finding a leak in 11 display cases all conected

[tsounos]

HI GUYS IAM NEW TO THIS FORUM.
IAM A REFRIGERATION CONTRACTOR WORKING MOSTLY
ON COMMERCIAL REFRIGERATION, IHAVE GOT A JOB IN A
SUPER MARKET TAKING CARE THEIR EQUIPMENT.
THERE ARE THREE COPELAND COMPRESSORS CONECTED IN PARALLEL.
THEY HAVE ACOMON CONDENCER,AND THEY ARE FEADING 11 DISPLAY CASES AND A WALK IN COOLER ,
ALL WITH THEIR OWN TEV THERMOSTAT AND SOLENOID VALVE. NOW WITH MY PROBLEM, IAM PUTING
ABOUT 45 KGS OF R404 EVERY 3 MONTHS. IHAVE TRIED TO FIND THE LEAK WITH ELECTRONIC LEAK DETECTOR, IN THE COMPRESSOR COMPARTMENT,AND CONDENCER, UNFOTUNATELY IHAD NO SUCCES FINDING THE LEAK.WHAT IS THE BEST METHOD FINDING LEAKS IN THESE BIG SYSTEMS, PLEASE GUYS INEED HELP ??????

[taz24]

.WHAT IS THE BEST METHOD FINDING LEAKS IN THESE BIG SYSTEMS, PLEASE GUYS INEED HELP ??????

Hello.

First leak test the air off ducts of all the cases. Leak test genral area around all cases / coldroom.
If you do not find anything turn the compressors off for ten or fifteen mins. Let the pressure build up in the systems and then leak test again.
Keep checking your leak detector against a known source of refrigerant to proove it is working.
If you still can't find it you will have to consider going into all the cases / cold rooms and check the TEV's individualy.
Check for oil in the drain water because this can be agood indicator.

Good luck
taz.

[US Iceman]

taz24 has some good ideas. If we separate your system into three basic areas it may be easier to find the source of the leaks.

1. One area is around the compressors, condensers, and relief valves. Look at each one of these as a potential leak source. Oil stains usually indicate a small leak. Be sure to check the relief valve outlets or their vent piping.
2. Display cases. As taz24 mentioned use your detector in the discharge air grilles. On glass door cases your detector might pick up the leak faster than an open display case. If the leak is in this area, it is probably due to the liquid line flare nut. Also, you may want to leak check the display cases and cooler when they are in defrost. Or as taz24 said, raise the suction pressure by shutting off the compressors for a short period of time.
3. If the leak is not in one of the first two examples, it is probably in the piping between the compressors and the display cases. If this is so, then it may be more difficult repair depending on how the piping was installed.

If soft solder was used any joint is suspect for leaks.

[taz24]

One area is around the compressors, condensers, and relief valves. Look at each one of these as a potential leak source. Oil stains usually indicate a small leak. Be sure to check the relief valve outlets or their vent piping.

Relief valves is a good one to check, they can become weak and vent early or just weep.
I put kids balloons over the end of the vent pipe or the valve itself if easier.
This will indicate if the vent / bleed or not.

taz.

[US Iceman]

I put kids balloons over the end of the vent pipe or the valve itself if easier.

I know a guy who said he likes to use condoms over the relief valves.

I'm not sure if that was all he could find, or if he liked to see them blow-up.

[taz24]

I know a guy who said he likes to use condoms over the relief valves.

I'm not sure if that was all he could find, or if he liked to see them blow-up.

I thought of them but how do you explain them in you toolbox

taz

[US Iceman]

I thought of them but how do you explain them in you toolbox

Well (he says now with a straight face), if they were the lubricated type then I think you might have some explaining to do.

[taz24]

Well (he says now with a straight face), if they were the lubricated type then I think you might have some explaining to do.

LOL

taz.

[NH3LVR]

I know a guy who said he likes to use condoms over the relief valves.

