advice regarding hard to find HVAC freon leak

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ProfessorX
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advice regarding hard to find HVAC freon leak

Post by ProfessorX » Mon May 19, 2014 3:42 pm

Hello,

I have a five year old new construction house with a leaky freon HVAC. (It uses the banned R-22 kind too.) Last year they filled up the freon and did a human inspection for leaks (with no high tech leak finders) for $350. This year the freon is about half empty and they want to do a pressure test with chemicals to see if there is a line set leak (i.e. a leak in the coolant line going through the walls of my house) and to definitively figure out which piece of the system is leaking. It would cost about $425. It takes a few days because it is an extremely slow leak so they have to come back days later to check the pressure levels.

Costs either go up astronomically or double astronomically after that depending upon what they discover to be the problem.

Anyone have experience with finding freon HVAC leaks? Should I do the pressure test? Any other potential courses of action that I currently may not know about?

Thanks!

EDIT: Also contacting the original installers etc is not an option. They are long gone unfortunately.

Calm Man
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Re: advice regarding hard to find HVAC freon leak

Post by Calm Man » Mon May 19, 2014 3:51 pm

Professor, I am worried about this "banned substance". Is it potentially harmful if leaking to you or others? Also, if the pressure test shows there is a leak, will it actually localize it or just confirm it? Because after that I assume it would have to be located.

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ProfessorX
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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Mon May 19, 2014 4:00 pm

Calm Man wrote:Professor, I am worried about this "banned substance". Is it potentially harmful if leaking to you or others? Also, if the pressure test shows there is a leak, will it actually localize it or just confirm it? Because after that I assume it would have to be located.
R-22 is being phased out as a coolant: http://www.epa.gov/ozone/title6/phaseou ... seout.html
Up until a few years ago most air conditioners used R-22 coolant.
Now new ones use something else.

The pressure test is supposed to determine for certain if the leak is in one or more of three places: (1) in the line set going through my walls from my roof to my basement, or (2) in the HVAC unit in my basement or (3) in the condensing unit on the roof.

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Re: advice regarding hard to find HVAC freon leak

Post by hicabob » Mon May 19, 2014 4:06 pm

With a car AC unit I have seen a mechanic add a fluorescent dye to the freon then he started the AC up and found the leak with a UV light (in a dark room). Perhaps similar would work for a house AC?

2retire
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Re: advice regarding hard to find HVAC freon leak

Post by 2retire » Mon May 19, 2014 4:11 pm

First thing I'd do is find a new company. $350 for a refill and a visual inspection seems outrageous. I think I only payed in the neighborhood of $150 when mine needed refilling a few years ago (that included the trip/service fee). I supposed you could live in a really high cost of living area, but that still seems outrageous.

Are you sure they didn't use any tools. They should have at least had a freon detector and checked all the joints and the coils. They aren't going to find anything with a visual inspection unless your pipes have massive cracks in them. If the detector can't detect anything, then yes, you need to do a pressure test to see if the problem could be somewhere in the walls.

Also, the product is banned because it contributes to ozone depletion, not because it is harmful to humans.

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ProfessorX
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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Mon May 19, 2014 4:36 pm

Yeah HVAC techs where I live charge $80+ an hour. Their leak checking visual inspection with soapy water last year took several hours.

The guys I have been using said the R-22 coolant is very expensive because of the EPA restrictions on it nowadays. They have big maintenance contracts with office buildings, and they also do large installs with big businesses, as well as small jobs like mine. They may be expensive but they seem honest. Their inspection included using soapy water to look for bubbles but no expensive tech gear like a freon detector.

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Re: advice regarding hard to find HVAC freon leak

Post by dickenjb » Mon May 19, 2014 4:42 pm

Is the system not under warranty? If it is, putting in the dye may void the warranty.

I had a similar problem and it turned out that the leak was in the inside coil. The pressure test did not reveal a thing until they sent out another tech who turned on my furnace (in July). Once the interior coil heated up the crack got larger and the pressure fell like a rock.

Fortunately everything was covered by a 10 year parts and labor warranty otherwise it would have cost 4 figures to diagnose and repair.

My system was 9.5 years old but used 134A refrigerant (Freon is a tradename of DuPont, the gernic name is refrigerant). I am surprised your 5 year old system uses R22, that stuff is going to be really expensive in a few years since production was limited by the Montreal protocol.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Mon May 19, 2014 4:49 pm

dickenjb wrote:Is the system not under warranty? If it is, putting in the dye may void the warranty.

I had a similar problem and it turned out that the leak was in the inside coil. The pressure test did not reveal a thing until they sent out another tech who turned on my furnace (in July). Once the interior coil heated up the crack got larger and the pressure fell like a rock.

