Would anybody have any good ideas other than pressure testing, and using soapy water to find LEAKS... R407c? Any ideas..
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Would anybody have any good ideas other than pressure testing, and using soapy water to find LEAKS... R407c? Any ideas..
Electronic leak detector!
Had one before but found these sometimes unreliable..
Hi, Thana :)
...sorry do not have any, butQuote:
Originally Posted by Thana
....:confused: what is your idea instead of pressure testing :confused: for leak test of system working under some pressure...
...whichever refrigerant we use.... it is too expensive... first to charge the system and then looking for leaks:eek:
OFN is not too expensive and just need some more time to check all with soapy water...
Maybe I am not right:confused:, maybe there are some new technologies which I do not know...
Best regards, Josip :)
Just a thought but Vulcan Lockring had a leak detector on display at the last RAC show i went to that was used with a nitrogen mixture that i think contained helium. They demonstrated it using a ballon.
Has any one used it?
It seemed like a good idea at the time but i have not heard any more about it.
They are pretty reliable these days, question is how are they used. If you using them in strong air flow, and with saturated tip (sensing tip need frequent change) they are almost useless.Quote:
Originally Posted by Thana
Try to find this:
http://tinyurl.com/2pe6gc
I only hear good comments about these.
And this is from Bacharach site:
Methods of Refrigerant Leak Detection
One of the most difficult areas of sealed system servicing can be trying to find a refrigerant leak. The leak may exist within a series of tubing that may be up to hundreds of feet long or in a component that is not readily accessible or may even be, totally concealed. It could be in an operating or safety control such as a pressure switch or possibly right under your nose and you wouldn’t even suspect it. As we all know, refrigerant leak detection can sometimes be a serviceman’s nightmare.
Having the proper test equipment is at least half of the battle. Unfortunately there are so many methods of leak detection and so many types of test equipment and unfortunately, not just one fits every situation. Decisions need to be made as to the method used and the type of equipment needed for every leak you need to find.
The sole purpose of this section is to help make you aware of the different methods available and to help you decide on which method is most appropriate to use in different situations.
All of these conditions make leak testing one of the most challenging tasks faced by service technicians today. The newer EPA rules are now requiring service technicians to find leaks that are excessive of the law, thus not allowing technicians the choice of just adding refrigerants every so often to keep the system in operation. Add to this the cost of refrigerants today and it become imperative that refrigerant leaks must now be found.
As you know, there are several methods used to find leaks. Some of the most popular are methods are listed below. They are not in any particular order because each leak is unique to the situation at large.
Bubble Test (Soap Solution)
A soap solution can be used when you know the approximate area where a leak may exist because of sealed service repair recently done or an electronic leak detector has indicated a leak exists in a particular area of the sealed system.
For example, if you repaired a leak, or replaced a component, or know that a system has a leak somewhere and/or you observe an area of the system that is oil coated, you would probably use a soap solution, in that area, to test for and pinpoint a leak. It is the simplest and least expensive (material wise) method known today. It may however be more expensive to use, because of labor costs, if the technician does not have any idea where the leak could be.
Soap solutions are available in many different types. Some have a brush applicator and others have a dabber (an absorbent ball attached to a stiff wire inside of the cap.) Some brands may even have a spray applicator to quickly cover large areas of tubing in a short amount of time. This is an advantage but is also messy and time consuming to clean up.
Some soap solutions even have an antifreeze base to prevent them from freezing in the winter time. Others may have a lower density to make them even more sensitive to very tiny leaks.
Some pointers when using soap solution:
If the system does not contain sufficient pressure for leak detection, the refrigerant can be recovered from the system and the system re-pressurized with dry nitrogen to increase the pressure, making it more a probable and less time consuming way of pin-pointing the leak.
WARNING:
Do not pressurize the system or component to be checked, more than the manufactures leak testing standards. This pressure is usually stated on the name plate as factory test pressures. If it is not stated on the nameplate, a safe pressure is usually less than 150 psig.
There may be times in which an oil spot is noticed in an area of the sealed system. This is usually a suspect that a refrigerant leak is present in that area. A soap solution can help to pin-point the leak.
