InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.Seized air conditioner or heat pump compressor motor diagnosis:This air conditioning repair article discusses theDiagnosing Tight or Seized Air Conditioning Compressors and how to re-start a tight air conditioning compressor. Advice for measuring amps or current draw to check for a seized or tight or failing A/C or heat pump compressor motor.See the basic diagnostic steps suggested for A/C and heat pump damage indications and causes. Here we continue with details about examining and measuring A/C and heat pump compressors to continue compressor condition diagnosis.We also provide a to this topic, or you can try the page top or bottom as a quick way to find information you need.
An engine that was in a covered shed, had no visible sign of water infiltration, and was full of oil and coolant- but stuck- is usually an easy fix. The rings, which are cast iron, are usually stuck to the cast iron cylinder walls but only in the cylinders which are open to the atmosphere.
Diagnosing Tight or Seized Air Conditioning CompressorsSometimes a compressor may be internally damaged or worn in a way that makes the piston(s) run tight in the cylinder(s) rather thanloose and worn (loose or worn air conditioner compressor diagnosis is describedat ).A tight or seized air conditioner compressor might occur, for example, if the compressor ran while low on oil.Or perhaps if the compressor is old and has not been run in some time. The A/C compressor may refuse to start at all, or may be hard-starting depending on when it last ran and what it's temperature is.A 'hard starting' 'tight' air conditioner compressor will probably draw excessive current (Amps) duringstartup, so that measurement may be used as part of the diagnosis of this problem.
134Notes to the table above1 using WPC44H series packaged air conditioning systems as an example. These units operate at 208-240V single phase electrical supply.Note that these amperage figures are NOT the total amperage draw for the unit, they are specifically compressor motor amp draw data.These FLA and LRA numbers are for example purposes only. Other compressor motor models and brands will have different, if generally similar by order of magnitude amperage draw numbers.The apparent inconsistency of Amp draw increase in these tables is most likely due to variations in compressor motor designs among the different BTUH-rated units. 118Notes to the table above 1 using WGPH45 series packaged heat pump systems as an example. These units operate at 208-240V single phase electrical supply.Note that these amperage figures are NOT the total amperage draw for the unit, they are specifically compressor motor amp draw data.These FLA and LRA numbers are for example purposes only. Other compressor motor models and brands will have different, if generally similar by order of magnitude amperage draw numbers.
Locked Rotor Amps - LRA compressor motor dataThe current draw in AMPS during compressor motor start-up can also be compared to the unit's specified LRA or 'lock rotor amps' found also on the data tag we describe above. However most HVAC repair technicians look at the compressor motor FLA reading since that's the running-condition of the unit. LRA in some references is also referred to as 'starting current inrush' - the amount of current drawn, in amps, when full voltage is applied to start up the electric motor, in this case in the air conditioner or heat pump compressor.Example LRA data is found for both air conditioning compressors and heat pump compressors in the two tables above. Other sources give typical LRA numbers for typical 240V A/C compressors will typically be about 33 Amps per ton or 33 Amps per 12,000 BTUH for up to 3 ton units. So a two ton unit will draw 66-67A, a 3-ton unit 100A during startup only.Larger compressor motor units do not continue this almost straight line increase in current draw.So a 4-ton A/C compressor may draw a bit under 120A, and a 5-ton unit 145A. All of these current draws are only during motor start-up and are at 240V AC.What's the difference between FLA and RLA Amperage Current Draw Ratings?The reason you see us using 'RLA/FLA' in the center table column is that these are about the same thing.
The term 'Full Load Amps' or 'FLA' was officially changed to 'Rated Load Amps' or 'RLA' back in 1976. Regardless of calling it FLA or RLA, this is the maximum current the motor should draw during any running conditions.Note that this excludes high amp load during motor start-up. On modern air conditioners and heat pumps you should see RLA marked on the motor data plate. If you are reading an older article referring to 'FLA', think RLA.Some technicians and electricians apply RLA to compressor motors and still use FLA for other motors.
RLA is used in circuit wire sizing.Watch out: don't mix-up RLA (running load amps) with LRA (locked rotor amps). LRA is discussed above as well. Question:seized compressor motor(June 10, 2014) SUSAN said:We were told our compressor seized. Had a new one installed (old one was about 7 yrs. Old) and then it stopped cooling 1 hour later. Serviceman came back and it stopped cooling after an hour again.Week later, we were told the coil and air filter were dirty and the handler was improperly installed. Air handler was never checked before the compressor was replaced.
![What Is A Seized Motor What Is A Seized Motor](/uploads/1/2/5/3/125377685/619454472.jpg)
![What does a seized motor mean What does a seized motor mean](/uploads/1/2/5/3/125377685/220894735.jpg)
Had the company that installed the handler 2 years ago come and they said the coil needed to be cleaned and we needed 4 lbs. Lbs of frion in brand new compressor ). Compressor was just replaced b/c while it ran, it did not cool. Should the air handler/coil been checked before the compessor was replaced? Who do we believe? Reply:Possibly the burned out compressor replacement procedure did not adequately clean the refigerant system from debris and perhaps a burnout filter drier pair were not installed on the new system. The result could be clogging of the expansion valve and loss of cooling.Actually cleaning a dirty coil is of course a different and totally external step.Continue reading at or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.Or see these HVAC Compressor Articles.
PDF.Suggested citation for this web pageat - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice. INDEX to RELATED ARTICLES:Or use the found below to Ask a Question or Search InspectApedia. Thanks to, Tampa Florida, for assistance in technical review of the 'Critical Defects'section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Cramer is a Florida home inspector andhome inspection educator.120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email:. The firm provides professional & &.
Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home.