Used to do this myself with the cheap aluminum valves found on many screw compressors.
Proof positive of a leak.
(But it was a Little hard to explain when someone walked by the engine room)
I did not, however turn in the receipt for reimbursement.

[US Iceman]

I did not, however turn in the receipt for reimbursement.

I'm sure the bookkeeper might have looked at you strangely for trying to charge these off to a job.

Then again, I was always told discretion is pricless. So you were right to not list it on your expenses.

They would be much more difficult to explain to a jealous wife though.

[Temprite]

HI GUYS IAM NEW TO THIS FORUM.
IAM A REFRIGERATION CONTRACTOR WORKING MOSTLY
ON COMMERCIAL REFRIGERATION, IHAVE GOT A JOB IN A
SUPER MARKET TAKING CARE THEIR EQUIPMENT.
THERE ARE THREE COPELAND COMPRESSORS CONECTED IN PARALLEL.
THEY HAVE ACOMON CONDENCER,AND THEY ARE FEADING 11 DISPLAY CASES AND A WALK IN COOLER ,
ALL WITH THEIR OWN TEV THERMOSTAT AND SOLENOID VALVE. NOW WITH MY PROBLEM, IAM PUTING
ABOUT 45 KGS OF R404 EVERY 3 MONTHS. IHAVE TRIED TO FIND THE LEAK WITH ELECTRONIC LEAK DETECTOR, IN THE COMPRESSOR COMPARTMENT,AND CONDENCER, UNFOTUNATELY IHAD NO SUCCES FINDING THE LEAK.WHAT IS THE BEST METHOD FINDING LEAKS IN THESE BIG SYSTEMS, PLEASE GUYS INEED HELP ??????

Hello.

What kind of leak detector are you using?

[tsounos]

Thanks Guys For Your Information.
I Was Thinking To Insert Red Die ,or To Use The Floresant Light With The Chemicals .
But Its A Pain Of The Neck ,and The Costomer Is Very Cheap He Does Not Whant To Pay.
Much.also The Display Cases Are Stocked With Products.
Also Ilooked To Find Relief Valves I Could Find Them. I Think They Are Usualy On The Receiver.

[tsounos]

Hi Temprite Iam Using An Electronic Leak
Detector That Ihad Previously Used And Ihad Great Resaults, But In Single Refrigeration Units.need Ideas????????////

[taz24]

Also Ilooked To Find Relief Valves I Could Find Them. I Think They Are Usualy On The Receiver.

A single conensing unit of this nature may not have a relief valve.
If old enough it may have a fusible plug.

taz.

[saud khan]

hi iam sure there are colour die which you can put in the system which show up when ultra violet light is shown on it it will stand out like a sour tum , only thing is the kit is not cheap
saud

[tsounos]

Thanks Again To All Of You , I Will Lets You Know How It Came Out. Maybe Iam Getting Old For That Kind Of Things,
When I Was 20 Icould Spand Many Hours On A Single Equipment Until I Fixed To Perfection.

[Lowrider]

Also check the evaperators! Just had a job on a downcooler which had been recharged several times by colleges of mine. They never found the leak! Pressured it with nitrogen to 30 bars and could hear a little hiss in the evap! Took it out and found multiple small holes from corrosion!

Be sure to check with the company who manufactured the compressors because most don't like you putting in anything due to possible reaction with oil and other components!

Buy a good electronic leakseaker for the right refrigiranttype and test all joints!

Relief valves, at least in Holland, are demanded in system with more then 100kg of refrigarant of if any compressor has a higher strokevolume than 90 cubicmetres/hour!

I'll remenber the condoms! Nice one! See what the gay-guy at our administration has to say when i turn in the bill!!!!

[Peter_1]

I thought of them but how do you explain them in you toolbox

taz

Oohhhh, are condoms then not for in your toolbox?