A pointer:
Holding the dabber against the suspected leak for a period of time may provide better results for small leaks.
Water Immersion Method
This method can only be used if the system is small enough to be emerged in a tank of water or if the suspected leak exists in a component that can be cut from the system, sealed and pressurized with a high pressure, dry nitrogen charge. That system or component of the system is then submerged into a water tank. Then the technician watches for bubbles escaping from the leak.
Some pointers when using the submersion method:
A detergent can be added to the water to decrease surface tension, which helps to prevent the leaking gas from clinging to the side of the component.
Hot water in the tank sometimes helps to increase the pressure inside the component or piping system. If dry nitrogen is used, this does not help because nitrogen does not increase significantly. If refrigerant is contained in the system or component, it may help considerably to increase the pressure and increase the chance of finding the leak.
Halide Torch
A halide torch is an inexpensive leak detector that is fast and reliable, but can only be used to detect chlorinated refrigerants. It can be used to detect leaks as small as ½ ounce per year.
A halide torch works on the principle that air is drawn over a copper element heated by a hydrocarbon fuel. If halogenated refrigerant vapors are present, the flame changes from a blue pictures of halide torch color to a bluish green color.
It is not as sensitive as electronic leak detectors and is somewhat awkward and could be dangerous because of the open flame.
Dye Interception Method
This is method in which a dye is inserted into the system in hopes that some day, the leak allows the escape of a colored dye where the leak exists. This dye becomes visible after a period of time, notifying the technician where the leak is.
Ultraviolet leak detection dyes are also available. These dye kits sometime requires more expensive equipment to detect the leak. This may include an ultraviolet lamp, ultraviolet dye, and some method of getting the dye into the system without letting any moisture or air into the system. These dye methods may be more time consuming because of the time it takes to leak the dye and be visible to the human eye.
Some considerations when using a dye might be:
The dye may be considered a contaminate to the sealed system and is difficult to get into the system without moisture contamination. Even the slightest bit of moisture is detrimental to the longevity of any sealed system.
This method can be (and usually is) a mess and normally requires some type of clean up. The dye usually ends up in your test equipment (gauge manifold and/or refrigerant hoses) and is usually a time consuming mess to clean up.
This method is usually time consuming because it could take several hours or days for the dye to leak from the leak source indicating a leak. This method also means you have to have access to all of the system, which may limit its use.
Standing Hold Test
This method consists of pressurizing the system with a high pressure, dry nitrogen gas. A pressure, usually between 100 to 200 psig, for a period of time and then identify whether or not the pressure drops during this time. The higher the pressure, the faster you can determine if a leak is present. Fortunately, dry nitrogen experiences very little pressure changes when it is exposed to small temperature changes.
WARNING:
Do not pressure the system or component, to be checked, more than the manufactures leak testing standards. This pressure is sometimes stated on the nameplate as test pressures but if not, using less than 150 psig is usually safe.
The disadvantage of this method of leak detection is that it can only be used if you have a system that can be shut down for a period of time (usually overnight or longer.) This can be time very consuming because some low-level leaks may require a holding period of up to 48 hours or more. It’s not that you have to stay with the system for that period of time, it’s just the fact that the system may need to be out of operation for that amount of time.
The advantage however is that this method will positively identify whether or not a leak exists by monitoring pressure drop. If any pressure drop occurs, it means a leak is definitely present. The disadvantage: This method does not identify where the leak exists, only if a leak is or is not present.
Isolation of the Sealed System
This is a time consuming method of the standing hold test but is sometimes your only choice. It is usually used when you have no physical access to components in which you suspect are leaking or when you want to identify which part of the system contains the leak. Some examples might be: a concealed refrigerant line, an in-wall condenser, an in-wall evaporator, or any component in which you do not have access to.
This process would include isolation of the component (suspected of leaking) from the rest of the system. This is done by breaking that part of the system apart from the rest of system, sealing it, and pressurizing only that component with dry nitrogen. Then use the standing hold test covered before. If the system’s pressure drops fast, there is a large leak present in that component or section of the system. If the system’s pressure drops slowly, there is a small leak present. If the pressure remains the same, that component does not leak.
