A/C question

[TardedPanda]

I have a 1982 Datsun 720 with A/C (in the deep south its necessity).  The a/c I THINK is a port option, its not factory from Japan, but added once it hit the dealership.  The HI and LOW side fittings are on the back of the compressor which is mounted on the driver side right next to the tensioner pulley.  Truck has been in my family since brand new, so no hack jobs and my uncle said it was on the truck when he purchased it brand new in 1982.

 

The A/C does not blow cold or cool, it blows warm air.  I know the Compressor clutch works bc it engages when I turn the fan switch lever, I havent tried to jump it but at least the clutch isnt seized.  In the manual, it says to pull that lever (fan speed lever) out to activate the A/C and that a light should come on.   My light doesnt come on and when I pull the lever, it doesnt pull and you cant push it in either. 

 

This old system has me a little baffled.  I know its R12 and I have a retrofit kit ready to install (not installed yet) but I want to make sure Im not missing something with AC.  No reason to waste money on freon and a retrofit if I have another issue I need to fix first.

 

I got a new bulb from work and going to try it when I get home.  Ill post up the result on that later.

 

If these old systems are low or out of freon would the light not illuminate?  All the controls are cable operated which Ive cleaned and verified all move correctly, except you cant 'pull' it out like the manual says.

 

Ive only been driving the truck for the past year, it sat for YEARS (maybe 8-10) with minimal use, quick grocery runs or just started and moved a few feet.  I dont know how long the AC hasnt worked, it hasnt worked since Ive had it though.

 

 

[ronnny]

on an 84 i had it was low on freon and the light still came on when i turned it on but blew air that was not cooled.  I know it was just low on freon because if i added a can it would be a little better for a few months.  I do not use it much anyway.  In ga here, ifin i was in fl might use it more.

[oldskoolvws]

Well...where to start. I feel you with the south though. I lived there for over 2 years and had to add A/C to my 4Runner.

 

The A/C does not blow cold or cool, it blows warm air.  I know the Compressor clutch works bc it engages when I turn the fan switch lever, I havent tried to jump it but at least the clutch isnt seized.  In the manual, it says to pull that lever (fan speed lever) out to activate the A/C and that a light should come on.   My light doesnt come on and when I pull the lever, it doesnt pull and you cant push it in either.

 

It would make sense IF the light was tied to the safety switch and you have no refirgerant in the system. I don't ever recall though any systems where the light was tied to the switch. That would mean the light would turn off / on each time the compressor cycled on pressure (which is condusive to ambient). A wiring diagrahm should be able to resolve this quickly. If this is by design, you may be out of refrigerant and the safety switch is open, causing you a no run situation. Checking the bulb might resolve your issue too.

 

This old system has me a little baffled.  I know its R12 and I have a retrofit kit ready to install (not installed yet) but I want to make sure Im not missing something with AC.  No reason to waste money on freon and a retrofit if I have another issue I need to fix first.

 

if your switching refrigerants, especially R12 to R134A, you'll need to change filter drier and remove as much oil from the system. This usually occurs on a good evacuation. I usually swap compressors too. You'll lose about 25% - 30 % effeciency with this swap. I just changed my filter dryer yesterday on my Toyota and I'm hitting 38* with R134A. If you can find R12 and can afford it, I would stick with R12, less headaches. I have 30lb bottle.

 

If these old systems are low or out of freon would the light not illuminate?  All the controls are cable operated which Ive cleaned and verified all move correctly, except you cant 'pull' it out like the manual says.

 

See my first response. Not really understanding that pull cable thing.

[TardedPanda]

 

If these old systems are low or out of freon would the light not illuminate?  All the controls are cable operated which Ive cleaned and verified all move correctly, except you cant 'pull' it out like the manual says.

 

See my first response. Not really understanding that pull cable thing.

 

 

 In the owners manual it says to 'pull' the fan lever switch to activate the AC.  Shrug.  It even says that if you dont activate the AC, the system will act like a traditional heater.  Ill take a pic of the owners manual when I get home.

