WeatherMaster® High-Efficiency Single-Packaged Rooftop Units 48HC: Quarterly Maintenance

Air Conditioning

Ensure outdoor fan motor mounting bolts are tight
Ensure compressor mounting bolts are tight
Inspect outdoor fan blade positioning
Ensure control box is clean
Check control box wiring condition
Ensure wire terminals are tight
Check refrigerant charge level
Ensure indoor coils are clean
Check supply blower motor amperage

Heating

Heat exchanger flue passageways cleanliness
Gas burner condition
Gas manifold pressure
Heating temperature rise

Economizer or Outside Air Damper

Check inlet filters condition
Check damper travel (economizer)
Check gear and dampers for debris and dirt

Air Filters and Screens

Each unit is equipped with return air filters. If the unit has an economizer, it will also have an outside air screen. If a manual outside air damper is added, an inlet air screen will also be present.

Each of these filters and screens will need to be periodically replaced or cleaned.

Filters

RETURN AIR FILTERS

! CAUTION

EQUIPMENT DAMAGE HAZARD

Failure to follow this CAUTION can result in premature wear and damage to equipment.

DO NOT OPERATE THE UNIT WITHOUT THE RETURN AIR FILTERS IN PLACE.

Dirt and debris can collect on heat exchangers and coils possibly resulting in a small fire. Dirt buildup on components can cause excessive current used resulting in motor failure.

Return air filters are disposable fiberglass media type. Access to the filters is through the small lift-out panel located on the rear side of the unit, above the evaporator/return air access panel. (See Fig. 3.)

FIG. 3

To remove the filters:

Grasp the bottom flange of the upper panel.
Lift up and swing the bottom out until the panel disengages and pulls out.
Reach inside and extract the filters from the filter rack.
Replace these filters as required with similar replacement filters of same size.

To re-install the access panel:

Slide the top of the panel up under the unit top panel.
Slide the bottom into the side channels.
Push the bottom flange down until it contacts the top of the lower panel (or economizer top).

OUTSIDE AIR HOOD

Outside air hood inlet screens are permanent aluminum-mesh type filters. Check these for cleanliness. Remove the screens when cleaning is required. Clean by washing with hot lowpressure water and soft detergent and replace all screens before restarting the unit. Observe the flow direction arrows on the side of each filter frame.

ECONOMIZER INLET AIR SCREEN

This air screen is retained by filter clips under the top edge of the hood. (See Fig. 3.) FIG. 3

To remove the filter, open the filter clips. Re-install the filter by placing the frame in its track, then closing the filter clips.

MANUAL OUTSIDE AIR HOOD SCREEN

To remove the screen, loosen the screws in the top retainer and slip the retainer up until the filter can be removed. Re-install by placing the frame in its track, rotating the retainer back down, and tightening all screws.

SEASONAL MAINTENANCE

These items should be checked at the beginning of each season (or more often if local conditions and usage patterns dictate):

Air Conditioning

Ensure outdoor fan motor mounting bolts are tight

Ensure compressor mounting bolts are tight

Inspect outdoor fan blade positioning

Ensure control box is clean

Check control box wiring condition

Ensure wire terminals are tight

Check refrigerant charge level

Ensure indoor coils are clean

Check supply blower motor amperage

Heating

Heat exchanger flue passageways cleanliness

Gas burner condition

Gas manifold pressure

Heating temperature rise

Economizer or Outside Air Damper

Check inlet filters condition

Check damper travel (economizer)

Check gear and dampers for debris and dirt

Air Filters and Screens

Each unit is equipped with return air filters. If the unit has an economizer, it will also have an outside air screen. If a manual outside air damper is added, an inlet air screen will also be present.

Each of these filters and screens will need to be periodically replaced or cleaned.

Filters

RETURN AIR FILTERS

! CAUTION

EQUIPMENT DAMAGE HAZARD

Failure to follow this CAUTION can result in premature wear and damage to equipment.

DO NOT OPERATE THE UNIT WITHOUT THE RETURN AIR FILTERS IN PLACE.

Dirt and debris can collect on heat exchangers and coils possibly resulting in a small fire. Dirt buildup on components can cause excessive current used resulting in motor failure.

Return air filters are disposable fiberglass media type. Access to the filters is through the small lift-out panel located on the rear side of the unit, above the evaporator/return air access panel. (See Fig. 3.)

FIG. 3

To remove the filters:

Grasp the bottom flange of the upper panel.

Lift up and swing the bottom out until the panel disengages and pulls out.

Reach inside and extract the filters from the filter rack.

Replace these filters as required with similar replacement filters of same size.

To re-install the access panel:

Slide the top of the panel up under the unit top panel.

Slide the bottom into the side channels.

Push the bottom flange down until it contacts the top of the lower panel (or economizer top).

OUTSIDE AIR HOOD

ECONOMIZER INLET AIR SCREEN

This air screen is retained by filter clips under the top edge of the hood. (See Fig. 3.) FIG. 3

To remove the filter, open the filter clips. Re-install the filter by placing the frame in its track, then closing the filter clips.

MANUAL OUTSIDE AIR HOOD SCREEN

To remove the screen, loosen the screws in the top retainer and slip the retainer up until the filter can be removed. Re-install by placing the frame in its track, rotating the retainer back down, and tightening all screws.

SUPPLY FAN (BLOWER) SECTION

! WARNING

ELECTRICAL SHOCK HAZARD

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

Before performing service or maintenance operations on unit, LOCKOUT/TAG-OUT the main power switch to unit. Electrical shock and rotating equipment could cause severe injury.

Supply Fan (Direct-Drive)

All FC units have the EcoBlue™ direct drive vane axial fan system. The fan is driven by an ECM motor with speed that is user set through the Unit Control Board (UCB). Speeds are fully configurable from 40% to 100% of motor’s maximum speed. See Fig. 5 and 6.

FIG. 6