Carrier 48TF004-007 specifications Service

HEATING, UNITS WITH ECONOMIZER — When the thermostat calls for heating, terminal W1 is energized. To pre- vent thermostat short-cycling, the unit is locked into the Heat- ing mode for at least 1 minute when W1 is energized. The induced-draft motor is energized and the burner ignition se- quence begins. The indoor (evaporator) fan motor (IFM) is en- ergized 45 seconds after a flame is ignited and the damper moves to the minimum position. On units equipped for two stages of heat, when additional heat is needed, W2 energized and the high-fire solenoid on the main gas valve (MGV) is en- ergized. When the thermostat is satisfied and W1 is deener- gized, the IFM stops after a 45-second time-off delay. The economizer damper then moves to the fully closed position. When using continuous fan, the damper will remain in the min- imum position.

SERVICE

When servicing unit, shut off all electrical power to unit and install lockout tag to avoid shock hazard or injury from rotating parts.

Cleaning — Inspect unit interior at the beginning of heating and cooling season and as operating conditions require.

EVAPORATOR COIL

1.Turn unit power off and install lockout tag. Remove evaporator coil access panel.

2.If economizer or two-position damper is installed, re- move economizer by disconnecting Molex plug and re- moving mounting screws. Refer to accessory economizer installation instructions or Optional Economizer sections on pages 12 and 14 for more details.

3.Slide filters out of unit.

4.Clean coil using a commercial coil cleaner or dishwasher detergent in a pressurized spray canister. Wash both sides of coil and flush with clean water. For best results, back- flush toward return-air section to remove foreign materi- al. Flush condensate pan after completion.

5.Reinstall economizer and filters.

6.Reconnect wiring.

7.Replace access panels.

CONDENSER COIL — Inspect coil monthly. Clean con- denser coil annually, and as required by location and outdoor air conditions.

One-Row Coils (Size 004) — Wash coil with commercial coil cleaner. It is not necessary to remove top panel.

2-Row Coils (Sizes 005-007)

Clean coil as follows:

1.Turn off unit power and install lockout tag.

2.Remove top panel screws on condenser end of unit.

3.Remove condenser coil corner post. See Fig. 42. To hold top panel open, place coil corner post between top panel and center post. See Fig. 43.

4.Remove screws securing coil to compressor plate and compressor access panel.

5.Remove fastener holding coil sections together at return end of condenser coil. Carefully separate the outer coil section 3 to 4 in. from the inner coil section. See Fig. 44.

6.Use a water hose or other suitable equipment to flush down between the 2 coil sections to remove dirt and debris. Clean the outer surfaces with a stiff brush in the normal manner.

7.Secure inner and outer coil rows together with a field- supplied fastener.

8.Reposition the outer coil section and remove the coil cor- ner post from between the top panel and center post. Re- install the coil corner post and replace all screws.

CONDENSATE DRAIN — Check and clean each year at start of cooling season. In winter, keep drain dry or protect against freeze-up.

FILTERS — Clean or replace at start of each heating and cool- ing season, or more often if operating conditions require it. Re- placement filters must be same dimensions as original filters.

OUTDOOR-AIR INLET SCREEN — Clean screen with steam or hot water and a mild detergent. Do not use disposable filters in place of screen.

BELTS — Check belt tension at least once each heating or cooling season or as conditions require.

Fig. 42 — Cleaning Condenser Coil

Fig. 43 — Propping Up Top Panel

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