[oldskoolvws]

The pull switch would activate (close) the compressor circuit....aka...send power to the clutch. That power usually turns the light on (to indicate A/C on) and also flows to a pressure switch which, if the pressure is correct, will keep the circuit closed. If the pressure is too high or too low, the circuit opens so that damage is not done to the compressor. Once power flows out of the switch, it goes to the compressor clutch. Obviously there's relays and fuses in there too.

 

The light has no indication of pressure condition. I'm envisioning the pull on the switch to only be about 1/2".

 

First step is to check that clutch engages when power is applied FROM the dash switch. If it does move on.

Next, check either hi/lo side for pressure. Just like a bicycle tire, listen for pressure.

 

My guess, if the system is complete, is that the refrigerant is gone via small leak in the lines or the compressor shaft.

[TardedPanda]

So i looked at the AC panel that has the controls labeled and where the AC light would illuminate...........its just a black fill hole, no bulb or any way to get a light to it.  I wasted about an hour last night re-inspecting everything until looking at the back of the AC plastic panel. 

 

 

 

 

This is the face, front and back.  You can clearly see that Im just an idiot.  the clutch kicks on when the you turn the ac lever fan speed, doing the retrofit today.  Maybe  I get lucky.

[millican]

You're not crazy. Some of the faceplates are labeled differently and have the A/C light.

[Dguy210]

Some of the old Mercedes guys will run propane in the R12 systems instead of retrofit.

 

http://www.peachparts.com/shopforum/tech-help/254928-ac-propane-stying-alive.html

 

Of course this is not legit for cars and I would never suggest anyone does this, even if it is used industrially for this purpose and as an auto refrigerant in other countries.

[Tinman]

Some of the old Mercedes guys will run propane in the R12 systems instead of retrofit.

 

http://www.peachparts.com/shopforum/tech-help/254928-ac-propane-stying-alive.html

 

Of course this is not legit for cars and I would never suggest anyone does this, even if it is used industrially for this purpose and as an auto refrigerant in other countries.

Amazing how well that works, too!  In theory.... of course....  I would never tell someone to do that....

[millican]

Even plain old air can be used as a "refrigerant"; it's just not very efficient.

[Dguy210]

Even plain old air can be used as a "refrigerant"; it's just not very efficient.

Except that propane is more efficient than R134a.

[millican]

That's pretty cool. Is it less popular with the manufacturers because it's flammable?

[Dguy210]

That's pretty cool. Is it less popular with the manufacturers because it's flammable?

Not really it is mostly the EPA rules. I'm not sure if the real justification is actually known although they do claim it is the "safety" issue. My best guess is there is not enough money in cramming through the EPA the certification necessary to get propane declared legal. It definitely is not that old patent myth (R12 went off patent in the 50's). Outside the US and some applications industrially they are used (usually a propane-butane mix).

 

Safety-wise all refrigerants are flammable, R12 and R134a have some very nasty by-products when burnt (think chemical weapons). They are "less" flammable then propane, but the volumes used for propane are way less as the fill for pressure on propane is much less than R12, we are talking ounces here. Also it's not like you aren't already moving highly flammable fluids around. 

 

The sad thing is hydrocarbon refrigerants are ozone neutral, cheap, effective, and are even more tolerant of contaminants like water in the system.

 

Excerpt text below from here: http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html

• What is EC-12a and what is its legal status?

  Because it has not been submitted for review under the SNAP program, EPA is not aware of EC-12a's chemical composition. EC-12a is not legal to sell or use in any refrigeration or A/C end-use as a substitute for CFC-12 or any other ozone-depleting refrigerant, because it has not been submitted for SNAP review.

• May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon® ," in cars?

  No. It is illegal to use hydrocarbon refrigerants like HC-12a® and DURACOOL 12a® as substitutes for CFC-12 in automobile or truck air conditioning under any circumstances.

• How did EPA make this determination?

  The Clean Air Act, as amended in 1990, required EPA to establish a program to review substitutes for ozone-depleting substances, including refrigerants. EPA's Significant New Alternatives Policy (SNAP) program carries out this mandate. Manufacturers of substitutes must submit information to EPA about the products, including ozone depletion potential, global warming potential, and toxicity and flammability data. EPA then compares these characteristics to both the refrigerant being replaced and the other available substitutes.

