GE Monogram 3900 Series manual General Installation Suggestions, Electrical Wiring Installation

General Installation Suggestions

Many times poor or non-existent caulking around the exterior of the wall case results in air infiltration causing the unit to run excessively. One way to check for air infiltration is to look under and around the unit to the outdoors. If you can see light, there is air infiltration. The first floor of a building is where this problem most frequently occurs since caulking the bottom of the wall case may require lying outside in the dirt while working. This has been the cause of many complaints about the “short cycling” of the Freeze Sentinel™.

Curtains, furniture or other obstructions interfering with the discharge air circulation will make the unit cycle turn off too soon since the cooled (or heated) discharge air is pulled back into the unit. This results in a room that is not adequately heated or cooled.

Blocking the discharge air on the left side during heating operation can result in the air getting hot enough to distort the plastic room front. If you have a property where this may occur we recommend a “tent card” advising room occupants not to put anything on the unit.

Electrical Wiring Installation

Do not allow the installer to drill a hole in the wall case to run the electrical wiring. If this is done, the wiring will have to be run between the chassis and the edge of the wall case so it can be connected to the unit wiring on the room side of the wall case. When the chassis is removed for servicing or cleaning, the insulation on the wires can be cut and can create a safety hazard.

If the electrical connection on a 230-volt or 208-volt installation is to be made by the line cord plugged into a wall-mounted receptacle, the receptacle should be located in the wall under the case or close to the side of the wall case. This installation makes a much neater appearance than a line cord running a foot or more across the floor. The electrician may want to place the receptacle as far from the unit as possible to save a few feet of wiring without considering how the installation may appear.

Central Desk Control and Remote

Thermostat Wiring

Do not allow the installer to drill a hole in the wall case to run Central Desk Control wiring or remote thermostat wiring to the unit terminals. CDC and remote thermostat wiring is classified as low-voltage wiring and does not have to be run in conduit unless required by local code. CDC and remote thermostat wiring should be run in the walls and exit the wall under the wall case about 2" from the right-hand side. The base pan is designed with a clearance for the line cord and the low-voltage wiring can be run to the chassis in this area also. Wire molding can be used to hold the wiring close to the bottom of the wall case. If a sub-base is used, the wiring can be run through the sub-base, entering the rear and exiting through one of the front panels. When the room cabinet is in place the CDC or remote thermostat wiring is usually not

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visible to someone standing or sitting in the room. Do not run the low-voltage wiring in conduits with line-voltage wiring or near uninsulated line-voltage wiring since induced current can interrupt the low-voltage controls.

Consult the electrical inspector early in the project, especially if the power to the air conditioner is to be 265 volts, to understand what is required to comply with local electrical codes.

Wall Case/Exterior Grille

When making an installation where the exterior grille is flush with the exterior wall, or part of a custom window/louver section, make sure the installer caulks the wall case to the exterior wall, especially the bottom of the case. Many times the air conditioners are run during construction and the building is not closed. This can result in excessive humidity from the warm humid air entering the building, or from the “drying out” of the building materials. Many problems have been caused by condensate water or rainwater running back into the building where proper caulking has not been done.

Capacity Considerations

A unit that has a greater cooling capacity than required will cool the room quickly but will usually not run long enough under normal operation to adequately dehumidify the room. Most musty odors in rooms are due to excess humidity. Using a smaller capacity unit or using Dry Air 25 units will provide better dehumidification. The largest factor in causing mold and mildew in the room is excess moisture, and a smaller unit running longer or a Dry Air 25 model can remove more moisture. Mold behind wall coverings that do not allow water vapor to pass through — vinyl wallpaper or oil-base paints, for example — is not a problem of excessive moisture in the room, but rather is caused by moisture trapped in the walls.

Using a resistance heater larger than required — using a 5 kW heater when a 3.45 kW heater would suffice for example

—may not cost any more in electrical consumption since the larger heater will operate for less time. The “Demand Charge” portion of the utility bill — which is based on the highest electrical load for a period of time — may be a significant portion of the utility bill. Some customers have reported the “Demand Charge” actually being more than the usage charge. In a 100-room property it would be possible for the demand of the 5.0 kW heater versus a 3.45 kW heater to be 155 kW more than the demand charge if the lower wattage heaters were used. Working with the utility companies to understand their method of billing and taking advantage of any rebates they may offer can reduce the utility bill.

Exterior Grilles

When replacing an older unit the existing outdoor grille may need to be changed or modified. Outdoor airflow patterns have changed and this may dictate the need for outdoor grille replacement or modification.

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