Fortunately everything was covered by a 10 year parts and labor warranty otherwise it would have cost 4 figures to diagnose and repair.

My system was 9.5 years old but used 134A refrigerant (Freon is a tradename of DuPont, the gernic name is refrigerant). I am surprised your 5 year old system uses R22, that stuff is going to be really expensive in a few years since production was limited by the Montreal protocol.
I have a ten year parts warranty, no labor unfortunately. I didn't buy the unit but the people who did did not pay the small upfront amount for the extended labor warranty. Stinks.

Iorek
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Re: advice regarding hard to find HVAC freon leak

Post by Iorek » Mon May 19, 2014 4:50 pm

I had an older system, so not really the same, but when I had a leak I ended up concluding it wasn't worth trying to find it-- was going to cost too much and might not do much good vs. simply replacing it.

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ProfessorX
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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Mon May 19, 2014 5:39 pm

Yeah the builders who bought my HVAC unit probably bought it because they got it on clearance because it uses R-22. LoL.

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Re: advice regarding hard to find HVAC freon leak

Post by Ged » Mon May 19, 2014 6:16 pm

Calm Man wrote:Professor, I am worried about this "banned substance". Is it potentially harmful if leaking to you or others? Also, if the pressure test shows there is a leak, will it actually localize it or just confirm it? Because after that I assume it would have to be located.
R-22 is pretty low toxicity. The biggest hazard is asphyxiation in an enclosed space.

http://www.refrigerants.com/msds/r22.pdf

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Re: advice regarding hard to find HVAC freon leak

Post by pshonore » Mon May 19, 2014 6:40 pm

2retire wrote:First thing I'd do is find a new company. $350 for a refill and a visual inspection seems outrageous. I think I only payed in the neighborhood of $150 when mine needed refilling a few years ago (that included the trip/service fee). I supposed you could live in a really high cost of living area, but that still seems outrageous.

Are you sure they didn't use any tools. They should have at least had a freon detector and checked all the joints and the coils. They aren't going to find anything with a visual inspection unless your pipes have massive cracks in them. If the detector can't detect anything, then yes, you need to do a pressure test to see if the problem could be somewhere in the walls.

Also, the product is banned because it contributes to ozone depletion, not because it is harmful to humans.
Have you checked the price of Freon lately? Its only being produced in very small quantities.

http://articles.courant.com/2013-05-24/ ... efrigerant

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Re: advice regarding hard to find HVAC freon leak

Post by Ged » Mon May 19, 2014 6:54 pm

ProfessorX wrote:Yeah HVAC techs where I live charge $80+ an hour. Their leak checking visual inspection with soapy water last year took several hours.
The use of soap bubbles seems pretty strange to me. There are all sorts of relatively inexpensive devices available for refrigerant detection that would be far faster.

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ProfessorX
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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Mon May 19, 2014 7:08 pm

Ged wrote:
ProfessorX wrote:Yeah HVAC techs where I live charge $80+ an hour. Their leak checking visual inspection with soapy water last year took several hours.
The use of soap bubbles seems pretty strange to me. There are all sorts of relatively inexpensive devices available for refrigerant detection that would be far faster.
Can you tell me about these devices?

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Re: advice regarding hard to find HVAC freon leak

Post by hectorochoa » Mon May 19, 2014 8:08 pm

Had a new Carrier unit put in about two years ago. It did not seem to be running quite right so I called the same company who installed it for an inspection. Service tech found the refrigerant was quite low. The service tech went into my attic where the air handler is located and used a small electronic device that he said "sniffed" for refrigerant leaks. Within a few minutes the sniffer started to beep and he found one of the coils in my air handler was cracked and had a slow leak. Replaced part under warranty, minus a $200 charge for installation of the new coil and to top-off the refrigerant. A couple phone calls to Carrier corporate and they reimbursed the $200.

You can find sniffers at auto part stores and hardware stores such as Harbor Freight. I found one on Harbor Freight's website by Pittsburgh Automotive, Item #92514 for $70, cheaper on ebay. This item looked similar to what my HVAC service tech used to find my leak.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Tue May 20, 2014 6:38 am

hectorochoa wrote:Had a new Carrier unit put in about two years ago. It did not seem to be running quite right so I called the same company who installed it for an inspection. Service tech found the refrigerant was quite low. The service tech went into my attic where the air handler is located and used a small electronic device that he said "sniffed" for refrigerant leaks. Within a few minutes the sniffer started to beep and he found one of the coils in my air handler was cracked and had a slow leak. Replaced part under warranty, minus a $200 charge for installation of the new coil and to top-off the refrigerant. A couple phone calls to Carrier corporate and they reimbursed the $200.

