Air conditioner & heat pump types, components, & parts descriptions.

This article describes the different types of air conditioning or heat pump systems and names the parts & components of those systems. This information provides a guide for the inspection, diagnosis or repair of air conditioners and heat pumps.

This article series describes how to inspect and repair all types of residential air conditioning systems (A/C systems). Information for home buyers, owners, and home inspectors about A/C or heat pump system problems.

Page top image provided courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ]. A somewhat simpler schematic of an air conditioning-only system is provided just below.
Srpski prevod nad današji stranica [Serbian translation of air conditioning diagnosis and repair articles]

Air Conditioning & Heat Pump Components List - An Inspection Guide

Conventional Residential Air Conditioner Components: Outside Condenser/Compressor unit, Inside Evaporator Air Handler unit

Conventional A/C cooling or Heat Pump systems include the following components:

Indoor Components of an air conditioning system

Here we give an organized list of InspectApedia.com pages that explain each of the major components of air conditioners and heat pumps.

Details about sub-components of A/C and heat pump systems can be read and seen

at AIR CONDITIONER COMPONENT PARTS

1. Air Handler Unit (AHU) which typically includes the following
   
   AIR HANDLER / BLOWER UNITS
• Air filters - located at return registers or possibly at or in the air handler
  
  AIR FILTERS for HVAC SYSTEMS
• Return Plenum
• Blower fan in a blower compartment
  
  BLOWER FAN OPERATION & TESTING
• Evaporator Coil = Cooling Coil
  
  COOLING COIL or EVAPORATOR COIL
• Supply plenum
• Condensate collection & drainage system
  
  CONDENSATE HANDLING, HVAC
2. Supply air ducts and registers [
   
   DUCT SYSTEM DESIGN SIZE & DEFECTS
3. Return air ducts and registers (see the article link just above)
4. Electrical shut off switches, circuit breakers/fuses
   
   CONTROLS & SWITCHES, A/C - HEAT PUMP

Outdoor Air Conditioning System Components

Details can be read and seen at AIR CONDITIONER COMPONENT PARTS

1. Compressor motor - on residential units this is normally a hermetic motor-compressor combined in a single sealed unit - that compresses low pressure refrigerant gas back to a high pressure gas that is then condensed to liquid refrigerant
   
   COMPRESSOR / CONDENSER REPAIR
2. Condensing coil - condenses the high pressure refrigerant gas back to a liquid
   
   CONDENSING COIL REPAIR REPLACE
3. Outdoor cooling fan or condenser unit fan - moves air across the condensing coil, transferring heat from the coil into nearby air (in cooling mode) or for a heat pump in heating mode, transfers heat from the air into the refigeraint
   
   FAN, COMPRESSOR / CONDENSER UNIT
4. Electrical shut-off switch(es) for service & circuit protection -
   
   CONTROLS & SWITCHES, A/C - HEAT PUMP

All of the components, controls, switches of air conditioning systems and how to diagnose and debug cooling system problems are discussed in detail at this website.

Rooftop Air Conditioning System Components

Rooftop combined units: While the list above describes the common components of a typical residential air conditioning system, other configurations and packaged units are also in increased use in both residential and commercial installations.

Alternative air conditioning system designs may combine all components except for the duct work in a rooftop mounted unit such as the one shown above where it was mounted on a flat roof over offices at a commercial building.

More details:

see ROOFTOP HVAC UNITS

Wall Convector Heating and Air Conditioning Units

Wall convector heating and cooling units (at left) are often used for both heating and cooling in commercial installations and high-rise apartment buildings. The unit shown has its own compressor mounted right in the cabinet, visible at lower center in the photo.

Wall-mounted heating and cooling convector installations may be designed with one central heater or cooling system which feeds multiple units with chilled or heated water or possibly refrigerant from a single remote heating and cooling heat pump.

Details about wall convectors used for heating or cooling and about convector blower fans are found

at WALL CONVECTORS HVAC and also

at FAN COIL & FAN CONVECTOR HEATERS & HYDRONIC COILS

Split System Air Conditioners or Ductless Air Conditioners & Heat Pumps

Another common residential alternative dispenses with duct work entirely, using a wall-mounted indoor evaporator/blower unit and a separate outside compressor/condenser (below left and right). In this split system air conditioning design, one compressor/condenser may serve multiple wall-mount indoor units.

The Sanyo® compressor/condenser unit shown (above left) can support two indoor evaporator/fan cooling units. In this installation the indoor units were mounted in two different areas of the home.

The thermostat and controls for split system air conditioners and heat pumps may be wall mounted but often are a portable hand-held remote controller.

Details about ductless air conditioners, split systems, mini split systems and ceiling-mount A/C systems are

at SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS.

Goofy Home Made or Do-it-yourself Air Conditioning Systems

Do-It-Yourself Home made air conditioning systems such as this goofy example may actually work but not without problems. This system used a window air conditioner placed in a home's attic.

Manhole ventilation duct (liberated from New York City) was used along with a home made hood attached to the air conditioner to blow cool air into the home through a ceiling register.

The air conditioning condensate was collected in the blue plastic kiddie pool seen in the photo, and drained by gravity to a plumbing vent stack.

Nothing about the system was proper, safe, nor very effective, and in addition, the attic moisture conditions were terrible as you can see from the blackened plywood roof sheathing.

Also see: HOME MADE AIR CONDITIONER SYSTEMS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-06-09 - by (mod) -

In the ARTICLE INDEX you'll see that we have articles on electric motor repair starting

at ELECTRIC MOTOR DIAGNOSTIC GUIDE - home

Sometimes a service technician will measure the current draw of the motor and compare that with the specification to look for an indication that the motor is a drawing excessive current and therefore perhaps has a feeling bearing

Also see ELECTRIC MOTOR NOISE DIAGNOSIS

On 2020-06-09 by Motor sounds labored

I have a wall mounted air conditioner (several decades old -Sears Coldspot Model 10667610) and the motor moves but slowly. The air that comes out is cool but I turned it off before I could determine if it was going to become cold. Both low and high speeds are the same. I thought it might be the running cap (25uf, 440vac), so I changed it - to no benefit.

The sound is not of a stalled motor but something in that direction. (I want to replace it with a FFRE253WAE but I am unable to get technical info on that unit. My present old unit sits within a sleeve and I would like to know what the dimensions of the unit are without the shell.)

So, if the motor sounds labored and runs slowly but the unit cools, what would be a first good place to look?

On 2016-11-18 by david

heat pump not engaging air handler fan runs continuously with multiple limit openings

On 2014-07-30 - by (mod) -

Phil,

Sounds like a failed compressor motor. I'd leave the system off while waiting for repair.

On 2014-07-25 by Phil

Heat pump compressor shut down and fan motor was very hot.Need help.

On 2014-06-30 - by (mod) -

Patricia, not necessarily, but it may depend on just what happened.mfor example a short circuit might damage not just the fan but it's control panel circuit board or relay.

On 2014-06-29 by Patricia

Does operating board/panel need to be replaced if only air fan breaks ?

On 2014-06-06 by brewer

I have a 23 year old carrier out door unit, the compressor just went out, should I repair or replace it ?

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Continue reading at AIR CONDITIONING & HEAT PUMP SYSTEMS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• AIR CONDITIONING & HEAT PUMP SYSTEMS
• SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS

Suggested citation for this web page

PARTS - AIR CONDITIONING or HEAT PUMP at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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