  Most refrigerants submitted to EPA for review under SNAP have been found acceptable, often subject to certain conditions. A full list of alternatives is available online. In particular, several refrigerants have been listed acceptable for use as CFC-12 substitutes in motor vehicle air conditioning, subject to certain conditions on their use. Each acceptable alternative refrigerant has been demonstrated to a) be safer for human health and the environment than the original refrigerant, and B ) pose a level of risk similar to that of other acceptable alternatives.

  Flammable refrigerants pose a special challenge, because air conditioning and refrigeration systems in the US have been designed to use nonflammable refrigerants. [EDIT: This is bullshit BTW!] They are not designed to protect users, service technicians, and disposal personnel from the possibility of fire. Therefore, the use of flammable refrigerants in existing systems may pose a risk not found with nonflammable fluids.

  Although new systems may be designed to provide that protection, they are not specifically designed so today. Demonstrating that a flammable refrigerant can be used safely in current systems, whether existing or new, requires a comprehensive, detailed, scientifically valid risk assessment.  EPA has required a risk assessment for flammable refrigerants since the inception of the SNAP program in 1994. An assessment must address potential leak scenarios such as collisions, servicing errors, and disposal procedures. In addition, it must consider ignition sources ranging from cigarette lighters or matches to sparks caused during a collision.

  OZ Technology has submitted reports that it states demonstrate the safety of using OZ-12® and HC-12a® in systems not designed to use such flammable refrigerants. However, after careful review of each document, EPA determined that none of the reports represented valid a risk assessment. Until such assessments are performed, EPA believes that flammable refrigerants like HC-12a®, OZ-12® and DURACOOL 12a® may pose potential risks not present when using nonflammable refrigerants. For these reasons, EPA does not allow the use of HC-12a®, OZ-12® or DURACOOL 12a® as substitutes for CFC-12 outside of industrial process refrigeration. (Note that HC-12a®, as reformulated to meet DOT requirements, is not permitted to be sold or used as a substitute for ozone-depleting chemicals in industrial process refrigeration, since it has not been submitted to SNAP for review.)

• Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?

  EPA has not yet received data that adequately address the safety issues of hydrocarbon refrigerants in applications other than industrial process refrigeration. Flammability risks depend on the type of refrigeration or air-conditioning system. Industrial process refrigeration, for instance, does not include air conditioning, which pipes refrigerated air directly into occupied areas. Industrial process refrigeration generally refers to complex customized appliances used in the chemical, pharmaceutical, petrochemical and manufacturing industries. Direct risk to human health is reduced in industrial process refrigeration; for example, access to areas near the system is typically restricted. In addition, other regulations exist to protect the safety of industrial workers.

  EPA will review any additional material that is submitted under SNAP regarding the safety considerations of using hydrocarbon refrigerants in systems other than industrial process refrigeration.

• Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?

  Because EPA has been directed by Congress, under the SNAP program, to consider the safety aspects of alternative refrigerants for CFC-12 (as well as their environmental characteristics), it is necessary to address the safety aspects of using a flammable refrigerant in motor vehicle A/C systems originally designed for CFC-12, before that refrigerant can be approved.

  There are good reasons why gasoline and other fluids may be used safely while the use of hydrocarbon refrigerants in A/C systems may not be safe. Gasoline and other flammable substances are used in systems designed specifically for flammable fluids. A gas tank is deliberately placed in the middle of the rear part of a vehicle to protect it against collisions. Air conditioner condensers, in contrast, are placed at the very front of the car to maintain good air flow. Unfortunately, this location means that condensers may be punctured during a front-end collision. Another difference is that unlike gasoline lines, air conditioners include lines that provide cooling directly to occupied areas -- in this case, passenger compartments. Flammability risk is extremely dependent on the specific system being considered; the simple presence of other flammable fluids in a car does not address the safety of using hydrocarbon refrigerants in an automobile air conditioner.

Other comments:

 

http://www.linde-gas.com/internet.global.lindegas.global/en/images/Linde Hydrocarbon Refrigerants17_11492.pdf

 

https://www.acca.org/archives/industry-resources/government-affairs/hot-air/8856

[oldskoolvws]

Some of the old Mercedes guys will run propane in the R12 systems instead of retrofit.

