or misinterpretation on the inspectors part. Also, the additional material and labor costs the owner had to absorb.......  :shock:

Thanks all, just wanted to share with you.


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