Lay-In Grilles

Return grilles, and sometimes supply grilles, are specified for lay-in applications. If the grilles are to be connected to ductwork, a grille size is specified as well as the lay-in module size.

Most Titus grilles can be ordered in a lay-in frame style. When the size of the grille is less than “module size minus 2”,” the grille must be panel mounted. Panel mounting is welding a grille of a specific size to the rear of a panel designed to mount in a lay-in grid module. This provides a unit sized to the grid opening with a grille size for the ductwork. Using a 24”x24” lay-in frame as an example with a 12”x6” grille, you would go into the ordering software, select the appropriate model grille, and enter 12” (width) and 6” (height). Next, change the module size from “NONE,” to 24”x24”. The frame type will automatically change to “TYPE 3 - LAY-IN,” and the fastening option will change from the default “A - SCREW HOLES,” to “NONE.” You will also notice a price increase for the panel mounting.

As mentioned previously, this works for grilles with a size less than “module size minus 2”,” i.e.: a 16”x16” grille in a 24”x24” module size. But, what if the return grille specified does not have a specific size and only the module size is specified (usually indicating a non-ducted return application)? Or, you need a grille that is actually specified with a size of “module size minus 2”,” like a 22”x22” grille for a 24”x24” module?

In the order-entry software, you enter 22” (width) and 22” (height). The module-size option will not let you enter 24”x24”. The answer is simple with just a little bit of grille knowledge. All grilles have overall dimensions of size plus 1 ¾”, so a 22”x22” grille results in an overall dimension of 23 ¾” x 23 ¾”, which happens to be the overall dimension of a type 3 lay-in frame for a 24”x24” module.

Although the frame style will remain shown as “1 - SURFACE MOUNT,” the unit will work perfectly in a lay-in application. The most important thing to remember is to change the fastening option from the default “A - SCREW HOLES,” to “0 - NONE.” We have no way to remove holes from a frame after the grille has shipped, and most customers do not want visible mounting holes in the face of a lay-in product. So, if the return grille is for a non-ducted application -- or a specific grille size is not specified, only the module size – order the grille size as “module size minus 2”.” Not only will you get a full-face return that is much more aesthetically appealing, but it is cheaper!

We offer a range of panels for common lay-in grid module sizes in three different frames, but occasionally a non-standard module size or an NT frame style is required. This is not a problem, as you should simply use your Titus Contact Directory to submit the request to one of our GRD application engineers. We routinely provide NT and non-standard module frames upon request. Renderings may already be available that can help verify your customer’s product requirements. A slight up-charge is required and the special units can usually be supplied in standard lead times. 


Please direct questions toward Titus Communications (communications@titus-hvac.com) and/or Titus' GRD Product Manager Mark Costello (mcostello@titus-hvac.com).