You can find sniffers at auto part stores and hardware stores such as Harbor Freight. I found one on Harbor Freight's website by Pittsburgh Automotive, Item #92514 for $70, cheaper on ebay. This item looked similar to what my HVAC service tech used to find my leak.
Thanks! I wonder if I should buy one of those myself... It's cheaper than one hour of labor for these guys.

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Re: advice regarding hard to find HVAC freon leak

Post by dickenjb » Tue May 20, 2014 7:06 am

FWIW my leak was so slow the refrigerant sniffer did not find it - and the tech said it was good down to ppm levels. This is not a DIY project IMHO.

When they evacuate and pressure test, they can isolate the inside coil, outside heat exchanger, and lines between the two. Thus narrowing the search down to 1 of 3 subsystems. Pray that it is the lines as they just need to be brazed. If it is the internal or external coil, you are looking at 4 figure bill on top of fee for evacuation, pressure test, and refrigerant recharge.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Tue May 20, 2014 9:13 am

dickenjb wrote:FWIW my leak was so slow the refrigerant sniffer did not find it - and the tech said it was good down to ppm levels. This is not a DIY project IMHO.

When they evacuate and pressure test, they can isolate the inside coil, outside heat exchanger, and lines between the two. Thus narrowing the search down to 1 of 3 subsystems. Pray that it is the lines as they just need to be brazed. If it is the internal or external coil, you are looking at 4 figure bill on top of fee for evacuation, pressure test, and refrigerant recharge.
In my situation the lines are inside the walls of my house in unknown locations, so if it were the lines I would not be able to braze them. Instead I would have to run a new ugly line outside of my house somehow. Or I would have to move the HVAC from the roof to the back patio and call an electrician to route high voltage power to the back patio. I doubt that whole process would involve a small bill. At least if it were the inside coil or the outside heat exchanger then I would not have to do surgery on my whole house.

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Re: advice regarding hard to find HVAC freon leak

Post by Spirit Rider » Tue May 20, 2014 9:41 am

It is very unlikely for a leak to occur in a line set. It is far more likely to occur in one of the coils or in the connection between the line set and one of the coils.

Unfortunately, many HVAC technicians are lacking competent knowledge, skills, and experience. Twenty years ago, I took A/C installation and EPA certification courses from a local distributor. I read a college A/C and Refrigeration text book and an EPA study guide. I knew far more than most of the other students with 2-3 years of apprenticeship. Sadly with many of them, another twenty years wasn't going to help.

I doubt it has changed very much. Even with a decent HVAC company, it is probably luck of the draw on technician quality.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Tue May 20, 2014 2:49 pm

Thanks to everyone for your feedback!

I am researching purchasing a whole new HVAC system now. (Not sure what I am going to do.)

Does anyone know what are good brands of manufacturers that make HVAC systems? Is Lennox good? Coleman? Other brands? What is a good way to research HVAC brands?

One guy quoted me $5500 to just replace the cooling unit,
or $8500 replace cooling and heating and put in a better fan for increased circulation to the third floor of my house.
Last edited by ProfessorX on Tue May 20, 2014 2:50 pm, edited 1 time in total.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Tue May 20, 2014 2:49 pm

accidental double post

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Re: advice regarding hard to find HVAC freon leak

Post by earlyout » Tue May 20, 2014 3:11 pm

If you are getting quotes on new systems make sure you tell them about the current leak. The quotes you get may or may not include the cost of replacing the lines between the compressor and the air handler. I think you would be disappointed if you installed a new system and then found out you still had a leak.

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Re: advice regarding hard to find HVAC freon leak

Post by fandango » Tue May 20, 2014 3:41 pm

A new unit will probably cost you $6000 to $7000 (includes labor and components). Shop around and get some estimates (they vary widely). Lennox and Trane are two brands that I have had good experience with.

Replacing the coil will probably cost you around $600 for the coil and around $600 to $1200 for the labor. A lot of coils are now made in Mexico, and I have heard of entire neighborhoods having to replace defective coils. Check to see if your coil is still under warranty. I think most have a 5 or 6 year warranty on the part. You will still have to pay for labor.

It is common to put dye in the system to determine the source of the leak. The soapy water trick may work if the leak is around a joint. Since a lubricant is often blended into the refrigerant, you can also check for oil spots to identify the leaking area.

I have a service contract with my HVAC company. I get two seasonal inspections a year, two five inch wide filters, and a discount of any repairs that might be required. Usually, the technician will "top off" my unit to make sure refrigerant is at the optimal level at no charge. This service contract costs me $183 per year. My local electric company gives me a $75 rebate for the air conditioner tune up. With the filters costing about $30 each, this service contract is only really costing me $54 per year. Unfortunately, air conditioning is a necessity where I live. So, I do all I can to keep the system working.

Good luck with your repairs.

