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wass

Air Conditioning Or Air "con"?

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Having read that a typical cost of air conditioning service might be £90 assuming nothing was found to be at fault,, I smiled to myself. The last time I had our prius serviced , they recommended an air conditioning service and I asked what this would entail. I was informed that the refrigerant needed to be changed due to its age and the system needed to be cleaned.

My background encompasses several years spent in the air conditioning industry and the service description made me smile in that I could see no point in putting the "expert" on the other end of the phone right.

Air conditioning technicians have to be properly trained which normally takes a minimum of 3 years (rather than a 4 week module on a motor mechanics course) and additionally, they need to be regularly updated and appraised of the latest F gas regulations which are in place to police the refrigeration industry with one of the principal aims being to prevent the release of refrigerant gases to the atmosphere..

A refrigeration service should consist of checking the refrigerant charge level, tracing and repairing all leaks, where necessary, cleaning condensing coils where possible , cleaning and disinfecting evaporator coils, cleaning, disinfecting and unblocking condensate drainage systems, checking off coil temperatures and cleaning or changing air filters. At no point does changing refrigerant because it is old, worn out or just for the hell of it enter into the procedure.

Granted, in order to find a leak it is good practice to remove all refrigerant and send it away to be recycled, pressurise the system with dry nitrogen in order to locate and repair the leak ( it is also possible to recharge the system with a UV sensitive dye marker in order to allow future leaks to be more easily detected).

Most modern car air conditioners still use a type of refrigerant which first came onto the market about 20 years ago. This refrigerant is referred to as R134A. One of the well known snags with R134A is that it is a mixture of compounds and one of the components of the compound has an extremely small molecular size meaning that it can actually migrate through apparently solid copper pipes! The result of this means that the entire compound becomes ineffective as a refrigerant and the air conditioning ceases to be able to cool whilst the operating pressure of the refrigerant appears close to normal. It is this phenomenon which leads to people thinking incorrectly that there is a need to routinely change refrigerant.

The motor industry in general have turned a blind eye to this publicly but have never the less, developed air conditioner systems which have additives and coatings on the various components which will seal the tiny and almost impossible to detect sources of leaks. Modern air conditioner systems are therefore far more reliable than their ancestors of 10 years ago and more. Modern air conditioner systems which leak refrigerant will, most likely have a good old fashioned leak which requires fixing and a good place to start is at the pipe unions and flexible pipes.

An air conditioner service should take approximately 15 minutes plus the cost of a pollen filter and a few squirts of disinfectant and given that it would be carried out at the same time as general routine service should not cost anything like £90.

Air conditioner repairs however, are a minefield. The cost in labour may be extremely high due to the nature of the refrigerant. It may take hours to painstakingly trace a leak.. Given the nature of some of the leaks, it can even be necessary to start to guess at which components may be porous and replace them on a trial and error basis. Given thiese diffficulties, it becomes easier to see why garages may wish to harvest funds from the routine jobs in order to subsidise the costs of fault diagnosis.

Roll on the day when some clever person develops a refrigerant which has large sized molecular constituents which would allow for simpler leak detection techniques than currently used by professionals on R134A systems.

Needless to say, I service my air conditioning myself and would not hesitate to have the car professionally degassed and not bother repairing the leak should one materialise since the cost of a lasting repair would probably be totally disproportionate to the residual value of the vehicle with air conditioning not working.

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Very informative, thank you Wass :thumbsup:

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<snip> Given the nature of some of the leaks, it can even be necessary to start to guess at which components may be porous and replace them on a trial and error basis. Given thiese diffficulties, it becomes easier to see why garages may wish to harvest funds from the routine jobs in order to subsidise the costs of fault diagnosis. <snip>

I have no personal practical experience to fall back on but somehow I doubt that any garage would be using any excess margin on a £90 A/C service to subsidise a system that needed a significant amount of remedial work ;)

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The last time I had my A/C serviced was with the 60,000 Full service. It cost £59.90. Today, I have just received a flier inviting me to have my A/C professionally serviced for £49.99. :)

This thorough service, done by our qualified air conditioning experts, tests your system for leaks, cleanses and recharges your air conditioning system using an anti-bacterial additive ensuring cool and enjoyable motoring.

One other thing, a/c systems do benefit from being used regularly.

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I believe hybrids cost more for air con servicing as the lubrication Oil is different and shouldn't be crosscontaminated with normal lubricants...something to do with the resistivity of the system.

