york a/c unit

[jj34]

One of our a/c units is making a horrible noise when it shuts off. York model# H2RC042S06B. It's probably around 6 yrs old. It almost sounds like a lawnmower when it shuts off. I'm sure the neighbors love us since it's right outside their bedroom window. The fan comes on in the house and it cools fine. We haven't had it on with it being winter, but now it's getting warm and I need to get it fixed. Any help with this would be greatly appreciated. :X

[RegUS_PatOff]

vibrations of/in the Compressor ?

[jj34]

Is that something that would need to be replaced or can it be repaired? How do I check to see if that's it? Please be patient. I can do most anything if given the right direction, but my primary vocation is mom.

[RegUS_PatOff]

You'd have to get up close, and take a listen when it's running and shuts off to see what's making the noise.

[dkpd1581]

If the noise sounds like an old manual push mower the cause is typically your fan motor bearing on the condenser fan motor.  Turn the unit on, walk outside, turn off the disconnect located next to the outdoor unit, listen for the sound as the outdoor unit shuts down.

If it is in fact the fan motor making the noise, the bearings are going bad.  The only remedy is to replace the motor and capacitor.  I recommend replacing the blade as well.  Old blades on new motors sometimes cannot stand the stress imposed by the new motor and crack or break.  Furthermore, the old blade can be damaged on removal from the old motor and can possibly be out of balance.  Spend the money.

[Bobice]

Look at the fan blade on the outside unit. You may have debris.

[Cactus Bob]

we call that the "put put" sound  it comes from the compressor . the output (high ) pressure discharge  has a check valve inside the compressor itself  .when it goes bad it leaks backwards ... so you compressor turns off and then the leaking check valve turns the compressor backwards . and you get the put -put sound  . this will not do damage anything at first but as more and more gas leaks through it the compressor will be runing faster backwards and at some point that will brake something and kill it .... carrier made a in line check valve to fix this problem ( can be used on any copeland scroll) but must be installed by a service tech . by the way you are talking about it i think your past that point and will need a new compressor

[Bobice]

[user=33613]Cactus Bob[/user] wrote:

we call that the "put put" sound  it comes from the compressor . the output (high ) pressure discharge  has a check valve inside the compressor itself  .when it goes bad it leaks backwards ... so you compressor turns off and then the leaking check valve turns the compressor backwards . and you get the put -put sound  . this will not do damage anything at first but as more and more gas leaks through it the compressor will be runing faster backwards and at some point that will brake something and kill it .... carrier made a in line check valve to fix this problem ( can be used on any copeland scroll) but must be installed by a service tech . by the way you are talking about it i think your past that point and will need a new compressor

Unfortunately that model does not use a "Scroll" type compressor.

[Bobice]

From Copeland's Guide to Scroll Compressors

1. Loud, very loud, relief sound coming from the compressor. [align=left]Some model scrolls have an internal pressure relief (IPR) valve. This valve opens at a discharge to suction differential of 375 to 450 psi (R-22) or 550 to 625 psi (R-410A). Check for restrictions in the discharge line, overcharge of refrigerant or a faulty component.[/align][align=left]2. Shutoff noise.[/align] [align=left] Scroll compressors may run backwards for a brief period at shutoff as the internal pressures equalize. This momentary reversal of direction of the scrolls has no effect on the compressor durability and is entirely normal. Single phase compressors built since May 1995 have a device which prevents the reverse rotation and eliminates the noise. Three phase models have a device which reduces but does not eliminate the noise.[/align][align=left]3. Shutoff sound.[/align] [align=left]The reversing valve should be wired so that the valve does not reverse when the system is shut off by the operating thermostat in the heating or cooling mode. If the valve is allowed to do this, suction and discharge pressures are reversed to the compressor. This results in a condition of system pressures equalizing through the compressor which can cause the compressor to slowly rotate until the pressure equalizes. This condition does not affect the compressor durability.[/align]