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Re: advice regarding hard to find HVAC freon leak

Post by Valuethinker » Tue May 20, 2014 4:27 pm

Calm Man wrote:Professor, I am worried about this "banned substance". Is it potentially harmful if leaking to you or others? Also, if the pressure test shows there is a leak, will it actually localize it or just confirm it? Because after that I assume it would have to be located.
Except in very high concentrations (like in the old fire prevention systems) CFCs are too inert to be directly harmful to humans.

http://ozonewatch.gsfc.nasa.gov/facts/hole.html

the discovery of CFCs and their effect on the atmosphere (it had always been believed they were too inert to do damage) ranks as one of the great scientific discoveries of the 20th century. As a result of the Montreal Protocol and later treaties, the world's nations have agreed to phase out CFCs. That's why it is banned.

Crutzen, Molina and Rowland shared the 1995 Nobel Prize in Chemistry for this discovery. James Lovelock had earlier hypothesized it but rejected the notion that it could cause significant damage. He invented the device that we use to detect CFCs in the atmosphere.

http://almaz.com/nobel/chemistry/1995a.html

http://www.humantouchofchemistry.com/james-lovelock.htm

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Re: advice regarding hard to find HVAC freon leak

Post by Saving$ » Tue May 20, 2014 7:16 pm

You have a 5 year old system still under warranty for parts but not labor. I would NOT replace it.
Invest $70 in your own leak detector. If you cant find the leak with it, sell it on ebay. Transaction costs = $20.

Call another HVAC service company and explain your situation, ask them what they charge for trip charge (sunk cost), per pound to recharge system, and leak detection. You might make 2-3 calls and decide on a different company. Make sure whomever you select can do the warranty claim on your equipment. Watch them closely. If the equipment is replaced under warranty they don't make a mark up on that, and they may spend more time than needed.

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Re: advice regarding hard to find HVAC freon leak

Post by baw703916 » Tue May 20, 2014 7:30 pm

Valuethinker wrote:
Calm Man wrote:Professor, I am worried about this "banned substance". Is it potentially harmful if leaking to you or others? Also, if the pressure test shows there is a leak, will it actually localize it or just confirm it? Because after that I assume it would have to be located.
Except in very high concentrations (like in the old fire prevention systems) CFCs are too inert to be directly harmful to humans.

http://ozonewatch.gsfc.nasa.gov/facts/hole.html

the discovery of CFCs and their effect on the atmosphere (it had always been believed they were too inert to do damage) ranks as one of the great scientific discoveries of the 20th century. As a result of the Montreal Protocol and later treaties, the world's nations have agreed to phase out CFCs. That's why it is banned.

Crutzen, Molina and Rowland shared the 1995 Nobel Prize in Chemistry for this discovery. James Lovelock had earlier hypothesized it but rejected the notion that it could cause significant damage. He invented the device that we use to detect CFCs in the atmosphere.

http://almaz.com/nobel/chemistry/1995a.html

http://www.humantouchofchemistry.com/james-lovelock.htm
Good summary, VT.

R22 (CHF2Cl) is actually a first-generation replacement for CFCs. The hydrogen atom reduces its ozone depletion potential by about a factor of 10 relative to the compound it replaced, R12 (CF2Cl2) (R22 can get destroyed before making it to the stratosphere). The currently-used compounds such as R134a (CF3CH2F) don't contain chlorine and so aren't ozone depleters, although they are significant greenhouse gases. There are some compatibility issues between the non-chlorinated refrigerants and existing equipment as of 1990, which is why R22 was used as an intermediate step.
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Re: advice regarding hard to find HVAC freon leak

Post by MathWizard » Tue May 20, 2014 9:17 pm

A system old enough to use R-22 is probably very inefficient. You'll probably be able to
pay for the system with the savings on electricity. I'd skip the test and get a new system.

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Re: advice regarding hard to find HVAC freon leak

Post by Valuethinker » Wed May 21, 2014 7:31 am

MathWizard wrote:A system old enough to use R-22 is probably very inefficient. You'll probably be able to
pay for the system with the savings on electricity. I'd skip the test and get a new system.
Only 5 years old so it sounds like the contractor or the specifier cut corners?

The number to look at is SEER.

http://en.wikipedia.org/wiki/Seasonal_e ... ency_ratio
Today, it is rare to see systems rated below SEER 9 in the United States because aging, existing units are being replaced with new, higher efficiency units. The United States now requires that residential systems manufactured after 2005 have a minimum SEER rating of 13, although window units are exempt from this law so their SEERs are still around 10.