This method can limit your leak detection labor time only if the system can be out of order for a period of time. Once the component leaking is identified, determine if repairs can be made or not. If not, that particular component can be replaced if it at all possible.
A process tube adapter kit could save you some time. It can be quickly connected to the part of the system that has been cut out. This eliminates having to make a mechanical or brazed connection.
Electronic Leak Detectors
Using an electronic leak detector is generally the fastest way to find an unknown leak.
They can be used to quickly find a leak, or to find the area in which the leak exists, in a sealed system when you don’t even know where to start. An electronic leak detector gets you real close to the leak. After you find the area in which the leak is detected, you can usually decrease the sensitivity of the some types of detectors to pin point the area of the leak. The leak area is then coated with soap solution to verify the exact point of the leak.
Electronic leak detectors must be designed to detect a certain type of or multiple types refrigerant, i.e. (CFC, HFC, HFCF, etc.)
Warning:
You must be careful because you can waste a lot of time if you’re using a detector that is not compatible with the refrigerant that is contained in the system you are leak testing.
Know your leak detector’s capabilities and also what it is not capable of detecting.
Carbon monoxide and alcohol can affect the sensitivity of most electronic leak detectors. Be sure neither is present when leak detecting.
Operation usually depends on a variation of current flow caused by ionization of decomposed refrigerant between two oppositely charged platinum electrodes.
Important Warning: Most electronic leak detectors are not recommended to be used in atmospheres that contain flammable or explosive vapors. The sensor operates at an extremely high temperatures. If this sensor comes in contact with a combustible gas, an explosion will occur. This can be very dangerous and costly. It will probably ruin your electronic leak detector and/or possibly damage or destroy a building because of an explosion. Most manufactures will not honor warrantee products against abuse, and exposing a refrigerant sensor to combustible gases, constitutes abuse.
Some Pointers when using electronic leak detectors:
If the leak is suspected to be very small, it may be possible to enclose the suspected area for a period of time to allow the leaking refrigerant time to accumulate. When accumulated, it is then more readily sensed by the detector.
This may be done by:
Wrapping a suspected leak in cellophane and leaving it pressurized with a refrigerant charge for a period of time. Then using an electronic leak detector, cut the cellophane at the bottom while using an electronic detector to detect any refrigerant that may have accumulated in the pouch over time.
It is permissible to add a little vapor R-22 to a system and then re-pressurize the system to a higher pressure by adding nitrogen to the system containing the R-22 holding charge. This increases the chance of finding the leak and is considered, by the EPA, as “De Minimus Release” (a good faith effort of finding a leak that may prevent future refrigerant venting through a leak that is not found.)
If a refrigerant component or piping section that is suspected of leaking, is inside a compartment (such as a freezer/refrigerator compartment or a small room) and a leak is suspected in that part of the system. That section could be easily isolated by closing a door and trapping the components in an enclosed space. This space can be concealed for a period of time and then when re-entering the space with an electronic leak detector.
If the detectors alarm goes off, you have verified the leak exists in that component, tubing or area.
Again, re-pressurizing the system to a higher pressure and of course, having refrigerant in the system, will accelerate the process.
Refrigerant has a higher specific volume than air, therefore refrigerants will fall when exposed to atmospheric pressures. This means leak detecting on the bottom sides of the piping or components will be more effective in detecting a leak and will save you time.
Ultrasonic Leak Detectors
This type of leak detector is relatively new to our industry. It consists of a device that is capable of amplifying noise so the human ear can recognize very small noises. Most detectors will allow a technician to hear minute sounds such as a very small leak in a sealed system. This procedure can be very successful if, and only if, the area in which your trying to detect the leak in is ABSOLUTELY QUIET AREA. This is usually impossible, which imposes great limits on the ultrasonic leak detector.
As usual, the higher the pressure in the system, the greater the chance of finding or in this case, hearing the leak. It can be used in the same manor as an electronic leak detector with one exception. It is more effective using dry nitrogen as a pressure medium than refrigerant because nitrogen has a lower specific volume than refrigerant. This will permit the nitrogen to escape faster thus being more easily detected.