[Peter_1]

45 kg in 3 months... a good electronic leak searcher must find this leak.
According to the EU laws, you must find the leak and repair it, not just refilling.
And indeed, it can take some time.
Said already by Taz and some others, check TEV's, SV's, check for oil in the drain pan (this is what I also do Taz),

The leak can be hidden in ice (TEV's for example)
The UV dye is for the cars, not for professional work.

Go once early in the morning so that you can open some displays, especially around the TEV.

You don't see a greasy corner in the condensor?

[Gary]

Before checking each display case and it's piping, put the case in defrost in order to raise it's pressure.

If the system has a heat reclaim loop, be sure to check this also.

Worst case scenario: It may be necessary to pump down and cut liquid and suction lines to each case and pressurize the loop (suction line, liquid line and evaporator) to 250-300 psi with nitrogen for a couple hours, in order to identify which loop is losing pressure (leaking).

[Rubba]

i have recently had a memo from my company warning us of defect danfoss valves on all applications under 4 years-should be ok as long as the valve cap is kept on and tight!also it wouldnt be the first time an engineer has screwed the back panel and pierced the evaps either, happy hunting!

[750 Valve]

Danfoss ball valves (the allen key ones) leak like a sieve!

[Cofreth]

Anyone tried refrigerant oil color dye, it works.

[taz24]

Anyone tried refrigerant oil color dye, it works.

Yes and it also messes up your system

I dont like adding dyes to fridge systems.

taz.

[Cofreth]

Yes and it also messes up your system

I dont like adding dyes to fridge systems.

taz.

Guess that is the only way to check for leak without effecting the operation of the entire refrigeration system.

[taz24]

Guess that is the only way to check for leak without effecting the operation of the entire refrigeration system.

If you do it right you can find any leak without haveing to add chemicals to the system that wer'nt meant to be there.

A systematic leak check will do the trick.

Dye's won't find leaks inside the cases.
You removeing stock and going into the case will find the leak dye or not.
So if you have to pull things apart to see the dye why not just pull it apart and leak test it.

taz.

[Cofreth]

If you do it right you can find any leak without haveing to add chemicals to the system that wer'nt meant to be there.

A systematic leak check will do the trick.

Dye's won't find leaks inside the cases.
You removeing stock and going into the case will find the leak dye or not.
So if you have to pull things apart to see the dye why not just pull it apart and leak test it.

taz.

If you are doing it one unit at a time,how are you going to achieve a higher pressure for a quick leak test without shutting the entire system.

[taz24]

If you are doing it one unit at a time,how are you going to achieve a higher pressure for a quick leak test without shutting the entire system.

If it was me I would turn off the comps and let the pressure build up. I would leave it for a while the stock won't know for a good few hours so thats not an issue.
Then leak test the air offs.
With a good leak detector you will find even the smallest of leaks.
Put the leak detector probe in the bottom of the case through the air return grills.
You will find the leak if it is there even a small one.
Leak test all the floors under the case's and the case tops.
If done corectly I garentee the leak will be found.
He is looking for a leak on one condensing unit and elleven cases.
It is not a large system.
Experience will come into it.
Find the oil and you find the leak, also it may not be one leak it could be numerous little ones.

Just my two peneth worth

taz.

[taz24]

If you are doing it one unit at a time,how are you going to achieve a higher pressure for a quick leak test without shutting the entire system.

If you introduce heat into the system the back pressure will rise even higher.
Force the cases onto defrost as you leak test and the back pressure will rise.

New dyetells are good but I do not like adding things to systems if I can avoid it.
I have seen countless complications when the stuff has been used.
Not just one brand I'm talking of most brands over years and years of use.

Cheers taz.

[smilies]

No dye in racks, period. Thank you for your time.

[Peter_1]

Smilies, no need to shout but why shouldn't you. You don't give an explanation.

[willee10]

you can get dye for a resaonable price but I dont like the stuff myself, make sure your electronic is picking up R404 firstly, you have got a good sized leak there it must be costing the customer a boom and questions are going to be asked, I find using leak spray,torch and mirror and alot of patience the best was find those hard to find leaks.start from the disharge and follow the pipe work until find ,good luck.