 

http://www.peachparts.com/shopforum/tech-help/254928-ac-propane-stying-alive.html

 

Of course this is not legit for cars and I would never suggest anyone does this, even if it is used industrially for this purpose and as an auto refrigerant in other countries.

 

 

Not really it is mostly the EPA rules. I'm not sure if the real justification is actually known although they do claim it is the "safety" issue. My best guess is there is not enough money in cramming through the EPA the certification necessary to get propane declared legal. It definitely is not that old patent myth (R12 went off patent in the 50's). Outside the US and some applications industrially they are used (usually a propane-butane mix).

 

Safety-wise all refrigerants are flammable, R12 and R134a have some very nasty by-products when burnt (think chemical weapons). They are "less" flammable then propane, but the volumes used for propane are way less as the fill for pressure on propane is much less than R12, we are talking ounces here. Also it's not like you aren't already moving highly flammable fluids around. 

 

The sad thing is hydrocarbon refrigerants are ozone neutral, cheap, effective, and are even more tolerant of contaminants like water in the system.

 

Excerpt text below from here: http://www.epa.gov/ozone/snap/refrigerants/hc12alng.html

• What is EC-12a and what is its legal status?

  Because it has not been submitted for review under the SNAP program, EPA is not aware of EC-12a's chemical composition. EC-12a is not legal to sell or use in any refrigeration or A/C end-use as a substitute for CFC-12 or any other ozone-depleting refrigerant, because it has not been submitted for SNAP review.

• May hydrocarbon refrigerants be used to replace CFC-12, commonly referred to as "Freon® ," in cars?

  No. It is illegal to use hydrocarbon refrigerants like HC-12a® and DURACOOL 12a® as substitutes for CFC-12 in automobile or truck air conditioning under any circumstances.

• How did EPA make this determination?

  The Clean Air Act, as amended in 1990, required EPA to establish a program to review substitutes for ozone-depleting substances, including refrigerants. EPA's Significant New Alternatives Policy (SNAP) program carries out this mandate. Manufacturers of substitutes must submit information to EPA about the products, including ozone depletion potential, global warming potential, and toxicity and flammability data. EPA then compares these characteristics to both the refrigerant being replaced and the other available substitutes.

  Most refrigerants submitted to EPA for review under SNAP have been found acceptable, often subject to certain conditions. A full list of alternatives is available online. In particular, several refrigerants have been listed acceptable for use as CFC-12 substitutes in motor vehicle air conditioning, subject to certain conditions on their use. Each acceptable alternative refrigerant has been demonstrated to a) be safer for human health and the environment than the original refrigerant, and B ) pose a level of risk similar to that of other acceptable alternatives.

  Flammable refrigerants pose a special challenge, because air conditioning and refrigeration systems in the US have been designed to use nonflammable refrigerants. [EDIT: This is bullshit BTW!] They are not designed to protect users, service technicians, and disposal personnel from the possibility of fire. Therefore, the use of flammable refrigerants in existing systems may pose a risk not found with nonflammable fluids.

  Although new systems may be designed to provide that protection, they are not specifically designed so today. Demonstrating that a flammable refrigerant can be used safely in current systems, whether existing or new, requires a comprehensive, detailed, scientifically valid risk assessment.  EPA has required a risk assessment for flammable refrigerants since the inception of the SNAP program in 1994. An assessment must address potential leak scenarios such as collisions, servicing errors, and disposal procedures. In addition, it must consider ignition sources ranging from cigarette lighters or matches to sparks caused during a collision.

  OZ Technology has submitted reports that it states demonstrate the safety of using OZ-12® and HC-12a® in systems not designed to use such flammable refrigerants. However, after careful review of each document, EPA determined that none of the reports represented valid a risk assessment. Until such assessments are performed, EPA believes that flammable refrigerants like HC-12a®, OZ-12® and DURACOOL 12a® may pose potential risks not present when using nonflammable refrigerants. For these reasons, EPA does not allow the use of HC-12a®, OZ-12® or DURACOOL 12a® as substitutes for CFC-12 outside of industrial process refrigeration. (Note that HC-12a®, as reformulated to meet DOT requirements, is not permitted to be sold or used as a substitute for ozone-depleting chemicals in industrial process refrigeration, since it has not been submitted to SNAP for review.)

• Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere?

  EPA has not yet received data that adequately address the safety issues of hydrocarbon refrigerants in applications other than industrial process refrigeration. Flammability risks depend on the type of refrigeration or air-conditioning system. Industrial process refrigeration, for instance, does not include air conditioning, which pipes refrigerated air directly into occupied areas. Industrial process refrigeration generally refers to complex customized appliances used in the chemical, pharmaceutical, petrochemical and manufacturing industries. Direct risk to human health is reduced in industrial process refrigeration; for example, access to areas near the system is typically restricted. In addition, other regulations exist to protect the safety of industrial workers.

  EPA will review any additional material that is submitted under SNAP regarding the safety considerations of using hydrocarbon refrigerants in systems other than industrial process refrigeration.

• Gasoline and brake fluid are flammable, but they're allowed in cars. Why not hydrocarbon refrigerants?

  Because EPA has been directed by Congress, under the SNAP program, to consider the safety aspects of alternative refrigerants for CFC-12 (as well as their environmental characteristics), it is necessary to address the safety aspects of using a flammable refrigerant in motor vehicle A/C systems originally designed for CFC-12, before that refrigerant can be approved.

  There are good reasons why gasoline and other fluids may be used safely while the use of hydrocarbon refrigerants in A/C systems may not be safe. Gasoline and other flammable substances are used in systems designed specifically for flammable fluids. A gas tank is deliberately placed in the middle of the rear part of a vehicle to protect it against collisions. Air conditioner condensers, in contrast, are placed at the very front of the car to maintain good air flow. Unfortunately, this location means that condensers may be punctured during a front-end collision. Another difference is that unlike gasoline lines, air conditioners include lines that provide cooling directly to occupied areas -- in this case, passenger compartments. Flammability risk is extremely dependent on the specific system being considered; the simple presence of other flammable fluids in a car does not address the safety of using hydrocarbon refrigerants in an automobile air conditioner.

Other comments:

 

http://www.linde-gas.com/internet.global.lindegas.global/en/images/Linde Hydrocarbon Refrigerants17_11492.pdf

 

https://www.acca.org/archives/industry-resources/government-affairs/hot-air/8856

 

 

Propane has been is a long time refrigerant. I am a 608 / 609 tech and have used a ton of variations of refrigerant. I still have a 30lb of virgin R12. So here's the deal on propane in a nutshell as it's been explained to me:

 

- Not for MANUFACTURERS use for vehicles sold in the U.S. The EPA is the not the regulatory agency on this one, the DOT is. Because it is a derivative of propane, the DOT classifies it as a flammable and not safe for vehicle manufacturing (collisions result in increased chance of explosion). Europe has been using it in auto's for years. It does however spook the EPA and they will not certify it as well as a regulated refrigerant.

 

- It can replace not only R12, but R22 and 134A systems as well and, in the case of 134A, will result in about 25% efficiency gain.

 

- Most of the propane blends contain 134A or a variation of blends. It is not pure propane.

 

- Caution is required when using for explosion hazard, but also, if there is a leak, it is considered an azeotrope I believe, and it will separate. This means if you have a leak, you cannot just "top it off" like a single blend, the system must be evacuated and refilled because the effective mix will be off resulting in poor or no cooling.

 

- it is legal to purchase and use in the U.S., depending on application.

 

And, in case you think I'm full of BS, we fill our EU (European Union) Model S' with propane prior to shipping in our manufacturing plant here in California. An, yes, I run propane in some of my cars and it works great.

[DFW720]

Hi All,  I just bought an 82 Datsun 720 and my AC isn't working at all, my mechanic says the compressor is shot, so I'm looking for either a replacement, a place that rebuilds them or is there another way possible replacing it with another Nissan system under the hood only, the trusck is completely stock and has the 2.2 gas engine.  Any help appreciated!