After louvers are installed, start up of the air system may reveal louver issues that require attention. Stationary-blade louvers have no moving parts. Therefore, they generally present few problems during operation. Operable louvers have a few more potential problem areas. Following are common louver-operation obstacles and methods for overcoming them.
Not enough airflow through louvers. Assuming the louver is sized correctly, with the proper amount of free area, this is caused mainly by obstructions in the louver and/or bird screens. Remove any debris that has accumulated on blades and screen. Also, if applicable, check to see if blank-off panels are in the proper locations.
Excessive water penetration. Be sure sealant has been properly applied around the louver perimeter and other required locations. For drainable louvers make sure the drain holes in the frames are not obstructed. Also, check that proper flashings and end sills are in place.
Operable louver blades do not move. Check that all actuators are connected and energized and getting the proper voltage. Be sure all linkages are connected and secure. Examine the louvers to make sure that the installation fasteners are not preventing linkage movement. Check the squareness of the louver. Measure diagonally from corner to corner; the dimensions should be within 1/16th of an inch. If the difference is more than that, the added torque created by the out-of-square configuration may be more than the actuator can overcome. This problem is difficult to overcome and it is best to loosen all fasteners and re-adjust to get it oriented squarely. During installation, the jamb frames potentially could have been pulled inwards when secured to the wall. This creates added operating torque similar to out-of-square. To fix the problem, loosen the installation fasteners, pull the jambs outward toward the wall until they are straight, and re-secure all installation fasteners. While fairly uncommon, actuators can be defective; if so, contact the actuator supplier.
Not enough movement of operable blades. Check for obstruction in linkages or blades. Remove objects that are lodged in blades. The problem may be in the linkage assembly. Unlike control dampers, most operable louver blades do not move a full 90 degrees. Therefore, linkage adjustment is critical. They may require some fine tuning in the field. After louvers are installed and in operation, little maintenance is required during their lifespan. Following are some periodic maintenance tasks to ensure maximum performance from your louvers:
- Check bird screens and remove accumulated trash and obstructions.
- Grime buildup on anodized and painted louvers accelerates deterioration of the finishes. Clean thoroughly after construction and occasionally during lifespan.
- Cycle operable louvers periodically to verify that louver blades open and close.
Proper documentation should be kept on file to verify project specifications are met. Catalogue submittal sheets are usually a good reference document. The performance of your louvers should be supported by AMCA testing and certification. AMCA has developed test standards and certified ratings programs for many air devices. AMCA Standard 500-L-99 and Publication 511 define the requirements for louver performance certification. Products may display the AMCA performance seals only after they have been independently tested. The AMCA Seal ensures that the louvers in question meet all established standards.
Specifying AMCA certified louvers and having them installed by qualified SMACNA contractors is the most effective way to ensure louvers perform as specified.