[750 Valve]

No dye in racks, period. Thank you for your time.

Copy that!
11 cases is NOT THAT MUCH, the only application dyes are good is secondary circuits (glycol), am contemplating/investigating use with r744 as traditional leak detectors aren't really available, more personal air meters, plus when it leaks it forms ice, when it works it forms ice (gotta look for different types of ice!) and got about 75 cases to leak test over 44 sets of mains

[smilies]

Smilies, no need to shout

No, I do have to shout it. Salesmen and junior techs are pushing this as a solve-all for leaks. Besides ruining every gauge hooked up to it, it's just not good practice. It's another possible contamination of the system.

but why shouldn't you. You don't give an explanation.

Didn't your instructor ever tell you that only two things belong in a system? Oil and refrigerant. As another poster said, with dye you are gonna have to remove some shelving and product to find the 'mark'. Why not do it right and cleanly with a good leak detector. I myself use an H-10G or an H10PM, and if i have to, my old TIF. Some good practices have been suggested already.
Look, finding leaks can be a pain the ass, but with patience and maybe another fresh head, it can be found. My worst was adding 100 pounds every month for 8 months until we found it----2 o'clock side of insulated suction line in overhead, above the magazine area, 35 feet up.

[smilies]

Also, as a contractor, verify with whoever runs the show for that particular customer that adding dye is an option. It may not fly with them if they are somewhat knowledgeable about their refrigeration systems. It also covers your butt in the future.

[Peter_1]

Didn't your instructor ever tell you that only two things belong in a system? Oil and refrigerant.

Apparently, you're only a member of this forum for some months and I will forgive you.

Have I ever said that dye belongs in the system? You're making to fast conclusions and you're making statements without explaining them.

'My instructor' you said. Well, I will have to think twice before I answer this one

[smilies]

Apparently, you're only a member of this forum for some months and I will forgive you.

Thank you, I need all the forgiveness I can get.

[wineman]

what i can tell you putting refrigerant in with out finding a leak is illegal and you could be prosecuted because youare knowinly venting refrigerants to the atmosphere ps try a leak dye

[Peter_1]

Here we go again: pro-dye, contra-dye...??
You see Smilies, the answer is not always that easy.
Legislation plays also a role here.

[US Iceman]

My worst was adding 100 pounds every month for 8 months until we found it...

You need to know this could be considered a willful violation of the EPA rules. The fines for for this type of a violation are around $33,000 per day.

You should look for a guidebook titled "Compliance Guidance for Industrial Process Refrigeration Leak Repair Regulations Under Section 608 of the Clean Air Act".

This document tells you specifically how much time you have to repair a leak. I'm not sure why they called it Industrial Process Refrigeration, but go figure... It's a federal piece of work.

[Peter_1]

I think this was something the instructor forgot to learn his students

[US Iceman]

I think this was something the instructor forgot to learn his students

I don't think very many people know about this. It would be bad if they learned about it from an EPA inspector.

[smilies]

I believe it could be construed that way. The legal team for that company at that time believed us to be making a concerted effort to find and repair refrigerant leaks. The follow up process was not a very good one as it is a large company, but I know they have tightened up their dispatching.

[smilies]

Also, USIceman, I haven't read that article. Is it also broken down into Commercial Refrigeration and Comfort Air Conditioning? I believe Commercial and Industrial are at the 35% per year mark and AC at 15%. Am I right, or should I pick up a manual?

[US Iceman]

Here are some links for some night time reading...

http://www.plantops.umich.edu/PlantE...2002-09/8.html

http://www.environmental-expert.com/...type=6&level=0

http://www.environmental-expert.com/...type=6&level=0

http://www.environmental-expert.com/...type=6&level=0

http://www.environmental-expert.com/...type=6&level=0

And the first document I referenced can be found at this link.

http://www.refrigerants.dupont.com/S...egulatory.html

Look for "Refrigerant Management" at the bottom of the page.