Thank nike 123, nice reading...I think I will endevour with the old soapy water method as this seems to be the cheapest method maybe perswade my boss for an electronic leak detector at some stage..
I bought a cheap elctronic one from ebay for $45 that works well, some made in china wj60000 or something like that. Didn't need to go overboard as I don't like any of them anyway, just needed one for a licence down here.
It's hard to find a leak at static pressure with an electronic detector, and here it's now illegal to bump up the pressure with nitrogen without reclaiming the trace gas and nitrogen mix. So electronic detector are now next to useless for hard to find leaks as I'm not going to reclaim and store a nitrgen/refrigerant mix.
Nitrogen and soapy water is best, just use a high pressure, like 2000-2500kpa, and isolate the system as much as you can using service valves.
If you have a bugger of a leak to find, shut and cap outdoor unit, plug up the flares going to it. Then use plugs and 1/4 flare shrader adapters on indoor units and interconnecting pipes. Pressurise them all individually and give them a good going over, even if you can't find the leak directly, you will find where the pressure drop is. Then spend more time taking that section apart etc
Paul,
It is lot of electronic leak detectors and results are varying allot. Also, one need lot of experience to work with them because they are so sensitive at lot different things along with refrigerants. Once you got right one and learn how to recognize false and right reaction than you find that they are pretty good in their job!
P.S. What happened with that Fujitsu we recently discussed?
It's expensive trying them all to get the right one though ;)
The one I have, a $45 cheapy does work, you're just limited by them due to wind, not being able to crawl up wall cavity with them, and low static pressures.
Leaks often occur at running condensing pressures, which you can't test a due to condenser fan draft. That's why I prefer 2500kpa+ in the system, and as I've mentioned, you can't use a refrigerant and nitrogen mix here anymore without reclaiming it. And I refuse to reclaim a system full of 2500+ kpa of nitrogen.
As far as the fujitsu, maybe ozairman will come back one day and let me know. He hasn't been back for a week and I quit that job on friday. I'm just not one to slack off even if I'm leaving, so I was trying to give them all the info I could get before I left. From what I learnt from you the fault was probably just the indoor thermistor fault. ozairman knows a fair but about those systems, so I guess he'll be on the case now.
Thana,
Vulkan produce a product called Loktrace this does not contain Helium and is a very cost effective alternative.
Loktrace is detected by a gas specific detector, the blend is a Nitrogen/Hydrogen mix that has been scientifically blended to keep it totally inert.
To date we have had many sucessful experiences and will shortly be going to press.
This product is manufactured as a complete kit in the UK and has a patent pending, if you require any further information please ask.:)
For general leak testing soapy water and electronic testers win hands down. For problem systems spectroline is good.
Infra red type from NRS is the best I have used well recommended!
Jayvac
I use a CPS LS3000 to locate a leak and to pinpoint the exact location I use Big Blu leak detection solution from Refrigeration Technologies. Works for me every time.
Cheers
Hi Thana:rolleyes:Quote:
Originally Posted by Thana
*You can dip ur system whether it is evaporator coil or condensor coil in water & identify leak,remember the system contain some pressure at that time.
Bubbles evolve woul give you leak points.
*You can use leak detecting torch.Find one in the market.
regards
Praveen:cool:
In agreement with NIKE123, the basics are getting in the ballpark with the electronic sniffer followed by some Big Blue bubbles. Process of elimination. Also service valves are known to leak if you have your flare connections.
Recover your 407c, put a fart of R22 in. Find leak with naked flame type detector. Recover R22, job's a good-un. Won't do any harm to your 407c system.Quote:
Originally Posted by Thana
Except that it is illegal to put refrigerant into a leaking system.
i use leak dye which seems to work well on hard to find leaks . or we get this stuff from usa in a can that u inject into system and works simular to rad weld for small leaks i think no more than 15% over two weeks
cirtenly if you use a torch,never now were the flame is going to!!!!!
ice
I'm with the big Blue and CPS crowd.
Just make sure you dry the pipe and fittings before you run the leak detector over it. if you get moisture in the sensor it will ruin your day.
