ACAbbreviation for alternating current, a type of electric current in which the polarity is constantly reversing causing the electron flow to reverse.
ACCAAir Conditioning Contractors of America.
AcousticalOf or pertaining to sound.
AC or DCAbbreviation for equipment capable of operating on alternating or direct current.
ACoilA heat exchanger consisting of two diagonal coils that are joined together in a manner that looks like the letter “A”.
AFUEAnnual Fuel Utilization Efficiency. A measure of a gas furnace’s efficiency in converting fuel to energy. The higher the rating, the more efficient the unit.
AGAAbbreviation for American Gas Association, Inc.
Air ConditionerAny device that can change the temperature, humidity or general quality of the air.
Air cleanerAny device that removes undesirable particles from moving air.
Air flow VolumeThe amount of air the system circulates through your home, expressed in cubic feet per minute (cfm). Proper airflow depends on the outdoor unit, the indoor unit, the ductwork and even whether the filters are clean.
Air handlerAn air moving and/or mixing unit. Residential air handlers include a blower, a coil, an expansion device, a heater rack and a filter. Heaters for air handlers are sold as accessories. In some models heaters are factory installed.
ARIAir Conditioning & Refrigeration Institute.
ASHRAEAmerican Society of Heating, Refrigeration and Air Conditioning Engineers.
BTUBritish thermal unit. The amount of heat required to raise or lower the temperature of one pound of water one degree Fahrenheit. The heat extracted from your home by an air conditioner is measured in BTUs.
BTUhBritish thermal units per hour. 12,000 BTUh equals one ton of cooling.
BurnerA device that uses fuel to support combustion.
Burner OrificeThe opening through which gas flows to the air/gas mixing chamber of the burner.
Burner (sealed combustion)A burner that obtains all air for combustion from outside the heated space.
CapacityThe output or producing ability of cooling or heating systems. Cooling and heating capacities are referred to in British thermal units (BTUs) per hour.
CelsiusThe metric temperature scale in which water freezes at zero degrees and boils at 100 degrees, designated by the symbol “C”. To convert to Fahrenheit, multiply a Celsius temperature by 9, divide by 5 and add 32 (25 x 9 equals 225, divided by 5 equals 45, plus 32 equals 77 degrees Fahrenheit).
CFMAbbreviation for cubic feet per minute, a standard measurement of airflow. A typical system requires 400 cfm per ton of air conditioning.
ChargeAdding refrigerant to a system. This is refrigerant contained in a sealed system or in the sensing bulb to a thermostatic expansion valve.
Climatuff® CompressorThe Trane Climatuff® Compressor was the world’s first successful heat pump compressor. To this day it’s the only compressor Trane uses in its residential systems. It’s well known for its superior durability, low noise levels and high efficiency.
ComfortR™ Coil or Evaporator CoilA Trane Comfort Coil is the other, less visible half of your air conditioning system and is located inside your home in the indoor unit. It’s a tubing coil in which a volatile liquid evaporates and absorbs heat. This is where the refrigerant evaporates as it absorbs heat from the indoor air that passes over the coil. It serves as a “heat exchanger,” moving heat into your home in the winter and away from your home in the summer.
ComfortR™ Airflow SystemAn exclusive feature of a high efficiency home comfort system from Trane. This method of ramping airflow gives you greater humidity control when cooling and provides warmer air during heating start up.
CompressorThis is the heart of an air conditioning or heat pump system. It is part of the outdoor unit and pumps refrigerant to meet the cooling requirements of the system.
CondensateVapor that liquefies due to the lowering of its temperature to the saturation point.
Condenser coil (or outdoor coil)In an air conditioner, the coil dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid. In a heat pump system, the coil absorbs heat from the outdoors.
Condenser FanThe fan that circulates air over the aircooled condenser.
ContactorA switch that can repeatedly cycle, making and breaking an electrical circuit. When sufficient current flows through the Acoil built into the contactor, the resulting magnetic field causes the contacts to be pulled in or closed.
Crankcase HeaterThis is the electric resistance heater installed on compressor crankcases to boil off liquid refrigerant that may have combined with compressor oil. Many newer cooling systems do not require crankcase heaters, however heat pumps do require crankcase heaters.
CSACanadian Standards Association.
DCDirect current electricity. This type of electricity (as opposed to Alternating Current, or AC) flows in one direction only, without reversing polarity.
