# Fresh air intake



## ICE (Mar 26, 2013)

The lower hood on the side of the unit is an air intake.  The plumbing vents are required to be two above or ten feet away.  A general building contractor did this so he didn't know that.  Now he says that the air intake is an option and he plans to block it.  I asked for the manufactures instructions.


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## Gregg Harris (Mar 26, 2013)

ICE said:
			
		

> The lower hood on the side of the unit is an air intake.  The plumbing vents are required to be two above or ten feet away.  A general building contractor did this so he didn't know that.  Now he says that the air intake is an option and he plans to block it.  I asked for the manufactures instructions.


 IPC 904.5 for vent termination would be for fresh air intake and the lower hood is for combustion intake air and the upper is combustion discharge.

The condensate  drain does require a trap


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## Gregg Harris (Mar 26, 2013)

Ice it is hard to tell but it does not appear to have a sediment trap on the gas line and I would question the blocking being secured and the flexible appliance connector, also whether or not the connector is listed for outdoor use. ANSI Z21.75/CSA 6.27


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## ICE (Mar 26, 2013)

Gregg Harris said:
			
		

> Ice it is hard to tell but it does not appear to have a sediment trap on the gas line and I would question the blocking being secured and the flexible appliance connector, also whether or not the connector is listed for outdoor use. ANSI Z21.75/CSA 6.27


Gregg,

We seldom ask for sediment traps on residential but just yesterday, I ask for trapson a bank of tankless water heaters at a laundry.  You are right about the blocks and I think the connector is ok outdoors but I will check on that, thanks.

Other corrections were a lack of a receptacle within 25' and the original disconnect is breakers that are not HACR type.



			
				Gregg Harris said:
			
		

> IPC 904.5 for vent termination would be for fresh air intake and the lower hood is for combustion intake air and the upper is combustion discharge.The condensate  drain does require a trap


Now I don't know for sure but I thought that the lower hood is for fresh air dilution into the building.  Never require a trap on the condensate.  Maybe I should.


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## ICE (Mar 26, 2013)

I went there today and Gregg is right, it is a combustion air intake.  It seems to me that the units used to have a fresh air intake but not this one.  Oh well, I was wrong yet again.


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## Gregg Harris (Mar 26, 2013)

ICE said:
			
		

> I went there today and Gregg is right, it is a combustion air intake.  It seems to me that the units used to have a fresh air intake but not this one.  Oh well, I was wrong yet again.


Ice on the condensate trap, the depth of the trap will negate the negative pressure of the indoor fan and will prevent the condensate from overflowing into the structure. I do not know of any manufacturer of a package unit that does not require one.


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## ICE (Mar 26, 2013)

There it is.






Gregg,

Please help me understand the difference a trap will make on a package unit as opposed to a split system coil.  I asked around and the other inspectors haven't been requiring a trap either.  The common held belief is that a trap is to prevent the escape of sewer gasses into a building or appliance.  We allow condensates to drain outside or to a tailpiece which is protected by a trap.  I see traps, traps with vents and straight runs.  They all drain by gravity.  You mentioned negative pressure and that's where you lost me.  I would think that the air flow over the coils would create positive pressure.  Now if that were the opposite and there is negative pressure, I don't understand how a trap seal would aid the flow by gravity.

Thanks


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## Gregg Harris (Mar 26, 2013)

ICE said:
			
		

> There it is.
> 
> 
> 
> ...


The condensate drain is on the negative side of the blower "or return side" as the air is pulled across the coil if there is not a trap on the drain that negative pressure will pull air up through the pipe preventing water from exiting the unit. if the unit has a negative static pressure of 0.3 inches of water column, the height of the water seal in the trap would need to be slightly higher to offset the indoor blower motor.

This will also happen on split systems if the air is being pulled across the coil as apposed to blowing across. I always teach to install a trap on all split systems to prevent sewer gas from entering if the plumbing water seal is lost in the floor drain, and it will also prevent bugs from entering.


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## Keystone (Mar 27, 2013)

Don't forget about coating / painting that black iron pipe.


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## Zebra (Apr 10, 2013)

Guess what happens to that condensate trap on the first freeze?


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## Builder Bob (Apr 10, 2013)

I don't know....... We unusually get down to about 35 degrees for our night time lows..........Darn, living at the beach in the south..... it's almost 5 o'clock somewhere


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## north star (Apr 10, 2013)

*: = : = :*

Zebra,

*1st, *...Welcome to The Building Codes Forum! 

*2nd,* ...Not a significant probability for freezing in ICE' location [ sunny

SoCal ], plus, the manufacturer' installation requirements do require an

external trap.....See Post # 7.

*: = : = :*


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