Substantial energy savings can be obtained from more efficient systems. For example by upgrading from SEER 9 to SEER 13, the power consumption is reduced by 30% (equal to 1 − 9/13). It is claimed that this can result in an energy savings valued at up to US$300 per year depending on the usage rate and the cost of electricity.
For most Americans it is probably worth a 'reach' to SEER 14 or 15 if they are replacing. It is seldom (unless you live in a very high cost electricity area) replacing before you have to-- payback period is just too long.

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Re: advice regarding hard to find HVAC freon leak

Post by NHRATA01 » Wed May 21, 2014 8:07 am

MathWizard wrote:A system old enough to use R-22 is probably very inefficient. You'll probably be able to
pay for the system with the savings on electricity. I'd skip the test and get a new system.
Not necessarily true. R22 is actually a superior refrigerant from an efficiency standpoint vs R-123 or R-134A (much as the older R-12 was even better). I manage a utility plant with 2,000 ton industrial chillers. Our most efficient units date to the mid 80s utilizing R-22 and are better on a kW/ton basis over units 15-20 years newer with different refrigerants.

Now granted if the SEER rating on the compressor unit is much worse and the ancient coils are filthy, then yes overall the system is probably not as efficient as a newer would be. If you have an R-22 system I wouldn't rush to swap it out, however if you've got a leaking system refrigerant fills are going to start to get very expensive.

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Re: advice regarding hard to find HVAC freon leak

Post by baw703916 » Wed May 21, 2014 8:40 pm

NHRATA01 wrote:
Not necessarily true. R22 is actually a superior refrigerant from an efficiency standpoint vs R-123 or R-134A (much as the older R-12 was even better).
I'm just curious what the efficiency difference tends to be between R12, R22, and R134a. I'd hear the statement made that the original compound was the most efficient, but I don't have a very good sense of the numbers (my involvement in this area has been mostly involving fire suppressants--the bromine analogs of CFCs).
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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Sun May 25, 2014 12:09 pm

Thanks for everyone's help!

An HVAC tech came over with a leak detector and found out that my coils leak. Someone else recommended to me this product "easy seal". It is some kind of additive:

http://www.amazon.com/Nu-Calgon-EasySea ... B005DTLM1O

Some people say its a really bad idea, other people say it works. Anyone have any experiences with it? Thanks!

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Re: advice regarding hard to find HVAC freon leak

Post by Abe » Sun May 25, 2014 12:26 pm

I just went through this. My unit uses R-22 freon. It had a leak and all the freon leaked out. Because R-22 is being phased out, it is very expensive. The service man found a leak, fixed it and recharged the unit. The cost of the R-22 freon was $60.00 per pound and he put in 8 pounds. My total bill was a little over $600.00, and I still don't know for sure if there is another leak or not. The service man said that was the only one he found. I noticed one poster said they recharged a few years ago with R-22 and it didn't cost that much. It probably didn't cost that much back then, but it has gone up tremendously. AS for finding leaks, service people use a detector that will signal if there is a leak. The old way is still a good way and inexpensive. You can put dishwashinng liquid and water in a spray bottle and spray around connections and along the gas line. If there is a leak, it will bubble up. A lot of times, you only need to tighten a fitting to stop the leak. Hope this helps.
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Re: advice regarding hard to find HVAC freon leak

Post by fandango » Mon Jun 02, 2014 4:03 pm

Easy Seal is just a temporary fix at best.

You should just go ahead and replace the coil. Check to see if you have a warranty on the coil (manufacturer will tell you - sometimes there are "secret" warranties).

If so, you may just have to pay for labor.

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ProfessorX
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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Mon Jun 02, 2014 10:59 pm

fandango wrote:Easy Seal is just a temporary fix at best.

You should just go ahead and replace the coil. Check to see if you have a warranty on the coil (manufacturer will tell you - sometimes there are "secret" warranties).

If so, you may just have to pay for labor.
Thanks! What is a "secret" warranty?

So far I found the leak, or "a leak", and it is in the coils. To replace the coils with very good better coils and fix up my unit would cost $1850. To replace the coils and the condenser with a unit that uses r410a refrigerant would cost $4300. I am leaning towards just replacing the whole thing... but still not 100% sure... wouldn't want to spend $1850 to have the condenser fail within a few years and have to replace the whole thing anyway... supposedly running the condenser low on freon can cause it to fail early...