DamperFound in ductwork, this movable plate opens and closes to control airflow. Dampers can be used to balance airflow in a duct system. They are also used in zoning to regulate airflow to certain rooms.
DefrostTo melt frost; as in from an air conditioner or heat pump coil.
DegreedayA computation that gauges the amount of heating or cooling needed for a building. A degreeday is equal to 65 degrees Fahrenheit minus the mean outdoor temperature.
DehumidifierAn air cooler that removes moisture from the air.
DiffuserA grille over an air supply duct having vanes to distribute the discharging air in a specific pattern or direction.
DOEDepartment of Energy
Downflow FurnaceA furnace that intakes air at its top and discharges air at its bottom.
Drain PanAlso referred to as a condensate pan. This is a pan used to catch and collect condensate (in residential systems vapor is liquefied on the indoor coil, collected in the drain pan and removed through a drain line).
Dry Bulb TemperatureHeat intensity, measured by a dry bulb thermometer.
Dry Bulb ThermometerAn instrument that measures air temperature independently of humidity.
DuctworkA pipe or conduit through which air is delivered. Ducts are typically made of metal, fiberboard or a flexible material. In a home comfort system, the size and application of ductwork is critical to performance and is as important as the equipment.
DXDirect expansion. A system in which heat is transferred by the direct expansion of refrigerant.
EEREnergy Efficiency Ratio (steady state).
ENERGY STAR®Trane high efficiency systems carry the ENERGY STAR label which is the result of Trane’s partnership with the U.S. Department of Energy and Environmental Protection Agency (EPA). ENERGY STAR products are more energy efficient and help reduce our whole earth’s pollution problems. Choosing a Trane ENERGY STAR Comfort System assures homeowners of lower energy bills and improved indoor air quality for their home.
EPAEnvironmental Protection Agency.
Expansion ValveA refrigerantmetering valve with a pressure or temperature controlled orifice.
Evaporator Coil (or Indoor Coil)The other half of an air conditioning system, located inside your home in the indoor unit. This is a tubing coil in which a volatile liquid evaporates and absorbs heat. This is where the refrigerant evaporates as it absorbs heat from the indoor air that passes over the coil.
FahrenheitThe temperature scale on which water freezes at 32 degrees and boils at 212 degrees; designated by the letter F. To convert Fahrenheit to Celsius, subtract 32 from the Fahrenheit number, multiply by 5 and divide by 9 (77 32 equals 45, times 5 equals 225, divided by 9 equals 25 degrees Celsius).
FanAny device that creates air currents.
FilterAny device that removes impurities through a straining process.
FlueAny vent or passageway that carries the products of combustion from a furnace.
FurnaceThat part of the heating system in which the combustion of fossil fuel and transfer of heat occurs.
FuseA metal strip in an electrical circuit that melts and breaks the circuit when excessive current flows through it. The fuse is designed to break in order to save more expensive electrical components.
GAMAGas Appliance Manufacturers Association.
Gas Furnace Heat ExchangerLocated in the furnace, the heat exchanger transfers heat to the surrounding air, which is then pumped throughout your home.
Heat ExchangerAn area, box or coil where heat flows from the warmer to the colder fluid or surface.
Heat GainHeat added to the conditioned space by infiltration, solar radiation, occupant respiration and lighting.
Heating CoilAny coil that serves as a heat source.
Heat LossThe rate of heat transfer from a heated space to the outdoors.
Heat PumpA mechanicalcompression cycle refrigeration system that can be reversed to either heat or cool the controlled space.
Heat TransferThe movement of heat energy from one point to another. The means for such movement are conduction, convection, and radiation.
HertzIn alternating current (AC electricity), the number of cycles per second.
HSPFHeating Seasonal Performance Factor. This rating is used in measuring the heating efficiency of a heat pump. The higher the number, the more efficient the heat pump system.
HumidifierA machine that adds water vapor to the air to increase humidity.
HumidistatA humiditysensing control that cycles the humidifier on and off.
HumidityThe presence of water vapor in the air.
Humidity, AbsoluteWeight of water vapor per cubic foot of dry air, expressed as grains of moisture per cubic foot.
Humidity, RelativeThe amount of moisture in the air expressed as a percentage of the maximum amount that the air is capable of holding at a specific temperature.
