Air Handler Terminology HVACR416 - Design Air Handler Terminology

Basic System Components Condenser Condenser Coils Compressor Condenser Fan

Basic System Components Condenser Coil Can be shaped: Horseshoe Round Flat / Straight Can be folded over in more than one layer The coil is a fin and tube design Aluminum fins / copper tube Aluminum fins / aluminum tubes

Basic System Components Condenser Fan A propeller type fan blade that pulls air through the condenser coil. Air is NEVER pushed through the coil. If you ever see that check rotation of the fan.

Basic System Components Compressor Heart of the refrigeration cycle. Gives off quite a bit of heat and is sometimes the noisiest component of the cycle.

Basic System Components Air Handler Blower section of the system Used for circulating the conditioned air Always present in A/C and heat pumps Consists of: Evaporator Coil Metering Device Blower

Basic System Components Evaporator Coil Inside Air Handler Can be shaped: “A” Shaped Coil Flat Coil Slant Coil “H” Coil “W” Coil

Basic System Components Metering Device Capillary Tube Fixed Orifice TXV (Thermostatic Expansion Valve)

Basic System Components Blower Normally a squirrel cage type blower wheel Direct Drive Belt Drive Usually a PSC, ECM, or Shaded Pole motor

Basic System Electrical Air Handler Indoor Fan Contactor 24 volt relay controls line voltage blower motor Terminal Strip Junction point for all of the wiring Good practice is to use crimp connectors and forks for all connections to terminal strip.

Basic System Electrical Air Handler Integrated Control Board The brains of the system Monitors the operation of the indoor fan motor Has timers and relays built into the control to start and stop the motor. Controls the speed of an ECM motor.

Basic System Electrical Air Handler Low voltage transformer Takes line voltage and steps it down to a lower voltage (24VAC) Low voltage is called the “Control Voltage” Line voltage is usually 240/208 or 120 Volts

Basic System Electrical Condenser Uses a relay coil to energize a compressor and fan. Control voltage usually 24 volts Sometimes has a delay timer Sometimes uses a start capacitor Always has a run capacitor Uses a high pressure switch in case of unsafe refrigerant pressures.

Basic System Electrical Condenser Includes a low pressure switch in case of refrigerant loss. Has a fan motor - usually a PSC type.

Basic System Electrical Low Pressure Switch Low pressure switch will open in a drop of pressure. Can be caused by: Dirty Evaporator Coil Restricted evaporator air flow Faulty evaporator fan motor Low ambient temperatures

Basic System Electrical High Pressure Switch Opens on a rise in pressure Usually around 300psi on R22 systems Usually around 600-700psi on R410A Caused by: Dirty condenser coil Restricted condenser air flow Faulty condenser fan Extremely high ambient temperatures

Basic System Mechanical Air Handler Evaporator has connections for the installation of copper tubing, or line sets. Liquid line Liquid refrigerants travel through this line Typical sizes are 1/4”, 5/16”, 3/8” and 1/2” Suction line The suction line is the larger diameter tubing Should always be fully insulated Vapor refrigerant travels in this line Typical sizes are 5/8”, 3/4”, 7/8” and 11/8”

Basic System Mechanical Air Handler Has condensate drain connections Typically a 3/4” female PVC connection If no drain is present: A condensate removal pump must be installed to pump to a drain (sink, washer, etc) Many installations will allow the tubing to drain outdoors (watch for freezing). Attic installs allow pvc to drain into the gutter system or down the side of the house.

Basic System Mechanical Condenser Connection for the other end of the line sets. Liquid line should always have a filter drier on it. Filter is directional, liquid runs away from the condenser. Heat pumps must have bi-directional filter drier.

Basic System Mechanical Condenser Usually installed outdoors Must be installed level Must be free of surrounding shrubs and any item that will restrict air flow.

Four basic common A/C systems System Types Four basic common A/C systems Split System Packaged System Ductless Systems Window Units

Split Systems The evaporator and the condenser are separate pieces of equipment. The evaporator section Installed in attic, basement or closet May be a part of the air handler May be installed on a furnace Has its own electrical power disconnect Has its own circuit breaker

Split Systems

Air Handler Section Split Systems Contains the blower Used for circulating conditioned air Air conditioning and heat pumps use the air handler.

Air Handler Split Systems Consist of: Evaporator Coil is a fin and tube design. Metering device Blower

Condenser Section Split System Consists of: Fan motor Condenser coil Outside on a level pad Own power source Has its own circuit breaker Must have a disconnect within arms reach of the unit Consists of: Fan motor Condenser coil Compressor Controls

Packaged Unit Located outdoors Usually commercial but sometimes seen in residential for mobile homes. Mostly over 5 ton capacity in commercial. All major components are located inside one unit.

Packaged Unit

Package Unit Major components Evaporator Condenser Compressor Condenser Fans Evaporator Fan (indoor blower) Must have own circuit breaker Must have disconnect within arms reach of unit

Package Unit Must have 120V outlet (GFCI) within arms length of unit. Units are single or multi-stage. Multistage allows for additional heating and cooling load control. Stage 1 is for light duty conditions Stage 2 is for more than a 2 degree difference between room temp and thermostat set point.

Package Units Package units are mounted on a concrete slab or on a roof. If on roof there is a roof curb and a plenum under it. If mounted on slab the supply and return air ducts are on the side of the unit. All ductwork must be insulated.

Ductless Systems Ductless systems contain the evaporator, condenser condenser pad, and line set without any ductwork. Can be a single piece or a split system. Can be ordered with low ambient controls. Very quiet and a quick install.

Ductless systems Extremely efficient units, cool the space the evaporator is mounted in. No thermostat is needed, uses a remote control or control set on the evaporator itself. Tonnage available varies. Sometimes allows more than 1 evaporator for a condenser.

Ductless systems

Window Units Smaller packaged units to put in a wall or window to comfort cool an individual room or space. Very low cost to purchase. May cost more to service and or repair than the originial purchase price. Service Fee + Hourly Rate + Parts = $$$$$$ Known mostly as throw away units.