The high-velocity system distributes conditioned air by means of flexible, pre-insulated, 2-inch inside diameter tubing, which is fed through wall structures and around obstructions. The system uses sound attenuation materials that absorb airborne and regenerated noise and provide a quiet comfort system.
The heart of the system is a single cabinet blower and coil air handler that is designed to fit in tight spaces while providing efficient cooling and heating from its refrigeration coil.
The 10 steps to a successful installation are:
SpacePak provides a “Kwik Way” sizing form that is designed to accurately provide a room-by-room load for the high-velocity system. Also offered is an “Informer” CD including calculation software.
Now that the system has been properly sized for the structure, we can begin our equipment installation.
One must also consider the location of the return air filter box and duct. Another important consideration is the location of the 9-inch inside diameter plenum, air supply tubing, refrigerant lines, and condensate drain line.
When installing a fan coil unit in an attic space, such as above a ceiling, it is recommended to install a secondary drain pan and/or a float switch. Again check your local codes for this requirement.
The unit may be installed on a platform or suspended from a pre-assembled suspended platform. The platform (fixed or suspended) must be close enough to the selected return air box opening for ease of connecting the return air plenum duct (see below for platform instructions).
The return air box is designed to fit between joists that are 16 inches on center with a 14-inch width. For wall applications such as when using a vertical free-standing fan coil unit, be sure the opening will allow for a 90-degree bend in the return air duct. Next check for proper fit of your return air box. However, do not install the return air box until your installation is complete because you may want to pass materials for your installation through this opening.
For locations where the fan coil unit must be suspended, suspend the platform overhead by 1/4-inch threaded rods. Never connect a threaded rod directly to the fan coil cabinet. It’s not necessary to secure the fan coil unit to the platform because the weight of the unit will hold it in position. Remember to leave room for servicing.
Plenum duct installation, all tees, elbows, and branch runs must be a minimum of 18 inches from the fan coil unit and any other tee, elbow ,or branch supply run. It is recommended that you keep the use of tees and elbows to a minimum to keep the system pressure drop to a minimum. The plenum duct comes in 6-foot lengths and may be cut to desired lengths depending on your system layout.
When installing the plenum to the unit, it is recommended you cut off the male end of the first section. Then insert the plenum duct section into the receiving collar on the fan coil unit. Be sure to push the duct in tight to form a snug joint. Then flatten the sheet metal tabs against the plenum duct and insert the flat head pins. Next, wrap and tape in place the 6-inch-wide piece of foil face insulation over the taped joint. Be sure the insulation is pushed up against the fan coil unit.
Continue to assemble the plenum duct making sure the “shiplap” joints are snug and taped securely. (Polyken #222 tape or equivalent is recommended.) Once your plenum duct has been installed, the plenum end cap will now go on the end of your plenum run. The plenum end cap contains an insulated cushion that is pushed up tight against the duct end. Hold the end cap firmly in place, then insert the flat head pins through the sheet metal tabs at the end of the cap. Cross-tape the end cap securely with a circumferential wrap around the end cap. It’s always a good idea to strap or cradle the plenum to avoid plenum movement during operation, which could cause joints to come loose.
Next assemble the room terminator to the sound attenuating tubing by fitting the connectors together and twisting until tight. If the terminator is being installed in a floor location, you must fabricate a small 1/4- by 1-1/2-inch-square screen and place the screen between the terminator faceplate and the tubing connector. Then push the free end of the sound attenuating tubing through the 4-inch hole until the toggles on the terminator snap into place. Center the two spring clips on a line parallel to the direction of the tubing so the faceplate doesn’t pull away from the ceiling.
At the plenum location you have selected, cut a 2-inch hole in the plenum with the hole cutter supplied. Be sure that your hole is at a 20-degree down angle to eliminate a strain on the plenum. To cut the hole with the hole cutter, rotate the cutter back and forth, applying just enough pressure to force the serrated edge into the foil and insulation of the plenum. Remove the hole cut out from the plenum. Be sure there is no flap left that could block the hole during operation.
Next, place the plenum takeoff gasket around the hole. Then place the plenum takeoff connector into the hole in the plenum. Orient the plenum takeoff to match the curvature of the plenum duct. Insert the plenum fasteners by hand one at a time. Using pliers, snap the fasteners into place. Once the plenum takeoff is in place, you’re ready to install balancing orifices if necessary. Next, install a connector into the remaining open end of the supply tubing following the same procedure as before. Then connect the connector from the tubing to the plenum takeoff following the twisting action used to connect the connectors. You have now completed your supply run.
Once you have completed your supply run installations, you can begin to install your return air duct and return air box. Remove the return air grille and filter from the return air box assembly. Insert the return air box into the return air opening you cut earlier and fasten the frame with four screws through the holes provided on the long side of the box. Then, insert the return air grille into the box and fasten with the four screws provided. Open the grille and insert the filter. Then connect each end of the return air flexible duct to the elliptical end of the fan coil and the return air box connections with the clamp bands.
Lewis is product manager for SpacePak, a Mestek company. For additional information, contact: SpacePak, 260 North Elm Street, Westfield, MA 01085; 413-564-5530; 413-564-5815 (fax); www.spacepak.com.
Publication date: 03/10/2003