HVACHeating, Ventilating and Air Conditioning.
IgnitionThe lighting of a fuel to make it burn.
Kilowatt (kW)1,000 watts.
Latent HeatA type of heat, which when added to or taken from a substance, does not change the temperature of the substance. Instead, the heat energy enables the substance to change its state.
MediaThe material in a filter that traps and holds the impurities.
NECNational Energy Council / National Electric Code.
NEMANational Electrical Manufacturing Association
OEMOriginal equipment manufacturer.
OrificeAn opening or hole; an inlet or outlet.
Package UnitA heating and cooling system contained in one outdoor unit. A package unit is typically installed beside, on the roof, or sometimes in the attic of a home.
PSIPounds per square inch.
PSIAPounds per square inch, absolute.
PSIGPounds per square inch gauge.
PVCPolyvinyl chloride; a type of plastic.
Reciprocating CompressorA compressor whose piston or pistons move back and forth in the cylinders.
RefrigerantA chemical that produces a refrigerating effect while expanding and vaporizing. Most residential air conditioning systems contain R22 refrigerant. R22 is regulated under the Montreal Protocol and in the United States by the Environmental Protection Agency. R22 is scheduled to be in production until the year 2020. It’s used in approximately 95 percent of air conditioning equipment manufactured in the U.S. today.
Refrigerant ChargeThe required amount of refrigerant in a system.
SEERSeasonal Energy Efficiency Ratio. A measure of cooling efficiency for air conditioners and heat pumps. The higher the SEER, the more energy efficient the unit. The U.S. Government’s minimum SEER rating is 10.
SelfContained SystemA refrigerating system that can be moved without disconnecting any refrigerant lines; also know as a package unit.
Sensible HeatThat heat which, when added to or taken away from a substance, causes a rise or fall in temperature.
SensorAny device that reacts to a change in the conditions being measured, permitting the condition to be controlled.
SetpointThe temperature or pressure at which a controller is set with the expectation that this will be a nominal value depending on the range of the controller.
Spine Fin™ CoilAllaluminum outdoor coil that features the patented Spine Fin™ design. It provides greater heat exchanging capabilities (meaning higher efficiencies) and is more resistant to corrosion than traditional copper/aluminum
Split SystemThe combination of an outdoor unit (air conditioner or heat pump) with an indoor unit (furnace or air handler). Split systems must be matched for optimum efficiency.
Thermostatic Expansion ValveA refrigerant metering device that maintains a constant evaporator temperature by monitoring suction vapor superheat. Also called a thermal expansion valve.
ThermostatA series of sensors and relays that monitor and control the functions of a heating and cooling system.
TonA unit of measurement used for determining cooling capacity. One ton is the equivalent of 12,000 BTUs per hour.
Twostage heating / Twostage coolingTwostage heating and cooling is considered to be more efficient, because it operates at low speed most of the time. However, on days when more heating or air conditioning is required, it switches to the next stage for maximum comfort.
UFactorThe factor representing resistance to heat flow of various building materials.
ULUnderwriters Laboratories.
Upflow FurnaceA furnace in which air is drawn in through the sides or bottom and discharged out the top.
VacuumA pressure below atmospheric pressure. A perfect vacuum is 30 inches Mercury (periodic symbol “Hg”).
Variablespeed motor(s)The fan motor inside Trane’s variablespeed air handlers is designed to vary its speed based on your home’s heating and air conditioning requirements. Working in conjunction with your thermostat, it keeps the appropriatetemperature air (e.g. warm air on cold days) circulating throughout your home, reducing temperature variances in your home. It also provides greater air circulation and filtration, better temperature distribution, humidity control, higher efficiency, and quiet performance.
VoltThe unit of measure used to describe a difference in electrical potential. Abbreviated by the symbol “v”.
VoltageThe force that pushes electrical current along wires and cables.
WattThe unit of electrical power equal to the flow of one amp at a potential difference of one volt.
Wet Bulb ThermometerA thermometer whose bulb is covered with a piece of watersoaked cloth. The lowering of temperature that results from the evaporation of water around the bulb indicates the air’s relative humidity.
Zoning SystemA method of dividing a home into different comfort zones so each zone can be independently controlled depending on use and need; an air conditioning system capable of maintaining varying conditions for various rooms or zones.
Common Repairs
Listed below are some of the more common repairs that we see
throughout the year, and the causes that lead up to the part not
working.
