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AIR CONDITIONING & HEAT PUMP SYSTEMS A/C COMPONENTS A/C DATA TAGS A/C DIAGNOSTIC FAQs A/C REFRIGERANTS A/C TYPES, ENERGY SOURCES AIR CONDITIONER BTU CHART AIR FILTERS for HVAC SYSTEMS AIR HANDLER UNIT DIRTY A/C BLOWERS DAMAGED COOLING COIL DIRTY COOLING COIL DIRTY COIL CLEANING PROCEDURES FROST BUILD-UP BLOWER LEAKS, RUST & MOLD ADDING A/C: RETROFIT SIZING CLEANING & Legionella BACTERIA COMPRESSOR CONDENSER CONDENSATE HANDLING CONTROLS & SWITCHES COOL OFF HEAT Thermostat Switch COOLING CAPACITY, RATED COOLING COIL or EVAPORATOR COIL DATA TAGS on AIR CONDITIONERS COMBUSTION GASES & PARTICLE HAZARDS COMBUSTION PRODUCTS & IAQ DEFINITION of Heating & Cooling Terms DEW POINT CALCULATION for WALLS DEW POINT TABLE - CONDENSATION POINT GUIDE DUCT SYSTEMS DUCTS - Asbestos DUCT SYSTEM DEFECTS DUCT INSULATION, Asbestos Paper DUCT INSULATION for SOUNDPROOFING DUCTS, Asbestos Transite Pipe DUST FROM HVAC? ENERGY SAVINGS in BUILDINGS EVAPORATIVE COOLING SYSTEMS FAN AUTO ON Thermostat Switch HEAT LOSS (or GAIN) in BUILDINGS INDOOR AIR QUALITY & HOUSE TIGHTNESS INDOOR AIR QUALITY IMPROVEMENT GUIDE INSPECTION LIMITATIONS LOST COOLING CAPACITY MOTOR OVERLOAD RESET SWITCH OPERATING COST OPERATING DEFECTS OPERATING TEMPERATURES Air Conditioning System Temperatures Instruments Used to Measure A/C Temperatures Procedures for Making Temperature Measurements REPAIR GUIDE for AIR CONDITIONERS REPAIR & DIAGNOSTIC FAQs for A/C REFRIGERANTS SEER RATINGS & OTHER DEFINITIONS SYSTEM OPERATION OPERATING CONTROLS SAFETY CONTROLS THERMOSTATS THERMOSTATIC EXPANSION VALVES CRITICAL DEFECTS on A/C SYSTEMS FURNACES WARM AIR HEATING SYSTEMS INDOOR AIR QUALITY & HOUSE TIGHTNESS INDOOR AIR QUALITY IMPROVEMENT GUIDE MOLD INFORMATION CENTER More Information InspectAPedia Blog - News Updates Air Conditioning & Heat Pumps Bookstore Electrical Environment Exteriors Heating Home Inspection Insulate Ventilate Interiors Mold Inspect/Test Plumbing Water Septic Roofing Structure Accuracy & Privacy Policies Contact Us |
This chapter discusses exactly how and where to measure input and output air temperatures at air conditioning equipment in order to determine whether or not it is operating properly, as part of checking basic air conditioning system operation and for detection of air conditioning operating defects. An introduction to air conditioner temperatures and some rules of thumb that are quick and easy to apply in diagnosing air conditioner problems are provided at the preceding article: Air Conditioning System Temperatures. © Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website. Procedures for Making Temperature Measurements of Air Conditioning SystemsAir conditioner temperatures that are too high or too low can indicate specific operating problems on central and portable or window air conditioners. Simple measurements of air temperatures, if made at the right place, can assist in diagnosing what may be wrong and what repairs may be needed for the air conditioner. This document is a portion of our website which describes the inspection of residential air conditioning systems (A/C systems) to inform home buyers, owners, and home inspectors of common cooling system defects. If your air conditioning system has lost its cooling capacity or won't start see REPAIR GUIDE for AIR CONDITIONERS. See How to determine the cooling capacity of air conditioning equipment if the system seems to be working but is inadequate to cool your building. