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Noisy compressor

5K views 22 replies 8 participants last post by  plummen 
#1 ·
In one bedroom where it is right next to the air conditioner compressor which sits outside on a concrete pad, I can hear the compressor hum pretty loudly even with all the windows shut.

I don't remember if this has always been the case. It's a guest bedroom I honestly don't remember it being this loud but I rarely use that room so can't say for sure.

I know my units are old and may be time for replacement, but it works and cools just fine.

Here are the model & serial numbers, and not sure how old. It was installed by a previous owner.

HANDLER: LENNOX Model CB30M-31-1P Serial 5899K 5321

COMPRESSOR: LENNOX Model HS27-030-1P Serial 5899L 61774

Are these old? Is the noise due to old age, or I need to find a way to insulate the sound? What can I test or try to figure out which way to go?
 
#2 ·
Made in 1999 so they are not young or real old. Those don't usually get louder with age but it should be checked by a Pro. Freon level needs checking etc. Usually I sit them on some rubber to absorb the vibes. If it is low on Freon the compressor can get damaged and your cooling goes down and elec goes up.

15 yrs use in Miami is LOTS and you should budget for new ones but some of those Lennox units can easily go more than 20 yrs. Get it properly checked and it may last another 5 yrs.
 
#5 ·
At 15 yrs old the fan motor is worn and in your climate has several yrs more wear than the average unit. Probably needs a new motor and most of them are sealed and non lubricateable. Post a video on U Tube with the sound of it. Don't know about the blanket.
 
#6 ·
About the blanket:
I've got a 13 SEER Goodman with Copeland scroll and a cheap stamped fan. With a Rheem 68-23427-26 blanket on it (fits 1.5-3 ton Copeland) I can barely hear the compressor because the fan is louder than the compressor. I'm not sure what it would be like if I had a quieter fan, but my compressor is no longer a factor in outdoor noise.

Also, make sure it's the outdoor unit you hear and not the lineset transferring vibration to the house.
 
#13 ·
Miamicuse:

The entire outside unit is called a condenser. Inside it sits the compressor and on top is the condenser fan motor. What exactly is the problem? From the looks of it, just the condenser fan motor is the problem. Those are around $100-$200 and an easy DIY swap. Are you saying the compressor inside is making the noise?

Replacing the entire outside unit will also mean replacing the evaporator inside your home. You are looking at many, many thousands to replace the entire thing.
 
#8 ·
yuri,

here are two youtube videos.

the first one is the noise I hear when standing inside the room looking at the compressor outside.

https://www.youtube.com/watch?v=vnHEHxAUopg

the next one is the noise made by the compressor outside. I deliberately move around the unit, up and down, so you can hear the difference. You can also see the concrete pad the unit sits on is not touching the building structure.

https://www.youtube.com/watch?v=sML2JGt8KdE

To me it sounds like the fan on top is the most noisy.

Any advice or comments would be greatly appreciated.
 
#14 ·
wheelsup I got my terms mixed up.

I meant the condenser unit outside the house, not the inside air handler unit. The inside unit is fine when it runs all I hear is the air being sucked in and if I close the closet door it's fine.

The outside unit is one that when I am in one room even with windows closed I thought it was a plane flying over.

So I just need to look up the make & model of the fan motor and replace it? No need for any sound blanket or dampening feet etc?
 
#16 · (Edited)
Hi after searching online I found a place that carries the motor.

I think it is this one:

http://www.acfurnaceparts.com/search.aspx?find=68j97&log=false&category=24

68J97 Lennox - Fan Motor

Your Price: $276.40

Is this right? Do I need anything else? Do I need to change out the capacitor too at the same time?

Thanks for all the comments and suggestions so far!
I think you should do some research and educate yourself on the various components of your outside unit (and indoor unit), gain some general knowledge about the units so you can talk at a similar level to those helping you (not me, I'm not a tech), and show a genuine interest in learning to troubleshoot not just throw parts.

This whole video won't apply to you but the first couple minutes show you how to troubleshoot a bad fan motor. It also discusses the cap and how to test if it's good or not.

https://www.youtube.com/watch?v=u5crdrc8jPE

Throwing parts at a unit is never a good idea IMO. Me personally, I would never buy a $300 part without doing some diagnostics first, at least pull the shroud off and feel the shaft/bearing play on it.

Prior to that the extent of my knowledge about AC units was about zero. Guys here helped me understand the components and taught me how/what to troubleshoot. This is a great resource but you need to put in the effort on your side IMO.

Here is the multimeter I used, don't forget your 25% coupon:
http://www.harborfreight.com/5-in-1-digital-multimeter-98674.html
 
#20 ·
You are right.

I mentioned in the beginning it is a room I rarely enter, a guest bedroom.

I am expecting a guest soon and when I went inside to set up the room that's when I noticed the noise. It was loud enough with windows closed for me to thought it was a plane flying by overhead. Then it occurred to me it's the AC outside. Since then it's been bothering me because now that I noticed it I am wired to notice it more.

Two years ago I had an AC tech come by because the handler stopped working - it froze there was a sheet of ice on the inside. He told me my units are both living on borrowed time and quoted me a new set for about $5500.
 
#18 ·
It is not abnormal but louder than when new as the bearings are worn in it and possibly the fan blade is off balance from running that way for a long period of time. Most people don't care or want to spend $$ and run it that way until it stops.
 
#21 · (Edited)
Does not sound abnormal to me. Why spend $$ if you don't have to.

Those blankets we use on newer Scroll compressor units as some have a different pitch in sound than the old reciprocating ones which you probably have, Not going to do much for you and you may not find one for a recip easily.

Seriously, I worked shift work and use those disposable foam ear plugs to sleep in the day. If the guest has a problem try them. They are comfy.
 
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