Guide to Understanding AC & Heating

AC by J’s Guide to Understanding AC & Heating

Parts and repair research can be done with our guide to understanding heating and AC in Phoenix, AZ If you need service, please call (602) 266-3678. This guide gives basic information regarding the parts in your AC and heating system.


…an air conditioner start device

gtu-capacitors-300x227Causes of failure:

  • Internal short or open circuit
  • Weak capacity (caused by shorted plates)
  • Leaking or bulged housing
  • A hard starting compressor
  • A short cycling compressor

Did you know? When a Run Capacitor fails, it is wise to consider a Compressor Hard Start Kit to avoid Secondary system failure.

Weak Capacitor Chart:

Replace Capacitor not within the following listed range:
60UF 63.8/58.4 30UF 31.8/28.2 7.5UF 7.9517.05
55UF 58.3/51.7 20UF 21.2/18.8 5UF 5.3/4.70
45UF 47.7/42.3 15UF 15.9/14.1 3UF 3.18/2.82
35UF 37.1132.9 10UF 10.6/9.40

Ask the experts:  A bad or weak Run Capacitor can significantly shorten the life of your air conditioner.

Contactors & Relays

…a Contactor is the main switch that supplies power to your Compressor

contactorCauses of failure:

  • Pitted or corroded contact points
  • Short Cycling
  • lnsect(s) shorted out contact points
  • Contacts stuck open or closed
  • Burned wiring
  • Burned out or shorted coil

Did you know?  The major killer of compressors is a contactor with pitted or corroded contact points.  Ask the experts:  Replacing a Contactor older than 5 years will extend the life of your air conditioner.

Compressor Hard Start Kit

…reduces starting AMPS

gtu-compressor-hard-start-300x223Causes of failure:

  • Relay Contact stuck or burnt
  • Compressor drawing extreme amps at start up
  • Voltage drop (bad contractor points)

Did you know?  Reducing amps at start up will prolong the life of your system.  Ask the experts:  If a compressor starts to draw high amps at start up, it is a sign that it is “seizing up” & at risk for potential failure.

Motors & Blowers

…circulates the household air

Dirty Blower

Clean Blower

Causes of failure:

  • Shorted or open motor windings
  • Seized motor bearings
  • System age
  • Out of balance or broken fan blade
  • Short cycling
  • Defective capacitor

Did you know? If the Condenser Fan/Blower has failed and the unit is 8 to 10 years old or older, you should consider system replacement. Ask the experts: Condenser Fan/Blower failure is a good indication that the air conditioner is old and more trouble is on the way. A complete system replacement is highly recommended.

Causes of failure:

  • Motor electrical failure
  • Worn or seized motor bearings
    • Noisy Blower
    • Blower running below normal speed
  • Wheel defective or out of balance
  • Dirty blower motor or wheel

Did you know? Quality contractors will replace both the Blower Wheel and the Blower Motor when the Blower Motor needs replacing. This can limit annoying blower noise and prevent premature failure of the replacement motor bearings. Ask the experts: Often the Blower Wheel is severely damaged when trying to remove it from a rusted motor shaft.

Dirty Condenser Coil

…prevents efficient heat transfer

gtu-dirty-condensor-coil-1Dirty Condenser Coil:

  • Air conditioners or heat pump condenser coils can get plugged up by dust, dirt, pollen, grass, and other foreign debris.  (Sometimes these things are not seen by just looking at the condenser)

Problems caused by this condition:

  • Unit loses the ability to remove heat from the system
  • Results in higher pressures in the condenser which causes the compressor to pull amps
  • Higher amp draw means higher electric bills
  • Lack of air flow through the condenser causes the condenser fan motor to run hotter than normal and the Compressor to run hotter because of the higher load conditions


  • Premature failure of compressor and/or condenser fan motor
  • Higher than normal electric bills.

Comfort Club Membership

Part of our Comfort Club Membership is to clean condenser coils every visit, to ensure maximum efficiency.

Dirty Filter or Evaporator Coil

….reduces efficiency & shortens system life

coilDirty Filter or Evaporator Coil:

  • Dirty filter or evaporator coil causes the air side of the equipment (the part that delivers conditioned air in the dwelling) to lose the ability to deliver the proper amount of air inside the home
  • Diminished air flow capacity causes the evaporator coil to starve for air. All Evaporator Coils are designed for a specific volume of air passing over them. If the specific volume of air is not attained through normal operation there is not enough heat transfer from the air to the coil. This can leave some of the refrigerant in a liquid state
  • Problems with not evaporating all of the refrigerant in the coil is that the liquid refrigerant can be harmful to a compressor
  • Liquid doesn’t compress so the compressor, which is designed to compress, may fail mechanically if liquid makes it’s way to the compressor
  • The fan for the Blower will run at higher than normal temperatures and that leads to premature failure

Did you know?  Others things that can result in diminished air flow are: collapsed duct work, bad blower motor and low refrigerant charge. This will cause the evaporator coil and suction line to freeze.  Ask the experts:  Cleaning blowers and coils can add up to 30% increase in air flow, prolongs systems life and greatly reduces energy consumption.


…supplies low voltage to heating and cooling control circuits

gtu-transformerCauses of failure:

  • Control shorted in system
  • Low volt wiring shorted or grounded
  • VA capacity too low for system
  • Unit over-taxed by controls
  • Transformer coil shorted
  • Improper primary voltage
  • Power spike or lightning strike

Did you know?  When a transformer fails, it is almost always an indication of further system failure.  Ask the experts: Be sure to mention any new construction or remodeling to your service professional.  (A nail or screw inadvertently driven into a wall may be the cause of a short in thermostat wiring.