The trick is to re zero the leak detector as you get closer to the leak to desensitize it. Makes pinpointing the leak a lot easier.
anyone using an ultrasonic leak detector?
Have used them in the past, present firm doesn't use them, and found them quite useful.Quote:
Originally Posted by Slatts
hi im new 2 this site .i have small leak in my ice cream machine think in barrel pipe but it got insulation all round it would a can of spray added 2 system stop leak 4 me
Probably not.
The only thing I'd put in a refrigeration system, particularly a small one like this, is refrigerant and oil.Quote:
Originally Posted by birdy7860
If you have a leak on the barrel, it's probably caused by corrosion. If you have one pin hole now, you can expect several more in the near future. either get a new barrel fitted or a new machine.
by the way, it might be good manners to start your own thread instead of hijacking someone elses.
electronic leak detectors and soap leak detectors dont mix i've had a lot of them that pick up the soap itself and many other things which makes them useless to me now. dye soap and nitrogen work best for me
thanks nike
since when is it illegal to put refrigerant into a leaking system? when you arrive at a job and there is no gas in system at all what are you supposed to do?
it is only illegal to add refrigerant to a system knowing that it is leaking and not having found a leak!
I carry a D-Tek electronic good for detecting 1/4oz. per year as per mfg. The problem is it is tempermental with blends like R134 and R404. Also found it will pick up around new rubber pipe insulation. Some companies used R22 as propellent in making material but the sniffer doesn't know it. Now I use u/v dye 95% of time. It has NEVER let me down. Just use as instructed. Too much is just a mess. One more thing...compressor mfg. here in U.S. will void warranty if a product called TRACE is found in returned body. It is red liquid and they claim it contaminates body. They all accept the u/v dye if needed. Good luck !!
If you cant locate the leak with bubbles do not waste any more time and get that thing pumped up 2800kpa if vessels alow it on name plates. isolate each section of the plant if possible and leave on drop test.
Yes Introduce Dye to the system, and then check with spectrum light the next time you return.
I remember my early days as an Aircraft Mechanic working the ***** systems on DC-8 aircraft (2 16 ton R22 units)The norm was soapy water. We had a vendor come in with a "new fangled" electronic detector; Not to say we had any trouble with leaks (it was typical to use 15lb per flight). The detector would "go off" as soon as he entered the building (still hundreds of feet away from the A/C).....Back to bubbles:)
:eek::eek:get up to speed , you are so breaking the law . :eek:Quote:
Originally Posted by coolhandlew
Can I assume that its ok to pressurize any R-22 A/C component to 250 psi?
If you leave a package unit outside, the vapor pressure of R-22 will each 265 psi at 120*F, which is easy to do in the sun.
Once the whole system is up to ambient, the whole system, including low side will be at the refrigerant's natural vapor pressure.
Reply to Ultrasonic Leak Detectors
This really depends on the detector you purchase. I had a desk full of "cheap" detectors. None of them worked for HVAC in power plant. I purchased the UL101 on a 30-day trial. After a few hours, I had to stop using it so I could fix all the leaks it found. Saves me hours!
I threw the box away and continue to use it for past several years. The price is not for everybody, but if you want a Ultrasonic Detector that works, well if you can afford it...
Ultrasonic Leak Detectors
This type of leak detector is relatively new to our industry. It consists of a device that is capable of amplifying noise so the human ear can recognize very small noises. Most detectors will allow a technician to hear minute sounds such as a very small leak in a sealed system. This procedure can be very successful if, and only if, the area in which your trying to detect the leak in is ABSOLUTELY QUIET AREA. This is usually impossible, which imposes great limits on the ultrasonic leak detector.
I have to disagree with Nike. You can use ultrasounds in noisy ambients. Normal sounds do not affect to the ultrasonic search. Normally, in noisy environments, there are also noisy ultrasounds which compete with the leak ultrasound we are looking for. The goal in these cases is to block the competitor ultrasounds, which is relatively easy, since ultrasounds have a short and weak sound wavelength.Quote:
Originally Posted by worldb
Regards,
Nando