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Re: advice regarding hard to find HVAC freon leak

Post by interplanetjanet » Tue Jun 03, 2014 6:42 am

Abe wrote:The cost of the R-22 freon was $60.00 per pound and he put in 8 pounds.
That is a steep markup. Virgin R-22 is going for under $10/lb in 30lb tanks. It's worth mentioning that there are a number of R-22 alternatives that are EPA SNAP approved and while they generally require a full pumpdown, some do not require oil replacement (this makes the cutover much easier). They are not as widely used yet as R-22 is still quite affordable. There is an enormous installed base of R-22 systems and they should be maintainable for some time to come - though as has been mentioned, older systems should be scrutinized for expected lifespan and efficiency.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Tue Jun 03, 2014 7:34 am

interplanetjanet wrote:
Abe wrote:The cost of the R-22 freon was $60.00 per pound and he put in 8 pounds.
That is a steep markup. Virgin R-22 is going for under $10/lb in 30lb tanks. It's worth mentioning that there are a number of R-22 alternatives that are EPA SNAP approved and while they generally require a full pumpdown, some do not require oil replacement (this makes the cutover much easier). They are not as widely used yet as R-22 is still quite affordable. There is an enormous installed base of R-22 systems and they should be maintainable for some time to come - though as has been mentioned, older systems should be scrutinized for expected lifespan and efficiency.
Thanks! Yes it is a steep markup. R-22 sells for under $300 in 30lb containers on Amazon + shipping. But you have to have an EPA cert to buy it. And if you use it incorrectly then it can blow up in your face.

All the same, tech's in my area will only fill up my R-22 for $50-$100 per lb or more...

Anyway, since you are knowledgable, do you know how to answer any of my questions in my previous post (two up from this one)? Thanks again!

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Re: advice regarding hard to find HVAC freon leak

Post by Valuethinker » Tue Jun 03, 2014 8:03 am

ProfessorX wrote:
fandango wrote:Easy Seal is just a temporary fix at best.

You should just go ahead and replace the coil. Check to see if you have a warranty on the coil (manufacturer will tell you - sometimes there are "secret" warranties).

If so, you may just have to pay for labor.
Thanks! What is a "secret" warranty?
Manufacturers, for legal or market reputation reasons, extend warranties but do not publicize them-- you have to ask.
So far I found the leak, or "a leak", and it is in the coils. To replace the coils with very good better coils and fix up my unit would cost $1850. To replace the coils and the condenser with a unit that uses r410a refrigerant would cost $4300. I am leaning towards just replacing the whole thing... but still not 100% sure... wouldn't want to spend $1850 to have the condenser fail within a few years and have to replace the whole thing anyway... supposedly running the condenser low on freon can cause it to fail early...
On the second point imagine running your car without enough oil? Or without enough water in the rad? Hence the impact on life.

On the former I don't know what to advise you but 'kick don't splatter' is my general watchword/ bias - assuming I can afford it replace the whole thing with something newer (with a warranty). You can work out a present value calculation, whether it's worth it to you. But for me it's peace of mind. That is probably *not* the economically efficient answer.

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Re: advice regarding hard to find HVAC freon leak

Post by Abe » Tue Jun 03, 2014 9:46 am

ProfessorX wrote:

So far I found the leak, or "a leak", and it is in the coils. To replace the coils with very good better coils and fix up my unit would cost $1850. To replace the coils and the condenser with a unit that uses r410a refrigerant would cost $4300. I am leaning towards just replacing the whole thing... but still not 100% sure... wouldn't want to spend $1850 to have the condenser fail within a few years and have to replace the whole thing anyway... supposedly running the condenser low on freon can cause it to fail early...
I had a leak in my coil and had to add freon every year because the serviceman said they could not fix the leak. My furnace went out, so I decided to replace everything: furnance, coil and condensing unit outside. I could have replaced the coil and kept the old condensing unit but it used R22 freon and it would cost me a fortune over time to keep replacing it. It cost about $3,800. to replace the coil and condensing unit about 2 years ago. I posted earlier that I had to replace 8 pounds of R22 freon at another location and it cost over $600.00. If it were me, I would replace everything with the new R410a refrigerant.
Slow and steady wins the race.

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Re: advice regarding hard to find HVAC freon leak

Post by interplanetjanet » Tue Jun 03, 2014 2:47 pm

ProfessorX wrote:
interplanetjanet wrote:
Abe wrote:The cost of the R-22 freon was $60.00 per pound and he put in 8 pounds.
That is a steep markup. Virgin R-22 is going for under $10/lb in 30lb tanks. It's worth mentioning that there are a number of R-22 alternatives that are EPA SNAP approved and while they generally require a full pumpdown, some do not require oil replacement (this makes the cutover much easier). They are not as widely used yet as R-22 is still quite affordable. There is an enormous installed base of R-22 systems and they should be maintainable for some time to come - though as has been mentioned, older systems should be scrutinized for expected lifespan and efficiency.
Thanks! Yes it is a steep markup. R-22 sells for under $300 in 30lb containers on Amazon + shipping. But you have to have an EPA cert to buy it. And if you use it incorrectly then it can blow up in your face.
Thankfully the EPA section 608 and 609 certifications are really not that hard to get, though I may be biased (a background in physics and chemistry probably helped a little).
All the same, tech's in my area will only fill up my R-22 for $50-$100 per lb or more...