P.S. It is not an article, it is a compliance guideline for meeting the intent of the regulations.

[750 Valve]

Not always as simple as ya can't find a leak so ya cop a fine for topping up...
Often these things are cost related, outcomes often driven by regional maintenance managers, OH and S reasons or things out of your control (like your boss). I'm happy to throw in gas if the site will not co-operate, its not my call, as long as I do my utmost to find the leak in the conditions present. I think you'll find that if you leak test - honestly giving it a shot and the manager/owner will not allow plant to be shutdown or further leak testing other than pissing in the wind then its HIS fine not anyone else's... THEY are not addressing the issue, nothing to do with me, although I AM a FRIDGIE, I'm only human and not dying for anybody's stock to stay cold.
Too many people making claims like this work on smallish single system evaporators (Not you iceman I know you do bigger gear) where the hardest pipework to access is above the room or the 2 door underbench they just got unloaded... PLEASE! Put em in an industrial plant or supermarket with a kilometer of pipe and a leak detector..... Lets see ya find it first time bigshot - keep in mind food over 5 degrees C will be thrown out and your boss will get the bill, ya can't turn the system off coz production is already low this month and the fat useless site engineer is still whinging about the last bill...
Lets get rational here, its NOT my gas, its NOT my coldroom and its NOT my leak. Yes I have been entrusted to repair the system for the owner, but it is still HIS plant, all major decisions about the plant should go through him, put the ball in his court, make it his problem if he won't let you leak test safely.
Don't get me wrong I'm not discriminating against smaller systems (or their mechanics ) I love all fridges big or small but think that this issue is not black and white, it just gets me when blokes start sprouting in very general terms, its a very diverse industry, practices applicable to one facet may not necessarily ring true across the board.

[Dan]

There is another way, although I am still laughing about the condoms. Turn everything off and listen. If you are in the machine room, turn everything off and put your ear to things. I use an ultrasonic detector in addition to my electronic. If you are wanting to check some cases, turn the fans off and listen. If you are using an HFC refrigerant, your electronic might not be registering well.

Look and listen. I have have techs who couldn't find a blower with a leak detector, but found it in the overhead with a flashlight, seeing a ball of ice. Your leak is perhaps smaller, but I bet you that you can hear it if you make the extraneous noise go away.

[US Iceman]

Some good comments coming out of this. Let's stand back and look at practical approaches too. Look for oil stains or areas where a component or section of pipe is fuzzy. Wipe it off, if it is oily it is leaking.

Most of these troubles can be solved or found if you know what to look for.

One firm called me a coupe of years ago to help find a leak. Hundreds of pounds of refrigerant added every year. No one could find the leak, which I think was an excuse for laziness or not knowing what to look for.

After 20 minutes I found about a dozen oil stains which were fuzzy from collecting dirt. I told the owner to have his contractor start by checking those.

2 weeks later all of the leaks were miraculously found and repaired. please, this is not that hard. If you want a challenge find a leak on a supermarket system or a BIG refrigeration system.

PS. All of the leaks were on the rack system around the compressor and regulating valves.

[lana]

Dear tsounos,

Have you found the leak?

We are waiting for the result.

Keep us posted.
Cheers

[Sledge]

I am still at the "to dye or not to dye" part of this discussion.

I have been back at this business for almost a year now, after a 10 year absence. I am currently doing rinky dinky little stuff these days ( all my contacts disappeared in industry, while I was doing my walk-about) but back in the late 80's and 90's I put dye into everything I worked on, and made leak check with a lamp part of my pm programs. I ran my business from 87-95 and kept most of the major accounts for the duration (closing business due to marital breakdown, not due to business loss). I didnt encounter any issues from dye.

What are the issues caused by adding dye?