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Discussion Starter #1
I don't want to fix something that ain't broke, but I'm curious about the pulsation in the condensing unit? It's enough to cause a slight rattle in the housing sheet metal. Someone sleeping in the guest bedroom hears it clearly.
 

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That is not unusual.

If you can have it sit on some rubber mounts then it may go away.
 

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That is not unusual.

If you can have it sit on some rubber mounts then it may go away.
Thanks. I ordered some pads but when I went to put them in and found it already had them.
 

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Are the freon lines tight against the hole in the house wall they pass thru?

If so try loosen them and put some rubber between them and the wall.

What is the brand name, model # and age of the unit?

Lennox had a couple models years ago ( XC 15 ) where we had to put some weights they supplied onto the discharge and suction line to change the pitch of the sound.

The 3 ton ones I believe and there was less than 5% of them but a few had a sound.
 

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This is a Bryant 3.5 ton that's about 18 years old. It's always done this. I did put spray foam in the opening where the lines passed thru the brick. That was to stop any insect infiltration.
 

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The liquid refrigerant travelling to the indoor coil can make a flushing pulsating sound and yeah sometimes you can hear it. Usually it is a matter of making sure the freon lines are free floating and not tight against joists/wood.

Depending on which model you have some of those Payne units had pretty light cheap thin cabinets and Bryant/Payne/Carrier are the same.

Point is they can vibrate. I have had to stick pieces of rubber or foam insulation between the cabinet and the wire fins or outside guard to quiet them down.

The newer units are better are there are not too many Builder Grade units anymore.

Post a pic of it.
 

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Pictures. Hope the info decal is readable.
 

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that unit most likely has a reciprocating compressor which is noisier and produces more vibration than a scroll.

there may not be much you can do about it beyond making sure the lineset isn't transferring noise.

you could try a sound blanket.
 
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Reciprocating are MUCH MUCH quieter than a scroll.

Yeah that was one of those cheaper units. You can try stick pieces of foam rubber behind those wires outside the coil and may get it quieter.

Newer units usually have solid fins which protect better against hail but back then a lot of brands had cheap cabinets and were saving on metal. Lennox included.
 

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Reciprocating are MUCH MUCH quieter than a scroll.
Not the ones i've heard.
 

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Not the ones i've heard.
You are not a tech.

How many have you heard?

I have heard tens of thousands of them.:smile:

However everyone is entitled to their opinion. Scrolls make a high pitched ringing sound. Recips are more of a purr.
 

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How many have you heard?
not thousands but plenty - i've found scrolls to be much quieter and units with recips when they were more common had higher sound level ratings.
But sound can be perceived differently.

anyhow would a sound blanket help in this case? may be worth a try.
 

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A blanket may help but it sounds like more of a vibration problem. The blanket won't stop a vibration sound.

I worked on lots of those units when I was a Carrier dealer and those wire grills howl. Only way to stop them is to stick pieces of foam rubber behind them.

15-20 yrs ago was the prime days of Goodman builders grade units and everyone followed suit and dumbed them down.
 

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Discussion Starter #14
Reciprocating are MUCH MUCH quieter than a scroll.

Yeah that was one of those cheaper units. You can try stick pieces of foam rubber behind those wires outside the coil and may get it quieter.

Newer units usually have solid fins which protect better against hail but back then a lot of brands had cheap cabinets and were saving on metal. Lennox included.
I slipped a wood shim under the cage on top on one side and stopped the rattle but the pulsing is still there. I'm okay with it. Thanks guys!
 
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