HVAC Vibration

[XR250]

Ok, be gracious with me. I am an SE on this site but have an HVAC question. I built a new house (one story ranch on a crawlspace) and the HVAC contractor installed a 15 SEER American Standard unit. As it was a perfectly straight shot from the outdoor unit thru the crawlspace to the air handler in the mechanical closet, the contractor used ½”ø rigid copper for one of the lines. Seemed like a good idea. However, when the unit runs I hear a vibration in the house and outside. It is kind of a beating vibration like “wah, wah, wah” I can’t imagine a unit leaving the factory with a vibration. I am figuring that the rigid line is causing this. They have been back a few times to add isolators etc. and it remains. I had this same unit at my old house and it was pretty damn quiet. Does anyone have any further insight about this?

Thanks

 

[AgMechEngr]

How is the pipe supported? Added isolators where?

It is possible for units to leave the factory with issues. I had a unit with some electrical issues, and the technician found that the wiring was backwards. He looked up data on its manufacturing, and it was wired at 3:30 PM on a Friday afternoon.

 

[MintJulep]

Run evaporator blower by itself. Hear the noise?

Run condenser fan by itself. Hear the noise?

 

[LittleInch]

These can be difficult to isolate.

The main noise producing element is the compressor. The internal dampers my be damaged or the resilient feet on the main unit are not installed correctly.

If the hard pipe is connected directly to the main unit with no flexible piping involved then that is a major source of vibration transmission.

Pictures help a LOT

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LittleInch]

Is it one of these?

https://americanstandardair.com/assets/product-brochures/asa-air-conditioner-brochure-12-11-22.pdf

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[XR250]

Yes, that is the unit - silver Series.
It is def. the outdoor unit. Running the AH by itself is pretty silent.
I'm having another company come by next week to get a second opinion and a fresh set of eyes on it.
I still think it is the rigid pipe causing it. I'll check back when I hear something.

Thanks

 

[LittleInch]

If it's audible outside as well it is more likely to be the main unit or something inside it is not properly damped or the rubber bushes have been damaged.

Also check the fan clearance or louvres for any signs of damage or foreign object (mouse?)

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[XR250]

Thanks. Def. not any fan interference.

 

[LittleInch]

How long is this copper pipe? There may be issues with it contracting ( I assume it's the chilled water supply line) and imposing force on the connection and hence forces going into the unit it wasn't designed for? Some level of flexibility is needed to avoid this.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[XR250]

It is residential so it is a freon line. It has a an elbow in it going up thru the floor to the air handler which should absorb that stress

 

[chicopee]

Go to the discharge end of the capillary tube and note for any undue noise by touch or hearing. A stethoscope may help if by hearing.

 

[XR250]

Update:

Had another technician come out. He thinks the compressor is out of spec. It is pulling too many amps. The charge is ok. They are going to investigate further.