Carrier 50EZ manual Maintenance and Service, Fire and Unit Operation Hazard

sorbed from the outside air. So, to maintain energy-efficient opera- tion, your unit has an automatic defrost mode.

The defrost mode starts at a preset time interval of 60 minutes, al- though, it may be reset to 30, 90 or 120 minutes. Defrost will start at the preset time only if the ice is sufficient to interfere with normal heating operation.

After the ice is melted from the coil, or after a maximum of 10 min- utes in defrost mode, the unit automatically switches back to normal heating operation.

Do not be alarmed if steam or fog appears at the outdoor unit during defrost mode. Water vapor from the melting ice may condense into a mist in the cold outside air.

During certain weather conditions such as heavy snow and freezing rain it is not uncommon for ice to build up on the unit grille. This is normal for these weather conditions. Do not attempt to remove the ice from the unit grille. This condition will not affect the proper function of the unit and will clear within a few days.

Emergency Heating Mode

In the event of primary unit heat failure, the emergency heat mode allows your supplemental heating source to keep your home or of- fice warm until your unit can be serviced. Contact your dealer in the event of primary unit heat failure.

MAINTENANCE AND SERVICE

This section discusses maintenance that should be performed by your dealer and care you, as the owner, may wish to handle for your new unit.

Routine Maintenance

All routine maintenance should be handled by skilled, experienced personnel. Your dealer can help you establish a standard procedure.

To assure proper functioning of the unit, flow of condenser air must not be obstructed from reaching the unit. Clearance from the top of the unit is 48 in. (1219 mm). Clearance of at least 36 in. (914 mm) is required on sides except the power entry side (42 in. clearance) (1067 mm) and the duct side (12 in. minimum clearance) (305 mm).

Maintenance and Care for the Equipment Owner

Before proceeding with those things you might want to maintain yourself, please carefully consider the following:

!WARNING

FIRE, EXPLOSION, ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury, death or property damage.

1.TURN OFF ELECTRICAL POWER TO YOUR UNIT BEFORE SERVICING OR PERFORMING MAINTENANCE AND INSTALL A LOCK-OUT TAG.

2.When removing access panels or performing maintenance functions inside your unit, be aware of sharp sheet metal parts and screws. Although special care is taken to reduce sharp edges to a minimum, be extremely careful when handling parts or reaching into the unit.

Air Filters

The air filter(s) should be checked every 3 or 4 weeks and changed or cleaned whenever it becomes dirty. Dirty filters produce exces- sive stress on the blower motor and can cause the motor to overheat and shut down.

This unit must have an air filter in place before it can be operated. These filters should be located in at least one of two places. In many applications, the installer will provide return air filter grilles mounted on the wall or ceiling of the conditioned structure. In the

instance of filter grilles, the filters can simply be removed from the grille and replaced.

The other typical application is an accessory filter rack installed in- side the unit itself. The following information is given to assist in changing filters used in these internal filter racks.

Table 1 indicates the correct indoor filter size for your unit. Refer to Fig. 2 to access filters installed in the accessory filter rack. If using an Accessory Filter Rack, refer to the Installation Instructions pro- vided with it for correct filter sizes and quantities.

Table 1—Air Filters Located Inside Unit

(For Replacement Purposes)

Unit Size	Filter Size in. (mm)
50EZ024	20x20x1 (508x508x25)
50EZ030	20x24x1 (508x610x25)
50EZ036--- 042	24x30x1 (610x762x25)
50EZ048--- 060	24x36x1 (610x914x25)

To replace or inspect filters in accessory filter rack:

1.Remove the filter access panel (See Fig. 2) using a 5/16-in. nut driver.

2.Remove the filter(s) by pulling it out of the unit. If the filter(s) is dirty, clean or replace with a new one.

When installing the new filter(s), note the direction of the airflow ar- rows on the filter frame.

If you have difficulty locating your air filter(s) or have questions concerning proper filter maintenance, contact your dealer for in- structions. When replacing filters, always use the same size and type of filter that was supplied originally by the installer.

ACCESS PANEL

FILTER ACCESS PANEL*

*For accessory filter rack.

C99094

Fig. 2 - Accessory Filter Rack Access Panel

(Optional Louvered Panels shown)

!WARNING

FIRE AND UNIT OPERATION HAZARD

Failure to follow this warning could result in personal injury, death or property damage.

Never operate your unit without filters in place. An accumulation of dust and lint on internal parts of your unit can cause loss of efficiency.

Fans and Fan Motor

Periodically check the condition of fan wheels and housings and fan-motor shaft bearings. Contact your dealer for the required annu- al maintenance.

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