1. Give yourself room: From within the walk-in, locate the center of the 10-3/8" diameter hole to be cut through the wall, ceiling or floor. Keep the center at least 12" from any corner. As you can see from the drawing, the holes are not completely round. The intake hole has a notch on the bottom (if in a wall) to accommodate the outside sensor wire. Each has a notch on the top (if in a wall) for the conduit connecting the electrical box to the fan, so extra room beyween the center of the circle and an adjoining surface will allow room for this. This also avoids many interior structural members which often are found where two panels or surfaces meet. The studs of a site-built walk-in cooler may or may not be lined up with the studs in another wall right next to it. Check both sides before cutting the holes to make the job easier.
2. Pilot hole: Drill a 1/4" hole completely through the cooler's wall or ceiling with a long drill bit, to establish the center of each duct hole on the far side. Keep the bit as horizontal or vertical as possible.
3. Draw the holes to be cut: With the 1/4" hole as the center, draw a circle with a radius of 5-3/16" (10-3/8" diameter) on each side of the wall or ceiling, for each duct hole. Add the appropriate notches for the electrical conduit and sensor tubing. You may also use a template to draw these lines.
4. Cut the holes: For the most accuracy, each hole should be cut from each side of the wall or ceiling. A typical manufactured walk-in cooler panel has two aluminum faces sandwiching a 4" core of urethane foam. The metal is easily cut using a sharp hand chisel from each side and a keyhole saw to cut the foam. You can also use a jigsaw (with an appropriate wood or metal blade). There may be situations in which access on the far side of the cooler wall, floor, or ceiling is difficult or impossible. A Sawzall-type saw with a long blade can be used from the walk-in cooler side of the wall or ceiling. This is generally not the first choice of hole-cutting methods as precision is sacrificed. Always use goggles or other eye protection when cutting and keep them on even after you are done cutting as a sudden rush of air through the hole can easily carry particles of metal or other irritants into your eyes. You will hate it when that happens!
5. Repeat as necessary: Repeat steps 1-4 for each wall, ceiling, or roof that must be penetrated in order to reach the outside. Remember that there will be no need for notches for the conduit or sensor wire tube in any walls beyond the intake or exhaust fans, so those holes can simply be round circles. You can put away the saw when there is a passageway for each intake and exhaust unit from the inside of the walk-in to the outside.

Installing the Intake Unit:

The outside sensor wire is threaded from the outside in. The sensor is attached to the extension cable at the factory, is larger than the wire, and won¹t fit through either of the sensor wire tubes that bypass the filter (shown at left) or through the strain relief connector in the flange of the intake damper housing. It must be threaded from the intake wallcap back to the Cooler Controller. When installing the various components of the intake unit, keep in mind that the sensor wire must be in place before any component becomes inaccessible. Also, be sure that any sensor wire tube is not crimped or crushed when installing a component or the sensor will not be able to be pushed through it. It is not essential that the outside sensor be run through the intake unit, but it is usually the easiest route to the outside. It will also always measure the correct temperature of the incoming air. If a location for the outside sensor other than the intake wallcap is chosen, be sure that the sensor and wire are well protected along their entire length. The sensor should be in a place that will have the same exposure to the sun and the same temperature as the air that is entering the intake wallcap.

Installing the intake fan: Wire the intake fan before mounting the housing around it so it will be easier to make the wiring connections. If the 36" of liquid-tight conduit supplied is not long enough to reach from the intake damper housing to the intake fan, you will need to supply your own. Be sure the fan is securely fastened to either the duct or the intake damper housing that is itself securely fastened in place.

Installing the Intake and Exhaust Damper Units:

Leave 2" of duct projecting from a surface. This leaves room to attach an insulated duct, the intake fan, or an optional angle ring if more support is needed. One exception to this is the exhaust housing, which may project up to 6" from a 4" thick walk-in cooler panel. If necessary, the wallcap will accommodate even this much projection through the outside wall, but normally 2" is all that you need to leave sticking into the wallcap.

Working with uneven surfaces: Uneven surfaces (such as clapboards) should be removed until a flat surface is reached in order to attach intake fan housings, filter housings, or wallcaps. Minor holes and gaps can be sealed with a high quality caulk if the foam gaskets are not suffficient. The optional insulated end panel (item # 537) may be used to make a sealed transition from a 10" duct through a wall to the intake fan or filter housing if it isn¹t possible to seal an uneven surface around the perimeter.

Make it tight: Every joint throughout the system should also be completely wrapped with duct tape to keep cold air from escaping from a duct or warm air from entering it.

Using the spring tensioners: When installing an intake damper housing in the ceiling or an exhaust fan housing in the floor of a walk-in cooler, you will notice that the damper flaps do not close. This is because in these positions the damper return spring is not strong enough to overcome the weight of the insulated dampers. In these cases the spring tensioner, included in the small parts bag, should be placed under the spring and attached to the center post. This should allow the dampers to close snugly.

Remove the damper return spring when it is not needed: When installing an intake damper housing in the floor or an exhaust fan housing in the ceiling of a walk-in cooler the damper return spring is not needed because the weight of the insulated dampers do a good job of keeping the dampers closed. Having the spring in place just makes it harder for the fans to overcome the combined force of gravity and the spring tension, and makes the outside air system less effective.

Summer plugs and adjustable elbow: These may be attached to the wall adjacent to the intake damper or exhaust housings by a screw through the 12" chain provided. It is easiest if they can be put into place or removed without detaching the chains from the wall. If storing them in place like this is not possible, be sure to keep them where they will not be lost or forgotten.

Flat Roof Vent Package (#520) Be sure that both the intake and exhaust caps are well above any potential snow build-up on the roof. Simply add 24" lengths of 10" 24 gauge galvanized round pipe until a sufficient height is reached. If you are unsure if you can make the penetrations of the flat roof absolutely watertight, consider using a professional roofing company. Often a roofing company will already be guaranteeing a roof against leakage, provided nobody but they makes any hole it. Check with the building owner before cutting.

CHECKLIST WHEN FINISHING AN INSTALLATION

• Every component is securely attached in place.____
• Each duct is insulated____
• and tightly sealed with duct tape.____
• All wiring connections are tight.___
• Test fit of summer plugs for tightness.___
• Dampers close snugly.___

Warning Stickers: There are several enclosed warning stickers that can be applied where they will be seen. The "CAUTION: FREEZING COLD AIR" sticker can be attached to the front of one of the intake dampers, or to the adjustable elbow if there is one, to keep people front blocking the flow of outside air into the cooler. Most importantly, the "FILTER MUST BE CHANGED AT LEAST ONCE A YEAR" sticker must be attached where it will be seen often, perhaps on the filter access door, the door of the Cooler Controller, or even the door to the walk-in cooler.

Specifying Planning Installing Wiring Cooler Controller Commissioning & Troubleshooting Maintaining