Anyway, since you are knowledgable, do you know how to answer any of my questions in my previous post (two up from this one)? Thanks again!
When you say "condenser", do you mean "compressor"? Running low on refrigerant can potentially cause early failure (the refrigerant solvates the oil in the system and keeps things lubricated) but there are underpressure sensors that should shut the compressor down if too much escapes the system.

I honestly don't know which way I'd go. I haven't been in the business for a while but that cost for coil replacement seems high. If the system is really only five years old, I'd probably get the coils done and take it from there. As another poster said, sealant additives aren't a good idea.

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Re: advice regarding hard to find HVAC freon leak

Post by Abe » Tue Jun 03, 2014 3:56 pm

interplanetjanet wrote: When you say "condenser", do you mean "compressor"? Running low on refrigerant can potentially cause early failure (the refrigerant solvates the oil in the system and keeps things lubricated) but there are underpressure sensors that should shut the compressor down if too much escapes the system.
I am not sure if you are asking me or the OP the above question. In my post, I was referring to the complete outside unit for a central A/C unit as follows:
A condenser unit used in central air conditioning systems typically has a heat exchanger section to cool down and condense incoming refrigerant vapor into liquid, a compressor to raise the pressure of the refrigerant and move it along, and a fan for blowing outside air through the heat exchanger section to cool the refrigerant inside
Slow and steady wins the race.

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Re: advice regarding hard to find HVAC freon leak

Post by Ged » Tue Jun 03, 2014 5:06 pm

baw703916 wrote:
NHRATA01 wrote:
Not necessarily true. R22 is actually a superior refrigerant from an efficiency standpoint vs R-123 or R-134A (much as the older R-12 was even better).
I'm just curious what the efficiency difference tends to be between R12, R22, and R134a. I'd hear the statement made that the original compound was the most efficient, but I don't have a very good sense of the numbers (my involvement in this area has been mostly involving fire suppressants--the bromine analogs of CFCs).
The efficiency of a refrigeration system depends on a lot more than just the refrigerant. I suppose one could say that you could build a system that would achieve 15 SEER for less money with R12 than R134a, but the reasons for that would be fairly complex and have more to do with things like the correct operating pressure, lubrication requirements and so on than a concept like 'refrigerant efficiency'. I think you would have to say there are a lot more high efficiency R-134a units in the field than R-12 units simply because that's what the market wants now vs what it wanted when R-12 was the primary choice of equipment suppliers.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Tue Jun 03, 2014 11:20 pm

Thanks to everyone for all your help!

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Re: advice regarding hard to find HVAC freon leak

Post by fandango » Wed Jun 04, 2014 7:44 am

A "secret warranty" is one not included in your documentation but given by a manufacturer when you ask because they have had numerous problems with the equipment.

They don't want to publish it, but it mysteriously it is given if you push them a little.

Very common in the car industry. Also occurs in the HVAC business if the manufacturer wants to maintain their reputation and can get the part supplier to foot the bill.

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Re: advice regarding hard to find HVAC freon leak

Post by ProfessorX » Wed Jun 04, 2014 7:52 am

fandango wrote:A "secret warranty" is one not included in your documentation but given by a manufacturer when you ask because they have had numerous problems with the equipment.

They don't want to publish it, but it mysteriously it is given if you push them a little.

Very common in the car industry. Also occurs in the HVAC business if the manufacturer wants to maintain their reputation and can get the part supplier to foot the bill.
Yeah thanks.

Well I have a York HVAC. I called the number on York's website, which directed me to another number. I called the other number, and it picked up with the same automated system as the first number, which again directed me to the second number that I just called. I pressed a few different buttons in the automated system after calling back again, and was directed to somebodies voicemail, and I left a message. I also filled out their web form asking for warranty information. I have read on some HVAC tech forums that around 6 years ago (exactly when my unit was installed) a lot of HVAC companies were having big problems with leaky Evap Coils. Even so, I am not expecting much...

I am also now thinking of planning to just replace it. So I went ahead and asked the other HVAC company to begin that process.

