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AIR CONDITIONING & HEAT PUMP SYSTEMS
A/C - HEAT PUMP CONTROLS & SWITCHES
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR FILTER EFFICIENCY
AIR FILTERS, FIBERGLASS PARTICLES
AIR FLOW MEASUREMENT CFM
APPLIANCE DIAGNOSIS & REPAIR
APPLIANCE EFFICIENCY RATINGS
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BOOKSTORE - Air Conditioning "How To" Books
CAPACITORS for HARD STARTING MOTORS
CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
DEFINITION of HEATING & COOLING TERMS
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DIAGNOSTIC GUIDES A/C / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DUCTS - Asbestos
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCT SYSTEM & DUCT DEFECTS
DUCT SYSTEM NOISES
DUCTS, Asbestos Transite Pipe
DUST, HVAC CONTAMINATION STUDY
ELECTRIC MOTOR OVERLOAD RESET SWITCH
EVAPORATIVE COOLING SYSTEMS
FAN LIMIT SWITCH
FAN NOISES, HVAC
GAS EXPOSURE EFFECTS, TOXIC
GAS DETECTION INSTRUMENTS
HEAT LOSS (or GAIN) in buildings
HEAT LOSS (or GAIN) INDICATORS
HEAT LOSS R U & K VALUE CALCULATION
HEATING SMALL LOADS
INSPECTION CHECKLIST - OUTDOOR UNIT
INSPECTION LIMITATIONS, A/C SYSTEMS
LEED GREEN BUILDING CERTIFICATION
LOST COOLING CAPACITY
LOW VOLTAGE TRANSFORMER TEST
MOTOR OVERLOAD RESET SWITCH
MOLD in AIR HANDLERS & DUCT WORK
OPERATING COST, AIR CONDITIONER
OPERATING DEFECTS, AIR CONDITIONING
REPAIR GUIDES A/C / HEAT PUMP
REPAIR & DIAGNOSTIC FAQs for A/C
THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES
WATER COOLED AIR CONDITIONERS
WINDOW / WALL AIR CONDITIONERS
WINDOW / WALL A/C SUPPORTS
This Air Conditioning Troubleshooting & Diagnosis FAQ (list of frequently asked questions about air conditioners) lists the major areas of investigation to be followed in diagnosing all types of problems with air conditioning systems and heat pump equipment.
Typical air conditioner concerns include compressor or blower assembly noises, failure of air conditioners to start or to keep running, inadequate cool air flow or air quantity, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply, or even loss of air flow entirely.
Also discussed are various electrical wiring, fusing, overcurrent, and thermostat or control defects on air conditioners.
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Since the failure of an air conditioner to turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply, or even loss of air flow entirely can be due to a variety of problems with one or more components of an air conditioner or air conditioning system, after reviewing the lost air conditioner cooling diagnosis procedures described in this article, be sure to also review the diagnostic procedures at each of the individual air conditioning diagnosis and repair major topics listed just below. To return to our air conditioning and refrigeration home page go to AIR CONDITIONING & HEAT PUMP SYSTEMS.
If your air conditioning or heat pump system has lost its cooling capacity or won't start select one or more of the diagnostic articles listed below.
Continue reading at DIAGNOSTIC GUIDES A/C / HEAT PUMP or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs)
Question: air handler trips circuit breaker
(July 23, 2011) Air Handler tripped breaker said:
The motor checks ok no ohn reading on each leg of 110v side of motor, capacitor has ohms of resistance no swelling. Either the mother board or the relay.
With power off, check first for shorted electrical wiring, next for a seizing motor or a motor with a bad start capacitor.
Question: AC blower short cycling on-off betweeen heating and cooling
(July 29, 2011) Charles Gullette said:
I recently had a new 3 ton 13 seer unit installed. It included a new compressor, condenser, and cooling coils and digital non programable thermostat. The existing 3 ton blower and heater unit were reused.
After installation the blower unit starts, runs about 15 sec and then restarts. there is no effect on the compressor unit. My tech. says the blower is starting on the heater relay and then shifting to the cooling relay on the blower control board. He claims this is not a problem but that the board may need changed in the future. I did not have this problem prior to the new unit installation. Could it be the thermostat wiring or is my control board going bad??
Charles, I wonder if the new thermostat was wired exactly the same as the old one? And I agree that the circuit board could otherwise be the problem. I also agree that it's curious to have to change a circuit board after other components were swapped out unless either there is a compatibility issue (sounds wrong) or an accidental short circuit, or some mechanical disturbance that just pushed a failing component over its edge.
Question: AC making revving up sounds
(Aug 27, 2011) AC making "revving up" sounds ev said:
When my AC (Trane) is running is sounds like someone is revving an engine every few minutes. The indoor part of the system is in the attic and when the "revving" noise happens the sound below, in the house, is like a "Blue Northern" strong wind.
AC making revving up sounds
I'm not sure about revving up - perhaps a cycling of a motor trying to start? or a loose fan blade hitting something? AC making revving up sounds
Question: 0 PSI on compressor high side
(Jan 2, 2012) george said:
Hi new goodman h/p getting 0 psi on high side? help
sounds as if the compressor motor is not working at all
Question: switching to cooling mode blew 24V transformer
(Mar 24, 2013) james said:
i put t-stat in cool 24 volt transformer blew what caused this
Perhaps a short circuit in the thermostat wiring
Question: water leaking out of air conditioner
my air condition is leaking water out of it
Look for a condensate drain clog or pan leak.
For diagnostic help see BLOWER LEAKS, RUST & MOLD
Questions & answers or comments about how to diagnose and fix air conditioners or heat pumps..
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
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Technical Reviewers & References
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