HVAC sound & noise recording questions & answers.

This article series provides diagnostic sound recordings of various noises or sounds made by air conditioners, heat pumps, furnaces, ductwork, or HVAC controls & filters.

A/C & Heat Pump System Noise Recording FAQs

These questions & answers about recordings made of noises at aonditioning & heat pump compressors were posted originally at

On 2017-09-06 by (mod) -

J Scott

I listened to your recording but it was hard to make out just what noise you were hearing. I think there may be a rattling sound.

In a companion article NOISES, HVAC SYSTEM DIAGNOSIS -

we describe various A/C noises and what they usually mean. Please take a look at that article and then we can continue discussing your question.

If the A/C temperature is too low there could be any of several problems: iced-up coil, complete loss of refrigerant, dirty air filter, blocked ductwork.

You need to do some detective work to determine if the root problem, if there is one, is

- weak air flow

- insufficient temperature drop across the cooling coil

- something else like a thermostat not working

On 2017-09-06 by (mod) - sounds like a air nozzle attached to a air compressor

Re-polsting

J Scott said:
I'm wondering if this is a problem or not: you
When AC is on, the outside unit will operate for half an hour or so, and then start making this noise, which sounds like a air nozzle attached to a air compressor blowing high pressure air.

It'll make this sound for a few minutes then return to normal operation for a while and then repeat the same cycle for as long as the AC is on. The AC doesn't blow as cold as I think it should even when not making the high pressure sound.

On 2017-07-24 by (mod) - nit started making a shuddering vibrating noise

Great question, Reid. I'm not sure of an authoritative answer but certainly if the hard-start occurred as a new symptom after adding refrigerant I understand perfectly your question.

Equally or more-likely the compressor was already having trouble that wasn't fixed by adding refrigerant but you might get more compressor life with addition of a hard-start motor capacitor.

Discuss that with your service company and let me know what they san.

On 2017-06-28 by Reid

I have an Intertherm 4 ton unit in a Mobil home.The tech added Freon and then the unit started making a shuddering vibrating noise when i comes on and then runs fine.Could this be a symtom of Freon overfill

On 2017-04-26 by (mod) - "actuator" is an electro-mechanical device, usually operated by an electrical relay

C:

An "actuator" is an electro-mechanical device, usually operated by an electrical relay that moves a lever or control arm to do something: open or close an air baffle, turn a motor on or off, etc. If the actuator is failing an early sign might be buzzing or, depending on the mechanical details of the device, vibration or even clanks and thunks.

In air conditioning system (HVAC systems) an "actuator" is used to open or close dampers (little doors) in the HVAC duct work to manage the flow of conditioned air. Examples of both manual and automatic or electrically operated actuators that open and close ductwork airflow are at ZONE DAMPER CONTROLS - https://inspectapedia.com/heat/Ductwork_Zone_Dampers.php

If the "actuator" on your hvac system is defective your tech ought to be able to

1. show you the devicve

2. demonstrate its noise or mechanical damage during operation

3. have the patience to explain those to you

On 2017-04-26 0 by C What is a "noisy actuator" i

- service rep recommended changing it, > $200.

What is a "noisy actuator" in an HVAC system? Is it a mechanical problem? I don't hear anything. Service rep recommended it. Thanks.

On 2016-12-10 by (mod) - When Trane unit cuts on it sounds like an explosion in a barrel.

Dixie

Perhaps if you have a friendly chat with the service manager at the service company you use, she can send an experienced service tech to help diagnose the trouble.

Did your repair person check current draw to see if there were signs of a failing compressor motor?

On 2016-12-09 by Dixie - lights dim in the house

When Trane unit cuts on it sounds like an explosion in a barrel. Did this several times and then runs and heats fine.

Now, it cuts on and off and runs a while and then starts cutting off and on every few minutes.

This causes the lights in my house to dim. The fan blows and the heat is fine, however , I have cut the unit off until
I can get it repaired. My serviceman is somewhat unsure of solution.

On 2016-09-06 by (mod) - an intermittent 'shhh' sound inside at the furnace.

Steven you can use the page top or bottom CONTACT link to send us sound recordings, photos, etc. for comment.

You may be hearing a pressure release safety device in which case the AC system is not working properly and is at an over-pressure condition.
If it were a perforated refrigerant line or coil the shhh sound would be a one time event as the refrigerant would be soon gone (into and unfortunately contaminating the atmosphere)

On 2016-09-05 2 by Steven

My ac unit, when on is making an intermittent 'shhh' sound inside at the furnace. It's like the sound you would hear when you turn the water to your home back on after returning from a vacation. I recorded the sound but unsure how to get it to you. Any ideas. Please email. Stevenfingold@hotmail.com

On 2015-09-02 by (mod) - whistling sounds

Dara:

Usually whistling is air movement through or over a duct leak, less often over an obstruction in the ducts.

A change in air velocity can make noises show up, such as when there is a dirty air filter or when the filter has been left off or when a blower unit door has been left open.

On 2015-09-02 by Dara

Two days ago, when my AC turned on, it had a strange whistling/ raspy noise. I have taped the noise but not sure how I can upload it to share with you.

I had a pretty dirty filter that I changed, but the noise has not abated at all. When we opened up the system, the fan motor appears to be working normally.

I did confirm this morning that fan only makes same noise as AC, so its the fan not the AC that's causing the ruckus.

Any help you can provide would be most welcome. I am currently out of work, so really need to know if this is dangerous/ could make the matter worse by using or just annoying. Thank you!

...

Continue reading at NOISES, HVAC SOUND RECORDINGS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES. or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see this

Article Series Contents

• HVAC SYSTEM NOISE DIAGNOSIS
  • CHATTERING RELAYS, HVAC EQUIPMENT
  • DUCT SYSTEM NOISES
  • DUCT VIBRATION DAMPENERS
  • FAN NOISES, HVAC
  • HVAC SOUND DESCRIPTIONS
  • HVAC NOISE-1 BANG BUZZ VIBRATE - banging, bearings, buzzing
  • HVAC NOISE-2 CHATTER CLANK FAN GROAN - chattering, clanks, clunks, cyclical, fan, groans, growls, honking
  • HVAC NOISE-3 HISS HOWL HUFF HUM - hiss, howl, huff, hum, groan, woo wuu wuff
  • HVAC NOISE-4 POP, RATTLE, ROAR, RUMBLE - loud start, pop, rattle, rumble, water, silence
  • HVAC NOISE-5 SCREAM SING TRUMPET WHINE WUWU - scream, sing, squeal, trumpet, wawa, wowo, water gurge, whine, whistle, wuwu
  • NOISES, HVAC SOUND RECORDINGS
  • REFRIGERANT PIPING GURGLING

Suggested citation for this web page

NOISES, HVAC SOUND RECORDING FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING NOISE DIAGNOSIS

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