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Re: advice regarding hard to find HVAC freon leak

Post by Valuethinker » Wed Jun 04, 2014 7:59 am

Ged wrote:
baw703916 wrote:
NHRATA01 wrote:
Not necessarily true. R22 is actually a superior refrigerant from an efficiency standpoint vs R-123 or R-134A (much as the older R-12 was even better).
I'm just curious what the efficiency difference tends to be between R12, R22, and R134a. I'd hear the statement made that the original compound was the most efficient, but I don't have a very good sense of the numbers (my involvement in this area has been mostly involving fire suppressants--the bromine analogs of CFCs).
The efficiency of a refrigeration system depends on a lot more than just the refrigerant. I suppose one could say that you could build a system that would achieve 15 SEER for less money with R12 than R134a, but the reasons for that would be fairly complex and have more to do with things like the correct operating pressure, lubrication requirements and so on than a concept like 'refrigerant efficiency'. I think you would have to say there are a lot more high efficiency R-134a units in the field than R-12 units simply because that's what the market wants now vs what it wanted when R-12 was the primary choice of equipment suppliers.
Or perhaps put it another way the systems are optimized around a certain refrigerant?

It's the older equipment, which is running on replacements for the old CFCs that might run more efficiently on the original CFCs (which have been phased out).

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Re: advice regarding hard to find HVAC freon leak

Post by NHRATA01 » Tue Jun 10, 2014 8:27 am

Valuethinker wrote:
Ged wrote:
baw703916 wrote:
NHRATA01 wrote:
Not necessarily true. R22 is actually a superior refrigerant from an efficiency standpoint vs R-123 or R-134A (much as the older R-12 was even better).
I'm just curious what the efficiency difference tends to be between R12, R22, and R134a. I'd hear the statement made that the original compound was the most efficient, but I don't have a very good sense of the numbers (my involvement in this area has been mostly involving fire suppressants--the bromine analogs of CFCs).
The efficiency of a refrigeration system depends on a lot more than just the refrigerant. I suppose one could say that you could build a system that would achieve 15 SEER for less money with R12 than R134a, but the reasons for that would be fairly complex and have more to do with things like the correct operating pressure, lubrication requirements and so on than a concept like 'refrigerant efficiency'. I think you would have to say there are a lot more high efficiency R-134a units in the field than R-12 units simply because that's what the market wants now vs what it wanted when R-12 was the primary choice of equipment suppliers.
Or perhaps put it another way the systems are optimized around a certain refrigerant?

It's the older equipment, which is running on replacements for the old CFCs that might run more efficiently on the original CFCs (which have been phased out).
Apples for apples, if you had an R12 system with modern design considerations, it would be more efficient than an R134A system.

On a 2,000 ton chiller operating at load and virtually identically condenser water temperature, we pretty consistently see a 0.05kW/ton improvement on R-22 vs R-134a and almost 0.1kW/ton on R22 vs. R-123. I haven't been around long enough to see how the R-12 units operated but they dated from the late 60s so I would suspect they might lag based upon inferior design.

Here's a quick google search chart I found, but it compares the various refrigerants, the number you are interested in from an efficiency standpoint would be 4th from the bottom, horsepower per ton, bhp/ton which is basically how much power your compressor is consuming to provide a ton of cooling capacity. Lower is more efficient.

Image

Sorry for the digression but I figured all the enginerds out there would enjoy.
Last edited by NHRATA01 on Tue Jun 10, 2014 12:04 pm, edited 1 time in total.

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Re: advice regarding hard to find HVAC freon leak

Post by baw703916 » Tue Jun 10, 2014 11:50 am

NHRATA01 wrote:Image

Sorry for the digression but I figured all the enginerds out there would enjoy.
So about a 6% difference. That makes sense that it would be noticeable if comparing two systems both in good condition, but might be overshadowed in practice by the efficiency of the motor/coils. Thanks.
Most of my posts assume no behavioral errors.

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Re: advice regarding hard to find HVAC freon leak

Post by Valuethinker » Tue Jun 10, 2014 11:51 am

baw703916 wrote:
NHRATA01 wrote:Image

Sorry for the digression but I figured all the enginerds out there would enjoy.
So about a 6% difference. That makes sense that it would be noticeable if comparing two systems both in good condition, but might be overshadowed in practice by the efficiency of the motor/coils. Thanks.
Thank you both for a very interesting discussion.

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Re: advice regarding hard to find HVAC freon leak

Post by NHRATA01 » Tue Jun 10, 2014 12:03 pm

baw703916 wrote:
NHRATA01 wrote:Image

Sorry for the digression but I figured all the enginerds out there would enjoy.
So about a 6% difference. That makes sense that it would be noticeable if comparing two systems both in good condition, but might be overshadowed in practice by the efficiency of the motor/coils. Thanks.
Correct, can't disagree with that. On an industrial scale with a 2,000 ton chiller running at 4160V it would certainly be a bit more noticeable than an average residential ~2 ton running on 220V :)

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Re: advice regarding hard to find HVAC freon leak

Post by bnes » Tue Jun 10, 2014 10:33 pm

While one can't argue with the level of bogglehead enthusiasm,
perhaps asking the question at a site such as http://diy.stackexchange.com/ or http://hvac-talk.com/vbb/
might result in a more focused answer.

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