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Wass - I think it possible you may have been referring to my post where I quoted my aircon service @ £90. Indeed this was after I negotiated a 10% discount too!

A breakdown of the charges - Labour 1.10 @ £46.17 = £50.79; Element Air RE @ £14.71; Air Con Treatment @£9.50, the whole lot plus VAT = £90. I have quoted these charges exactly as they appeared on my invoice.

This work was 'recommended' to me as needed doing when I was waiting for the car to be serviced. As I travel 30 miles to use my favoured dealer I thought I might avoid one additional trip.by having it done with the car service. Probably I could have found an aircon specialist much closer to home, but prefer only Toyota hands fiddling with my car.

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One other thing, a/c systems do benefit from being used regularly.

This is true of older , engine driven compressor systems since regular use improves the chances of the compressor seals surviving. Newer, electrical air conditioning compressors being hermetically sealed do not suffer from lack of use.

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I believe hybrids cost more for air con servicing as the lubrication oil is different and shouldn't be crosscontaminated with normal lubricants...something to do with the resistivity of the system.

R134A refrigerant systems must run on synthetic Oil which must never be contaminated with mineral Oil and this has nothing at all to do with the air conditioning being fitted to a hybrid car.This is true of all cars which use R134A air conditoning systems even my old diesel Volvo. As a general point , the gas side of the air conditioning system is entirely self contained and has nothing at all to do with any other lubrication system on the car. Changing or even accessing the Oil in an air conditioning system is something which rarely happens since it is work which is associated with a compressor change.
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One other thing, a/c systems do benefit from being used regularly.

This is true of older , engine driven compressor systems since regular use improves the chances of the compressor seals surviving. Newer, electrical air conditioning compressors being hermetically sealed do not suffer from lack of use.

Thanks Wass, good to know. In any case I'll continue using my climate control on auto with the A/C on. I find the ride much more pleasant regardless of the weather outside, and my experiments with and without A/C made no material impact on MPG's.

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Thanks Wass for a very informative article on a/c systems. I kept up with most of it so maybe my previously aquired knowledge wasn't too far off the mark.

One query I have is regarding the horrible smell that seems to start to come out of the air vents around this time of year. I've always understood this to be mould growing on the evaporator giving off the smell and the reason it seems to happen in the autumn is that the system has been used all summer but is now having gaps in its use due to lower ambient temperatures so climate systems don't turn on the compressor. When I've had manual aircon I've avoided the smell by leaving the a/c on all year and blending in heat so I don't freeze. This also kept the air inside nice and dry. With climate control systems it seems that even when the a/c is switched on it is only actually on when the system decides so you can't avoid intermitant running (and thus a smelly evaporator!). You mention a good service including dissinfecting the evaporator. I'm guessing that is what the £9.50 aircon treatment is in duffryns bill. I've seen the Forte aerosols for this and once bought one off ebay - set it off inside the car with the fan on full and on recirculate, jump out quick and leave it to run through the air vents and hopefully some of it makes it to the smelly bits! This does work but the smell comes back in a few months. Is there a better way to do a DIY dissinefect?

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Thanks Wass for a very informative article on a/c systems. I kept up with most of it so maybe my previously aquired knowledge wasn't too far off the mark.

One query I have is regarding the horrible smell that seems to start to come out of the air vents around this time of year. I've always understood this to be mould growing on the evaporator giving off the smell and the reason it seems to happen in the autumn is that the system has been used all summer but is now having gaps in its use due to lower ambient temperatures so climate systems don't turn on the compressor. When I've had manual aircon I've avoided the smell by leaving the a/c on all year and blending in heat so I don't freeze. This also kept the air inside nice and dry. With climate control systems it seems that even when the a/c is switched on it is only actually on when the system decides so you can't avoid intermitant running (and thus a smelly evaporator!). You mention a good service including dissinfecting the evaporator. I'm guessing that is what the £9.50 aircon treatment is in duffryns bill. I've seen the Forte aerosols for this and once bought one off ebay - set it off inside the car with the fan on full and on recirculate, jump out quick and leave it to run through the air vents and hopefully some of it makes it to the smelly bits! This does work but the smell comes back in a few months. Is there a better way to do a DIY dissinefect?

