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HVAC Forums => HVAC Help => Topic started by: wantboost on September 08, 2019, 09:12:10 AM

Title: Shelf clearance to combi unit
Post by: wantboost on September 08, 2019, 09:12:10 AM
How far should clearance be from furnace /supply from this unit on on perpendicular wall .
Where can I find this in the code ?

(https://i.ibb.co/yF2C9kw/20190908-101428.jpg) (https://ibb.co/yF2C9kw)
Title: Re: Shelf clearance to combi unit
Post by: Sergroum on September 08, 2019, 03:27:02 PM
I'm not fully sure what you mean.


There needs to be 24 inches in front of the unit. So for example that chair is against code theoretically :).

The ductwork can be closed in however you want, it does not require any clearances. Although I would keep the same 24 inches clearance to the evaporation coil.
Title: Re: Shelf clearance to combi unit
Post by: wantboost on September 08, 2019, 03:38:59 PM
I wanna put wood/melamine shelves on the wall they will protrude outwards towards the duct work /supply air plenum and or top of the furnace.  Is there a minimum clearance for fire safety
Title: Re: Shelf clearance to combi unit
Post by: Frosty on September 08, 2019, 04:30:57 PM
Looks like an air handler to me! Look in the installation manual for the clearance to service.Usually in the first few pages. Good practice to leave at least 24'' to the  front  of that piece of equipment if it ever needs to be serviced
Title: Re: Shelf clearance to combi unit
Post by: wantboost on September 08, 2019, 04:33:02 PM
My.concern is clearance from the duct work and the grey/black part
Title: Re: Shelf clearance to combi unit
Post by: Admin on September 08, 2019, 04:53:56 PM
If the shelf protrudes off the wall and interferes with the 24" serviceability in front of the furnace it would be against Code, unless the shelving can be removed easily.

Most appliances have 0" clearance to the sides.  The Ontario Building Code is not very clear but see Articles 6.2.3.2 and 6.2.4.10.  The SMACNA handbook is a little more clear.  Rule of thumb is to provide 1" clearance from the plenum to combustible material for the first 18" off the furnace.  It's really nothing to worry about it because there is no risk of fire and no inspector will ever enforce this.

As long as the clearances listed in the appliance manual are followed you will have no problems.


Title: Re: Shelf clearance to combi unit
Post by: Sergroum on September 09, 2019, 12:05:22 PM
In general, you don't want to close in the coil (the dark grey box on top of the unit), as it will need work done on it eventually. But if it's shelves and they are theoretically removable, it'll be fine.b the issue is not fire hazard. The issue is serviceability.
Title: Re: Shelf clearance to combi unit
Post by: wantboost on December 05, 2019, 03:31:08 PM
First 18" of the plenum ?
Quote from: Admin on September 08, 2019, 04:53:56 PM
If the shelf protrudes off the wall and interferes with the 24" serviceability in front of the furnace it would be against Code, unless the shelving can be removed easily.

Most appliances have 0" clearance to the sides.  The Ontario Building Code is not very clear but see Articles 6.2.3.2 and 6.2.4.10.  The SMACNA handbook is a little more clear.  Rule of thumb is to provide 1" clearance from the plenum to combustible material for the first 18" off the furnace.  It's really nothing to worry about it because there is no risk of fire and no inspector will ever enforce this.

As long as the clearances listed in the appliance manual are followed you will have no problems.
Title: Re: Shelf clearance to combi unit
Post by: Admin on December 05, 2019, 04:16:21 PM
Well it's more the takeoffs and trunk line that run horizontally.  The plenum as well as those ducts within the first 18 inches from the furnace require 1 inch clearance from combustible material.