How to Find Leak & Lessen Compressor Noise?

3/16/2021

I live in a 28-unit condominium with a dry system that we agreed to have the valve & compressor replaced in September 2020. The previous system's air compressor ran 2 times every 24 hrs for 16 mins. The new air compressor ran every 4 minutes for 8 seconds & was very loud in an enclosed room. This new air compressor quit after 90 days & breaking at 2 separate times on the copper lines.

How can we cut down the noise and make repairs?

As of today (March 2021), we have had a Cobalt compressor running in place of the general compressor that quit. The Cobalt runs every 70 minutes for 2.5 minutes. We are constantly told by contractor we have a leak somewhere that needs to be addressed, that we don’t doubt. We have cut the air off for a leak check, 2.5 hrs 2 lbs down.

I know this lengthy but I need some advice how to cut down noise and repairs. Thanks for any help.

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6 Comments

Dan Wilder

3/16/2021 08:06:45 am

First address the leak...no leak = less compressor time running.

Get some "Mega Bubble" and apply to every fitting in the riser room that contains air. We typically see issues at unions, the first fitting off the compressor, or the last fitting into the valve. You may have leaks in the system but lets tackle the easy parts first.

Get the system tested....mint-peppermint/pine-sol/eucalyptus oil will all be useful to locate a pesky leak in an attic. Possibly try to break the system up into sections via any low point/aux drains and test individually* (continue to hit those exposed joints with Mega Bubble).

There may be corrosion issues occurring (pin hole leaks for example) and that is a whole 'nother path of solutions.

Hopefully, the leak is addressed, now the compressor. General Air has a "Q Series" compressor that may be useful. Using high density rubber sound insulators at the metal/metal or metal/concrete mounting points and a flexible braided hose will also help a lot with noise transfer. Try not to mount the compressor to the riser without insulation (ever talk into a cardboard tube?) as it will just amplify the resonance of the large, empty piping network. Tank mounted compressors will also be useful.

*While work on the compressor, air piping and sound insulation may be in a maintenance person's wheel house, the wording of the post suggests you may not be in fire protection. I strongly recommend a licensed fire sprinkler contractor to address and solve these issues. If you would like some suggestions, let me know and I'll drop my email. My company has branches across the US & Canada.

Brian Gerdwagen FPE

3/16/2021 09:34:26 am

I have used this device in the past. It works fantastically:

https://www.fluke.com/en-us/product/industrial-imaging/sonic-industrial-imager-ii900

So easy and precise to find air leaks.

Martin J. Moffitt link

3/16/2021 11:28:16 am

That's a nice very piece of equipment!!! (PROFESSIONAL!) to the tune of 15k plus....
But, If that is a tool that gets you to the source of the problem quickly and efficently and you do this on a regular basis it's well worth the investment...It's the business of doing businness .going back to time is money!!..and getting it right the first time!
Some problems are best left to the pros and or someone well veresed in these kinds of situations ! Good luck

CJ Bonczyk

3/16/2021 09:58:16 am

I second Dan's recommendations regarding addressing the leak. If that continues to be ignored your will need to buy stock in compressor manufacturers. Additionally, the air compressor must be properly sized for the system installed as well so that it does not struggle trying to maintain any residual pressure loss. I have seen air compressors connected to an air reserve tank to help limit that amount of time the compressor cycles. Depending on the size of the system if its up to 300 gallons at 40 psi you can go with a the Gast model riser mount below. If you have a low pressure dry pipe system this compressor can handle a bit more volume. This will be at 63 dB, and you can add another sound kit for it to reduce the dB up to 25% more which makes it the quietest on the market.

https://gastmfg.com/products/87R/87R-110S

http://shop.gastmfg.com/ssp-87r6-01-sound-shield-87r-twin-pressure-non-biased-valve-kit/

However without knowing what the compressor feeds and how big the system size is its difficult to say if this model will work in your application.

Just to reiterate what Dan stated above, if you are a owner of the facility, it is strongly recommend you have a licensed Fire Protection Engineer or fire sprinkler contractor look at the system and evaluate what is the best means to mitigate the issue.

Aaron

3/16/2021 10:41:49 am

Ultrasonic leak detector.

Felipe Pedraza

3/16/2021 11:00:01 am

I also agree with Mr. Wilder. Address the leak first. Compressor shouldn't be running that much. Look at the simple area using soap and water and look for it. If that does not work, hydro test the system using scented solution that will aid you in find the leak. Once you find the leak and the problem continues after a period of time check the system for internal pipe damage. The pipes may be getting corrosion and causing small leaks to occur.

This happened to is in a Lowe's store. Leaks would get repaired in a the dry system and several months later, we responed to a fire pump running, and find another leak.

How to Find Leak & Lessen Compressor Noise?

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