Avoiding the dreaded smell from air conditioning systems is a bit of a balancing act. In many cases the smell is caused by bacteria. I was talking with a pathologist about this phenomenon and referring to antibacterial treatments of air conditioner coils being relatively ineffective compared to cleaning the evaporator coil and flushing out any contamination. He informed me that the smell from most air conditioning system did originate mostly from bacteria but rather more decomposing bacteria rather than the live ones. This explained the reason for disinfection being short lived.The best way to avoid the smell from the system is to attempt to remove any bacteria enhancing conditions. Try to keep the condensate drains as clear as possible so that any moisture can easily drain away. Additionally, keep the cabin filter changed regularly take out the mats regularly and beat the much and fluff out of them whilst vacuuming the remaining carpets to avoid the evaporators becoming dirty and avoid running the system on recirculation rather than fresh air since recirculating the same air will always be circulating the same bacteria and encourage colonisation. Something I have always tried to do with ac systems is to run them for quite long periods at extremes of temperatures which don't agree with the constitutions of your average bacterium: giving them an ultra cold blast in the winter and a blisteringly hot blast in the summer. This doesn't make driving very comfortable but it does seem to do the trick by wiping out the nasties with extremes of temperature rather than cosseting them. I just don't suffer from smelly ac systems but I can not say categorically exactly what it is I do which keeps that smell of horse pee away.
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Is it only Toyota/Lexus dealers who have the kit to recharge hybrid aircon as my local specialist wont touch them as they use ND11 Oil?

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Although, you can also perform maintenance tasks on your ac unit all by yourself. It is though always advisable to let a professional take care of tasks like maintenance requirements of your ac unit. Any experienced ac repair specialist can do a good service of your ac system.

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Something I have always tried to do with ac systems is to run them for quite long periods at extremes of temperatures which don't agree with the constitutions of your average bacterium: giving them an ultra cold blast in the winter and a blisteringly hot blast in the summer. This doesn't make driving very comfortable but it does seem to do the trick by wiping out the nasties with extremes of temperature rather than cosseting them.

I do exactly the same thing, and it works!! I also tend to run the AC pretty much all the time, as it acts as a dehumidifier.

I think one major point is if you run the AC at maximum heat until it becomes uncomfortable helps dry out the cabin, then blasting full cold helps to remove the now humid air, helping to dry things out, and helping prevent bacteria from growing in the first place. I also never run recirc mode except when passing fields where farmers are working, or for external smoke avoidance (as well as turning off the fan).

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Having my Prius air con checked out Friday morning, hope it just needs a recharge - there is some cooling there, but nothing like cold. Booked the appointment and the guy asked what car, as soon as I said Prius he said that needs a "special" Oil (different) due to it being electric (hybrid) car.  Basic cost is £60, done at my home, which includes leak detection. Don't know if "special" Oil is an extra or not.

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This is something I only found out about a couple of weeks ago, but there's actually a "sight glass" in the aircon system in the Prius (3rd gen anyway). If you see bubbles in the glass (running at lowest temp with max. fan speed) then it may suggest it needs regassing, but I think there's a bit of black magic to it (bubbles may be OK in certain situations).

https://priuschat.com/attachments/ac-air-conditioning-check-sight-glass-pdf.57256/

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7 hours ago, Catlover said:

Having my Prius air con checked out Friday morning, hope it just needs a recharge - there is some cooling there, but nothing like cold. Booked the appointment and the guy asked what car, as soon as I said Prius he said that needs a "special" oil (different) due to it being electric (hybrid) car.  Basic cost is £60, done at my home, which includes leak detection. Don't know if "special" oil is an extra or not.

My guess is that the "special Oil" they refer to is  because hybrid ac systems run with hermetically sealed electric motors inside the refrigerant system. whereas a lot of more conventional cars run with a crank driven compressor. The "special Oil " is probably the commonplace Oil used in everyday mains powered  deep freezers which also have hermetically sealed electrical compressors running within the refrigeration system. Special ( as in not commonplace)for cars, maybe but commonplace in a lot of commercial kitchens  nevertheless.

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Apparently it's normal R134A refrigerant but with a special non-conductive compressor Oil for hybrids added.

see: Priuschat

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The air con on my Yaris was starting to smell at 2 years old, so at the service I asked them to clean the air con and it seems to worked. So far, no smell.

I tend to run the climate control on the cold/cool side, so I give a blast of hot once a month to keep things ticking over (I used to do this on my old car but I hadn't done it on the Yaris aside from in the previous winter). Time will tell how effective this is. So far, so good. I don't know how they cleared it last time.

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