Electrical Components
Piping Components
.::::.
Electrical Components
The Fuses and circuit breakers in the electrical supply to your air conditioning
system have large demands. Their purpose is to prevent excessive load
on the supply circuit, which could overload the entire system.
Fuses can fail from age, a loose connection, an electrical
storm, a faulty electrical component in the unit, or from simply being
loose in their holder.
Typically, a faulty fuse will result in no operation at all or only the indoor circulating fan working. Back To Top
Relays are electrically controlled switches that turn the motors, or
other components of the system, on and off. There are a variety of
relays in any given system and the thermostat operates most of them.
The largest relay is called the contactor, and it controls the power to
the compressor.
These devices can fail when the contact surfaces stop making
contact, become stuck in the on position, or they turn on the wrong
component. Also, each time one of these switches turns on and off, the
contact surfaces pit from electrical arching, eventually causing wear
and tear. Back To Top
A Capacitor helps your air conditioning systems’ motor start from a stand
still and run efficiently. Capacitors are filled with an oil-like fluid
that acts like an insulator.
Capacitors can weaken over time decreasing the motors
efficiency. Heat can also cause them to swell, leak and fail. On
occasion, a capacitor’s circuitry will open, and will need to be
replaced. A weakening capacitor usually has no noticeable effect on
your system’s operation, however it could be causing the motor to
run warmer than normal, shortening its life expectancy. Once a
capacitor has failed, the motor will not run. Back To Top
A Defrost Control limits the amount of ice that can form on you air conditioning
system. An electric heat pump heats the home by extracting heat from
the outdoor air. To do this, the system must operate at very cold
temperatures. By operating at these temperatures, the outdoor unit can
build up ice, decreasing its ability to heat. A defrost control will
turn off the outdoor fan and place the system into a type of cooling
mode to melt the ice.
A faulty defrost control in the heating mode can prevent the
system from going into the heat mode or allow excessive ice to build
upon the unit, resulting in poor performance. A failure in the cooling
mode can prevent the outdoor fan from running, resulting in a loss of
cooling. Back To Top
A Gas Valve is found in a gas furnace. When a signal is received from
the thermostat, the gas valve controls the amount of gas needed for
heating.
A gas valve can fail from electrical or mechanical reasons.
Debris or moisture in the gas piping can cause a valve to stick in the
on or off position. A gas valve can fail at any time, but most fail
after sitting idle over the summer. Normally a gas valve failure will
result in no heat. Back To Top
A Furnace Circuit Board performs a variety of functions, from normal
operation of the furnace, to the monitoring of the furnace’s
safety circuits.
The furnace circuit board can fail for a variety of reasons.
The normal vibration of the system can weaken the solder joints in its
circuitry, causing a failure. A short, or electrical failure, of the
components connected to the module can damage the internal circuitry.
Also, if it becomes exposed to moisture or excessive dirt, the
circuitry can become damaged.
The failure of a furnace circuit board can have multiple
effects, ranging from the indoor fan not turning on in the cooling
mode, or a complete loss of heat. Back To Top
The Outdoor Fan Motor, also referred to as the Condenser Fan, draws air
through the air conditioning unit to cool it off. Often, this motor can be viewed
from the top of the outdoor unit and has a propeller type fan blade and
discharges air out of the top of the unit. Due to their location, these
motors are subject to year round weather conditions, in addition to all
of the indoor heat removed while cooling a home.
An outdoor fan can fail from wear and tear. Because they are
running every time the outdoor unit is in operation, these motors can
accumulate between one and two thousand hours of operation a year.
Also, the harsh desert conditions subject the motors to extreme heat,
weakening its electrical components.
In the early stages of failure an outdoor fan motor in the
cooling mode may work through the night and morning hours but overheat
and stop in the afternoon heat. This can result in the rest of
the system overheating and stopping for several hours. Once the motor
fails completely, the unit will no longer function. Continued running
with a faulty outdoor fan motor can stress the system and eventually
cause a compressor failure, and a much more costly repair. Back To Top
The Indoor Fan Motor, or Blower Motor, circulates the air from the home
through the heating and cooling system. These motors run constantly
when the unit is heating or cooling, but can also be set to run even
when the air conditioning unit is off.
