Rattling noise in a/h


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Old 02-24-09, 05:08 AM
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Rattling noise in a/h

Hi there,

I have a Janitrol A36-10 that is the same age as the house (1994). I'm getting the house ready for the market and I've noticed that when my heater starts up the a/h has a rattling noise. I mostly notice is from the intake portion (below the a/h). I just recently had a connector (relay?) fixed in the outside unit that made a strange (humming?) sound, but this sound is different - it doesn't happen all the time; maybe 3 out of 5 times when the unit comes on. And it still seems to be working fine. I'm just trying to get a list of things to look for so I can go trouble shooting.

I appreciate any help you can give!
 
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Old 03-04-09, 10:29 AM
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Just following up on this. Was hoping someone could give me some ideas.

I went in the air handler area to try to figure this thing out. When the noise is happening and I open the closet door to the a/h, I don't really hear the noise. However, I really hear it down below from the filter area and where the coils are. A few of the screws seem loose on the coils. Have you heard of coils making noise like this before?

Any help you can provide would be helpful.

Thank you!
 
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Old 03-05-09, 05:26 AM
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There could be so many reasons, I would start by making sure the blower mtr and wheel are good to go. No excessive end play at mtr shaft, wheel and mounting brackets are tight. Check to see if any bundles of wires came loose from mounting grommets etc. check all access panels. It may take you a while but you should be able to find the source of the noise.
 
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Old 03-05-09, 04:20 PM
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Sorry you seemed to fall in a crack.

Does it sound like a metal rattle?

Are there two returns? Could be a damper.
 
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Old 03-05-09, 07:37 PM
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Hey there,

Thanks for your response. It does sound slightly like it could be metal. It only happens on and off.

Today I turned on just the fan and it didn't make the noise, nor did it on when I turned on the A/C.

So, it seems to only be happening with the heater.

I was wondering if there's some kind of defrost mode or something like this. It seems to really happen when the heater is working hard - when it's pretty cold.

How do I check the damper?

Thanks!Beer 4U2
 
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Old 03-07-09, 11:11 AM
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Hmm, makes me think you might have a check valve in there that allows full flow around metering device (piston, txv) in heating.

Could be sticking valve or low charge.

Can you remove the access panel and look at the evap coil?
 
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Old 03-09-09, 06:56 AM
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Yes, I can take off the panel cover and see the coils from above, or I can remove the air filter cover and see the coils from below.

Thanks!
 
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Old 03-09-09, 03:16 PM
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Good.

Can you gain access where you can take a pic of where the larg and small pipes attatch to the coil? Then post here or on photobucket or something?
 
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Old 03-09-09, 08:02 PM
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Hey there,

Okay, I'm able to get the top portion of the panel off, but not the panel that is right in front of the coils. Part of the coil goes through this portion of the panel.

I've taken some pics. I hope you can see what you're looking for. I've taken them from the top and bottom. They're rather large. I had resized them at first then realized that may not be such a good idea. So some of the files are a bit large. You can find them at these links:

Coil01
Coil02
Coil03
Coil04
Coil05

I know they're dirty - I clean them each spring before starting up the A/C.

Also, another thing I should mention is that when I have tried to find the sound (while it's making the sound) when I remove the air filter the sound changes or goes away. But then comes back while the filter is still off.

Let me know if these help. Or if you need another angle if I can get to it. Thank you so much!!!!
 
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Old 03-09-09, 08:29 PM
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I had the same problem with my furnace several years ago. It was a rattling sound that only occured when the heater was running. It turned out that the blower housing was a little loose. I simply wedged a wooden shim between the tabs of the housing and the a/h unit to tighten it up, which solved the problem.
 
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Old 03-10-09, 04:19 PM
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No help. I was looking for something like this.



See the brass txv in the center (with gray top). Older units used to have a checkvalve installed to allow for full flow around it in heating mode.

I'm thinking this is the problem you are having.
 
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Old 03-10-09, 06:41 PM
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Okay, I'll try again to get that panel off to see if I can get in there. Thanks!
 
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Old 03-14-09, 03:13 PM
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Got the pics

Okay, sorry this took so long. Just have to make sure I have to time to tear everything apart. I was surprised at how easy it was to get the lower panel off - the plastic covers that cover the plastic tubes (no idea what these things are) came right off.

Anyhow, got three shots that look pretty good. I hope I'm getting what you're looking for. Here they are:

Image 1
Image 2
Image 3

Let me know if this is what you're looking for.

Thanks you sooo much!Beer 4U2
 
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Old 04-05-09, 09:03 AM
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Sorry it's taken so long to get back.

See where one line connects to a fitting and becomes 4 small ones?

There is a piston in there that allows full refrigerant flow in heating. That is probably the rattle. Points to low charge to me.
 
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Old 04-05-09, 11:17 AM
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Really? Wow. I had the coolant refilled last summer. Had to replace ... can't remember the name ... metal canister in outside unit - the one that rusts - which made my tech guy have to refill.

Thanks for that! Very, very much! I'll have him look into it.
 
 

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