Checking Cooling and Heating Control Opera

Should room temperature continue to fall, circuit R-W is made through second-stage thermostat bulb. If optional elec- tric heat package is used, a relay is energized, bringing on supplemental electric heat. When thermostat is satisﬁed, con- tacts open, deenergizing contactor and relay; motors and heat- ers deenergize.

DEFROST — Defrost board (DB) is a time and temperature control, which includes a ﬁeld-selectable time period be- tween checks for frost (30, 50, and 90 minutes). Electronic timer and defrost cycle start only when contactor is ener- gized and defrost thermostat (DFT) is closed (below 28 F [−2.2 C]).

Defrost mode is identical to Cooling mode, except outdoor- fan motor (OFM) stops and a bank of supplemental electric heat turns on to warm air supplying the conditioned space. Defrost mode is terminated when the DFT reaches 65 F (18.3 C).

Checking Cooling and Heating Control Opera-

tion — Start and check the unit for proper control opera- tion as follows:

1.Place room thermostat SYSTEM switch in an OFF po- sition. Observe that blower motor starts when FAN switch is placed in ON position and shuts down when FAN switch is placed in AUTO. position.

2.Place SYSTEM switch in COOL position and FAN switch in AUTO. position. Set control below room temperature. Observe that compressor, outdoor fan, and indoor fan mo- tors start. Observe that cooling cycle shuts down when control setting is satisﬁed.

3.Place system switch in HEAT position. Set control above room temperature. Observe that compressor, outdoor fan, indoor fan motor, and electric heaters (if equipped) start. Observe that heating cycle shuts down when control set- ting is satisﬁed.

4.When using an automatic changeover room thermostat, place both SYSTEM and FAN switches in AUTO posi- tions. Observe that unit operates in Cooling mode when temperature control is set to ‘‘call for Cooling’’ (below room temperature), and unit operates in Heating mode when temperature control is set to ‘‘call for heating’’ (above room temperature).

Malfunction — The high-pressure switch, loss-of- charge switch, and compressor overtemperature safety are located in a Cycle-LOC™ circuit that prevents heat pump operation if these safety devices are activated.

The lockout system can be reset by adjusting the thermo- stat to open the contacts (down for heating mode, up for cool- ing mode) deenergizing the Cycle-LOC circuitry. Compres- sor overcurrent protection is achieved with overload breakers which are temperature sensitive and will automatically reset.

Unit is equipped with a no-dump reversing valve circuit. When unit is in cooling mode, reversing valve remains in cooling position until a call for heating is requested by ther- mostat. When unit is in heating mode, reversing valve re- mains in heating position until there is a call for cooling.

SERVICE

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

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

OUTDOOR COIL — Inspect coil monthly. Clean outdoor coil annually and as required by location or outdoor-air conditions.

Clean coil as follows:

1.Turn off unit power.

2.Remove and save top panel screws on outdoor unit.

3.Remove outdoor coil corner post. See Fig. 12. To hold top panel open, place coil corner post between top panel and side panel. See Fig. 13.

4.Remove bracket holding coil sections together at return end of outdoor coil. Carefully separate the outer coil sec- tion 3 to 4 in. from the inner coil section. See Fig. 14.

5.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.

6.Reposition the outer coil section and secure the sections together. Remove the coil corner post from between the top panel and side panel. Install the coil corner post and replace all screws removed in Step 2.

Lubrication

COMPRESSORS — Compressor has its own oil supply. Loss of oil due to a leak in the system should be the only reason for adding oil after the system has been in operation. See Start-Up, Oil Charge section.

FAN MOTOR BEARINGS — Fan motor bearings are of the permanently lubricated type. No further lubrication is required.

Outdoor-Fan Adjustment (Fig. 15)

1.Shut off unit power supply.

2.Remove outdoor-fan assembly (grille, motor, motor cover, and fan).

3.Loosen fan hub setscrews.

4.Adjust fan height as shown in Fig. 15.

5.Tighten setscrews.

6.Replace outdoor-fan assembly.

Compressor Removal — See Tables 1A and 1B for compressor information. Follow safety codes and wear safety glasses and work gloves.

1.Shut off power to unit. Remove unit access panel (front of unit).

2.Remove refrigerant from system using refrigerant re- moval methods described in Carrier’s Refrigrant Serv- ice Techniques manual.

3.Disconnect compressor wiring at compressor terminal box. Disconnect high-pressure switch.

4.Remove bolts from discharge service valve and suction ﬂange.

Excessive movement of copper lines at compressor may cause higher levels of vibration when unit is restored to service.

38AQS008 specifications

The Carrier 38AQS008 is a high-performance air conditioning unit that stands out for its innovative technology, design, and efficiency. As part of Carrier's extensive line of HVAC solutions, this model is engineered to deliver optimal indoor comfort while minimizing energy consumption.

One of the main features of the Carrier 38AQS008 is its high SEER rating, which signifies exceptional energy efficiency. This rating ensures that consumers can enjoy lower utility bills and reduced environmental impact, making it an ideal choice for eco-conscious homeowners. The unit's advanced cooling technologies work seamlessly to maintain precise temperature control, ensuring a pleasant environment regardless of the season.

The Carrier 38AQS008 employs a variable-speed compressor, which allows the system to adjust its operation based on the cooling demand. Unlike traditional fixed-speed units that operate at a single speed, the variable-speed technology leads to quieter operation, increased efficiency, and improved dehumidification. As the unit operates at lower speeds, it can effectively reduce energy usage when full cooling capacity is not required, further enhancing overall efficiency.

In addition to its potent cooling capabilities, the Carrier 38AQS008 incorporates a robust filtration system that captures airborne particles, dust, and allergens. This feature not only improves indoor air quality but also ensures that the system operates efficiently by maintaining clean coils. Users can enjoy a healthier living space while also prolonging the lifespan of the air conditioning unit.

Another characteristic of the Carrier 38AQS008 is its durable construction, designed to withstand harsh weather conditions. The unit is equipped with a galvanized steel cabinet that offers corrosion resistance, and its compact design allows for easy installation and integration into various home environments.

Moreover, the Carrier 38AQS008 is compatible with smart home technology, allowing users to control their air conditioning system remotely. This feature enhances convenience and efficiency, as homeowners can adjust settings based on their daily routines and preferences.

Meeting rigorous energy performance standards, the Carrier 38AQS008 exemplifies Carrier's commitment to sustainability and customer satisfaction. With its combination of advanced features, reliable performance, and user-friendly technology, this air conditioning unit is a superior choice for those seeking a dependable and efficient cooling solution.