An indoor fan motor can fail from normal wear and tear, or
from electrical problems. If dust collects in the motor, it can cause
hot spots on the electrical windings and damage them. If dust forms on
the fan wheel, it may cause the wheel to spin out of balance. The more
out of balance a blower wheel is, the more stress it places on the
motor bearings.
Early signs of motor failure due to the bearings will be
increased operating sound. Total failure of the motor will result
in no heating or cooling. The system may try and work, but it will not
be able to circulate air from the home. If left to run in this state
for too long, other heating and cooling components can be strained or
compromised. Back To Top
The Compressor acts as a pump to circulate refrigerant through the air conditioning
system. It resides in the outdoor unit, and like the engine of a
car, has an audible sound when in use.
Compressors can fail for a variety of reasons, including the
motor bearings simply wearing out. Most times, a compressor will be
strained by the failure of another component, such as a fan motor or
the capacitor. Electrical storms can cause problems for a compressor,
and almost always produce a noticeable increase in compressor
replacements. Early signs of compressor failure may be a decrease in
performance or an increase in operating sound. Total failure will
result in no cooling, or no heating from a heat pump. Back To Top
Piping Components
The Refrigerant Metering Device controls the flow of refrigerant
through the air conditioning system much like a traffic light controls the flow of
traffic down a street. All air conditioning systems will have at least
one refrigerant metering device, and heat pumps will have two.
Much of a system’s efficiency is derived from the proper
operation of this device. Too little refrigerant flow will cause the
system to have reduced performance, and could cause the compressor to
overheat. Too much refrigerant circulating though the system could
overwhelm the compressor, causing damage. Often, a total failure of
this component will result in the system not cooling or heating at all.
Reversing Valves are only found on electric heat pumps and are used to
reverse the flow of refrigerant from the cooling mode to the heating
mode and back again. They reside in the outdoor unit, and all of the
system’s refrigerant flows through them.
The failure of a reversing valve can cause the system to stick
in the heating or cooling mode. At times, the valve may fail in an
intermediate position resulting in the system not working.
Any debris in the system can cause the reversing valve to
fail. Also, normal wear of other components in the refrigerant system,
or the failure of a compressor or other device, can cause the reversing
valve to fail. Back To Top
A Restriction, or blockage, in the refrigerant system of a air conditioning unit
can come in varying degrees. Screens, strainers or filters in the
refrigerant system are installed in an effort to trap debris and
prevent the failure of various components. However, large amounts of
debris can result in a restriction, reducing the refrigerant flow
through the system. A slight restriction may result in decreased
performance. A larger restriction can result in the system not cooling
or heating at all. Back To Top
An Indoor Coil is a heat transfer device. The indoor coil absorbs the
heat from the home’s indoor air, and passes it to the
system’s refrigerant, which is then pumped outside.
As the air passes across the coil, any airborne dust or lint
that collects on the coil reduces its ability to perform. Also, to
provide the highest level of heat transfer, the metal used is extremely
thin. Airborne chemicals, detergents and cleaners can start corrosion,
resulting in leaks.
A coil in need of cleaning may have lower performance, or can
ice up from the low airflow. A leaking indoor coil may operate for
weeks, or even months, depending on the leak rate, but should be
repaired or replaced to prevent further, more costly, damage. Leaks can
occur in such locations that an attempted repair is not practical, and
the entire unit may need to be replaced. Back To Top
An Outdoor Coil is a heat transfer device. The outdoor coil draws the
outdoor air across the coil to absorb the heat from the
refrigerant.
An outdoor coil should be cleaned periodically. Any dirt and
dust in the air can be trapped on the coil and restrict its airflow and
reduce its performance. They can also develop leaks from the constant
vibration of the compressor, weakening the solder joints and tubing.
The refrigerant is under very high pressures in the outdoor coil and
even the smallest leak can result in a complete loss of the refrigerant
charge. Any dirt and debris in the coil can increase these pressures
straining the coil’s integrity. Back To Top
Drain Lines allow your air conditioning system to drain off the water it has
condensed from the air. Over time the drain line can become blocked and
cause the drain pan in the unit to overflow. Dust and dirt from the
indoor coil can be washed into the drain line, where it settles and
causes blockage. Unlike the failure of most other items in the system,
a drain line failure can result in expensive water damage repairs.
Drain lines rarely give warning prior to becoming blocked and should be cleared annually. Back To Top