…is the heart of your system

gtu-compressorHeat pumps & AC units move heat by circulating refrigerant through indoor and outdoor coils at different pressures.  Changing a shorted or “burned out” compressor involves:

  • Removing the refrigerant
  • Cutting out the bad compressor
  • Welding in a new compressor
  • Changing any drier & using an “HH” type drier
  • Cleaning the line of debris, using a high performance vacuum pump to remove any air or moisture
  • A micron gauge is used to determine the level of deep vacuum
  • Weighing in the manufactures recommended amount of new refrigerant

Causes of failure:

  • Inaccurate refrigerant charge
  • Dirty coils/lack of air flow
  • Improper installation techniques
  • Lack of proper maintenance
  • Power fluctuations/improper voltage

Ask the experts:  Anytime a compressor fails, it is a good idea to consider a new system.  See tips for buying a new air conditioner

Thermostatic Expansion Valve (TXV)

…device that regulates the flow of refrigerant into the heat absorbing coil

gtu-txvCauses of failure:

  • Loss of bulb charge
  • Debris clogging the valve
  • Age seizing moving parts

Did you know?

  • A bad TXV could be a sign of a failing compressor
  • To change a TXV requires all the steps needed when changing a compressor

Ask the experts: A bad TXV may mean it’s time to consider a new system.


… controls heating & amp; cooling systems and allows the indoor fan to run continuously or intermittently

thermostatsCauses of failure:

  • Worn thermostat or sub-base
  • Low voltage wiring shorted or grounded
  • Defective heating or cooling controls
  • Electrical or mechanical failure
  • Power spike or lighting strike

Did you know?  When a thermostat fails, it can be an indication of further system problems.  Ask the experts:  When your thermostat needs to be replaced, it is wise to consider a programmable touch screen type to reduce energy consumption.

EZ Trap Safety Switch

…designed to prevent costly water damage

gtu-ez-trapThe EZ Trap Safety Switch is designed to prevent costly water damage by shutting off your system any time the condensate drain line becomes plugged or blocked.  The clear p-trap and brush are designed to allow us to see any blockage & allow access to clean out the trap easily.  For more information visit www.eztrap.com Did you know?  The EZ Trap will prevent costly drywall damage and prevent excess moisture that can be a source of mold and other unhealthy conditions in your home.

NSI 3000 Low Level Carbon Monoxide Monitor

…the most advanced low level Carbon Monitor available

gtu-carbon-monoxide-monitorFeatures of this unit:

  • An advanced electro mechanical sensor designed to accurately measure low levels of carbon monoxide (CO) providing an early warning of toxic CO levels in your home
  • Detects CO continuously
  • Resistant to false alarms caused by normal household contaminants
  • Digital readout of CO in parts per million (PPM)
  • A continuous circling line on display when the reading is below S PPM
  • 2 year limited warranty

Did you know?

  • Carbon monoxide kills thousands of people each year and injures many more
  • Like oxygen, CO enters the body through the lungs during the normal breathing process
  • It competes with oxygen by replacing it in the red blood cells
  • Reduces oxygen to the heart, brain and other vital organs
  • In high concentrations, CO can kill in minutes

For more information on CO visit www.carbonmonoxidekills.com  Ask the experts:  Low level exposure (Less than 35 PPM) to CO can be confused with flu like symptoms, food poisoning or other illnesses and can have significant long term health risks if left untreated.


…tool that measures air pressure in the duct

gtu-magnahelicDid you know?

  • All HVAC Systems are designed to work at or below 1″ water column (measurement of pressure)
  • If your static pressure is too high your AIC unit may fail prematurely
  • High static pressure also makes your unit work harder, resulting in higher than normal utility bills.

Ask the experts:  The most common cure for high static is adding a return duct to allow your system to breathe.

Combustion Analyzer

…test to determine proper combustion in gas appliances

gtu-combustion-analyzerDid you know?

  • 90% of gas furnaces have never had a certified combustion test completed
  • Without a combustion analyzer test your system may be producing excess carbon monoxide and wasting energy
  • Comfort Club members receive an annual combustion test included in your membership

Meg Ohm Meter

…tool used to test motor windings

gtu-meg-ohm-meterDid you know?

  • A motor or compressor that tests in the caution range is a sign of potential failure
  • If you can catch a compressor with weak winding you should change it before it has a “burn out” to prevent contamination of your system

Ask the experts:  Any time a compressor fails it is wise to consider a new high efficient system.

Choose AC by J for Air Conditioning, Heating & Plumbing in Phoenix, AZ

We offer the fastest, most reliable service on all makes and models of AC and heating equipment in the Phoenix area. Our technicians obtain ongoing training and hold the highest industry certifications possible, so you will receive dependable and efficient service with every visit. No matter the time of day, customers throughout the Arizona area have come to depend on us for all their plumbing, air conditioning, and heating needs. As a local, full-service plumbing and HVAC company, we are ready to help solve any home comfort problem you have.

We are proud to offer:

  • 3 Hour Response Time Guarantee
  • 24/7 Emergency Service on All Makes and Models
  • New System Installation
  • Emergency Repair
  • A Satisfaction Guarantee
  • Complete Staff of Professional Master Certified Technicians

Schedule an appointment for heating, air conditioning, or plumbing services in Phoenix and the surrounding areas.

We offer reliable HVAC and plumbing services throughout Arizona, including the following areas:

  • Anthem
  • Apache Junction
  • Avondale
  • Carefree
  • Cave Creek
  • Chandler
  • Fountain Hills
  • Gilbert
  • Glendale
  • Goodyear
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  • Peoria
  • Phoenix
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  • And More!
Air Conditioning By Jay, Inc. BBB Business Review
Air Conditioning By Jay, Inc. BBB Business Review