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I apologize if this is not the right place for this post. But I am not sure where to get advice. My heatpump/air conditioner is about five years old. Last summer it needed freon twice. The first time the service man was too busy to check for a “small leak” and suggested I set up a leak check appointment. Five days later the unit was completely out of freon again. This time the service man found a leak (two freon lines at the furnance coil rubbing together wore a hole in the high pressure line.
He charged the unit and we have been pleased with it’s operation. This year the compressor is having trouble starting. It moans once, twice sometimes three or more times before it kicks in. The house lights dim with each starting attempt and I swear that the double 60A breaker makes a moaning sound as well. Note-the breaker does not pop.
I checked that the breaker connections were tight. I would suspect a starter capacitor failure except that would be a total failure and the compressor would never start. Right? The house and compressor fans work fine. Once the unit starts, it runs cold. Any thoughts?
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First, The unit runs cold: could be low on freon (will often short cycle, on-off,on,off), could be clogged filers or some other reason that air isn't flowing across evaporator fast enough (evaporator will tend to freeze up)
Second, compressor starts hard but does run: could be one shorted winding in compressor, could be defective capacitor, insufficient oil, defective relay closing only one leg or closing one (or both) leg with high resistance.
If you have a "bleed" tube or a thermostaticly adjusting expansion valve, these usually allow the high pressure side to bleed into the low pressure side so that the compressor isn't starting against so much pressure. A defective expansion valve or clogged bleed tube could cause this problem.
A common fix for hard to start compressors is to add a "hard start kit". This is just another capacitor that's added in parallel to the one you've already got.
*Thanks for your reply.Just talked to manufacturer. The unit is under warranty until Nov, 2000. The A/C side is cold so that is good. Winter the unit ran warm. Compressor is working good. My concern with using a "hard start kit" is: 1. Unit worked without a hard start kit for over four years. 2. The "hard start kit" could mask a motor problem, i.e. a rotor locking up, until after the warranty expires. I also found out that the manufacturer recommends a 50A min. breaker. A 60A breaker is now in the circuit. I guess that is why the breaker has not popped given that the house lights dim as it tries to start.
*Herb: A 50- or 60-amp breaker for a induction motor is a huge load for a residential service. I suspect that your lights dimmed for the first four years as well. A 60-amp breaker won't trip immediately if current exceeds 60 amps, there's a time-overcurrent relationship something like 70 amps for 1 minutes, 100 amps for 6 seconds, or 200 amps for 2 seconds will cause it to trip. Otherwise your Skilsaw, nameplated at 13 amps would always pop a 15- or 20-amp breaker on start-up when it pull many times (3 to 6x) it's running amps. But jam it in a piece of wood and pull 40 or 50 locked-rotor amps for a few seconds and the breaker will pop.All of this is to say: don't worry about the lights dimming, that's to be expected when you pull so much starting current. But do worry about the change of behavior as it may indicate one of the problems Ryan listed.Another helpful forum, more oriented to HVAC is:http://www.heatinghelp.com/-David
*Thanks for your comments.The problem was a bad start capacitor. The old one wasbadly corroded at the terminals. I guess the unit was startingon the run capacitor. FYI a good source for AC/Heat Pump help is http://www.hvachelpu.com