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. Refrigeration and Air Conditioning Theory: Refrigeration systems rely on two state changes of the refrigerant: gas to liquid, and liquid back to a gas to move sensible heat from the low side of the air conditioning system to the high side. At the evaporator coil heat (BTUs) is absorbed when the refrigerant evaporates (liquid to gas), and at the condenser coil heat is released during condensation (gas to liquid). R12 refrigerant has a boiling point of -21 degF (change of state from liquid to gas vapor) and R22 has a boiling point of -41 degF. But if you are measuring air temperature close to the evaporator coil or condenser coil you won't record these two temperatures on your thermometer. Rather the temperature that you can record will be significantly affected by ambient conditions. For example, at the evaporator coil the temperature of indoor air entering the coil, the distance between the coil surface and the thermometer, the air velocity, and other factors will produce a temperature reading that is different from and certainly higher than the boiling point of the refrigerant entering the coil. While we may form an opinion about just how cool the air should be right at an evaporator coil, or inside of an air handler supply plenum, most diagnostics look for temperature differences between air entering the air handler and air leaving the air handler to evaluate what's going on in the system. NOTE: an air conditioning technician has more precise tools to evaluate the condition of a system such as gauges to measure the pressures on the high side and low side of the system and an ammeter to measure current draw of the compressor. How to Examine Air Conditioner TemperaturesTemperature Measurements & Observations at the Room ThermostatAir conditioner thermostat settings: observe the settings on the wall-mounted room thermostat (assuming you've already
established that the switches and controls have turned the system on and that it is in cooling mode and has
been operating for half an hour or longer. Temperature Measurements at the Evaporator Coil in the Air Handler How to Measure Air Conditioning Register outlet temperatures using a dial thermometer probe:
we simply wedge the probe of our dial thermometer between the
vanes of a ceiling supply register, or drop it probe-first through the slots of a cool-air supply floor register
where we leave it for at least five minutes. Sketch courtesy of Carson Dunlop. We use tissue or toilet paper to confirm for skeptical owners that
the direction of air flow is "in" at a return register and "out" at a supply register since sometimes this
can be confusing to a novice. Measuring Air Conditioning Duct temperatures using a dial thermometer probe: if there is not an existing duct opening such as a foil-covered hole or a removable plug, we drill a 1/4" diameter hole in the sheet metal of the duct. BE CAREFUL not to drill where you can damage a refrigerant line, coil, wire, etc. After inserting the probe into the hole for measurement, waiting, taking our measurement, we close the hole using a square of adhesive foil tape, duct tape, or snap-in plugs sold for that purpose. Temperature Measurements at the Condensing Coil & Fan/Compressor UnitMeasuring temperatures at an Air Conditioning Compressor: By holding the thermometer's probe in any air path (and patience) it is trivial to measure ambient air temperature, air temperature flowing into the condenser unit at the condensing coils, and temperature flowing out of the condenser at its fan output (keep the probe out of the blades!) Measuring Air Conditioning Temperatures Using an Infrared Thermometer: permits measurement of
surface temperatures such as the surface of a metal duct (is it insulated?), surfaces of
refrigerant suction and high pressure lines (do we know target temperatures?), or surfaces inside
a building. ... Technical Reviewers & References
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website. AIR CONDITIONING & HEAT PUMP SYSTEMS
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AIR CONDITIONING & HEAT PUMP SYSTEMS Air Conditioning "How To" Books FURNACES WARM AIR HEATING SYSTEMS More Information InspectAPedia Blog - News Updates Air Conditioning & Heat Pumps Bookstore Electrical Environment Exteriors Heating Home Inspection Insulate Ventilate Interiors Mold Inspect/Test Plumbing Water Septic Roofing Structure Accuracy & Privacy Policies Contact Us |
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09/27/2009 - 01/31/1995 - InspectAPedia.com/aircond/aircond09c.htm - © 2009 - 1988 Copyright Daniel Friedman All Rights Reserved - InspectAPedia® is a Registered U.S. Trademark