John S is correct
Absolutely no chance
The bacteria lives in water. Your car's air conditioning does not mix air and water.
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Your car's air conditioning does not mix air and water.
What about the small amount of water in the heater matrix that doesn't drain out? Say for instance the drain tube is blocked?
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If you mean that your heater matrix is leaking then your radiator/cooling system is on the way out. If you mean the water under the car from an a/c system it is condensation and should be pure(ish) water and thus harmless.
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Since legionella was discovered (if that's the right word) many design changes have been made in Plumbing and heating design.
These concentrate mainly on stored water and relate to the type of material of tanks and calorifiers, overflow and spillover levels but mainly to the temperatures of the stored water.
This can be very difficult in the case of stored cold water in some roof areas and we solved this by having no storage but systems fed directly by the incoming main.
Much of this is irrelevant to the home user apart from one aspect and that is showers.
Maintenance in Establishments (and should be incorporated in the home)consists of regularly cleaning the shower head for the dangers John pointed out earlier of air/mist borne bacteria.
alvin
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The wet cooling towers are the problem, as stated by many others.
The heat removed by the cooling process is rejected at the condenser, where the refrigerant vapour is condensed into a liquid and it?s latent heat of condensation is released.
In wet AC systems the condensers are cooled by water. The water is cooled at the cooling tower and recirculated. The cooling tower ponds tend to collect all the particles in the air, limescale, leaves, insects, etc, and are often at lukewarm temperatures, providing ideal conditions for the growth of many organisms. The water is intentionally sprayed into the air to cause some of it to evaporate, creating an aerosol of water droplets containing any organisms that have been cultivated in the water.
The legionella bacteria is present in water everywhere and will multiply if given favourable conditions.
The risk of infection is much greater for the elderly or infirm, so the disease has affected many hospitals, in the past. The risk wasn?t recognized until a group of elderly ex-servicemen, attending an American Legion Convention were felled by a hotel cooling tower in Philadelphia in 1976. The disease had existed prior to that, but had been regarded as yet another strain of pneumonia.
The HSE?s Code of Practice on Legionnaires? disease, L8, states that a foreseeable risk exists in;
a) water systems incorporating a cooling tower;
b) water systems incorporating an evaporative condenser;
c) hot and cold water systems;
d) other systems containing water at which is likely to exceed 20 degC and which may release a spray or aerosol.
Car AC system use air-cooled condensers, so present no risk.
However, I?ve often wondered about screen washer bottles. They?re never cleaned, are kept nice and warm in the engine compartment, and contain an algae soup which is sprayed around in city centres by the washer jets and atomized by the water?s impact with the screen.
Does anyone have any thoughs on this? Will UV sterilization become a legal necessity?
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Someone recently recommended running your car on max air con cold for 15 mins and then on max hot for the same to get rid of the bacteria.
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Do a search - HJ has had a lot to say about how you should use your aircon systems to avoid difficulties, with or without the Foreign Legion.
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There seems to be a lot of confusion and needless panic here. There is no possibility whatsoever of Legionaires Disease developing in car air con systems. The only problem to which HJ refers is lack of lubrication causing the system to fail if it not regularly used.
The person with the fungus on his pollen filter will probably find it was all on the outside of the filter, which was doing its intended job. It should have been changed sooner to ensure adequate ventilation and keep windows from misting up.>> Do a search - HJ has had a lot to say
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No panic here. There's only a legionella risk if a system contains water at 20 to 50 degC and it releases an aerosol. There's more chance of finding Bruce Willis up your car's AC ducts than of finding legionella.
HJ's advice was to run the AC in winter to circulate the refrigerant & oil, and to run it on full heat for at least 15 minutes per week, in summer or winter, to kill any bugs that might make unpleasant smells. Legionella wasn't mentioned.
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How does a car's aircon work?
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I have just found a large, muscular, bald fellow jammed up against the filter inside the air-con duct, he claims my car been hi-jacked by international criminals who want to hold it for ransome - should I take any notice ??
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Pugugly,
If he is holding your car for RANSOME he only wants your lawn mower!
Bill
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Sorry - tired and emontional when written.....read it back knew it looked wrong, but the beer goggles wouldn't allow me to figure out which word !
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I have just found a large, muscular, bald fellow jammed up against the filter inside the air-con duct, he claims my car been hi-jacked by international criminals who want to hold it for ransome - should I take any notice ??
Yes. I recommend you change the filter.
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Thanks for that but could not find anything on car air conditioning
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I'll try my best at a layman's descripton of a fridge cycle...
There are basically 4 parts to an air con system - compressor, expansion valve, condenser and evaporator. What the air con does it to pump heat from the airflow entering the car to outside the car. Let's start at the evaporator. This is located in the heater unit in the car. Air from outside passes over the evaporator and gives away heat (thus it is cooled). The heat is absorbed by the refrigerant, which is liquid and inside the evaporator, causing it to boil I would expect the refigerant in a car system to be boiling at just above zero deg C to avoid ice formation on the evaporator - water is condensed out of the air as it is cooled, and if the refigerant was below zero V, ice would form. The refigerant vapour is now passed to the compressor (driven by the engine) where its pressure is increased. Because of the change in boiling point with pressure (eg water boils at 100deg C at atmospheric pressure, but 121 deg c at 1 bar - ie in a pressure cooker) the refigerant can now be condensed at atmospheric temperature - this happens in the condenser (usually situated in front of the radiator) - air leaving the condenser will feel hot if you hold your hand in it, where the heat removed from the air entering the car, plus the heat input by the compressor, is removed by condensing the refigerant. I would expect the condenser to run at around 60 - 70 deg C, to make sure it will work in almost all outside conditions. Liquid from the condenser is then reduced in pressure through the expansion valve, and because its pressure is reduced, its boiling point also falls, so some of the refrigerant boils, and its temperature drops (eg if you take the lid off your pressure cooker at 121 deg C it boils violently and makes lots of steam until the temp drops back to 100 degC). Condensed liquid then passes back to the evaporator to start the cycle again. This is exactly the same as how your domestic fridge freezer works - but not your caravn fridge - they use absorption fridges, and I can't really explain the thermodynamics behind those!
The really interesting thing about fridges is that they do more work than you have to put in! eg If you car air con can remove say 5kW of energy from the air entering the car, then the compressor only has to do about 1.5kW of work. Neat eh? Slightly off topic, this allows you to heat your house by 'pumping' heat in from the ground outside, and you only need to put in about 1/3 the energy that a conventional gas system would need. High set up costs unfortunately....
Richard
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budu said "Slightly off topic, this allows you to heat your house by 'pumping' heat in from the ground outside, and you only need to put in about 1/3 the energy that a conventional gas system would need. High set up costs unfortunately...."
I experienced one of these systems at a client's premises many years ago.
Most impressive as you get heating in the winter and air conditioning in the summer from the same system.
As to set-up costs, assuming an average domestic gas bill is just over £400, the savings come to about £150 per annum, so there is quite a long payback period to cover the outlay of several thousand, even assuming that no servicing or repairs is required in the meantime.
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However, I?ve often wondered about screen washer bottles. They?re never cleaned, are kept nice and warm in the engine compartment, and contain an algae soup which is sprayed around in city centres by the washer jets and atomized by the water?s impact with the screen. Does anyone have any thoughs on this? Will UV sterilization become a legal necessity?
I don't like to say I told you so (as my wife often says) but I did, about eight years before the HSE recognised that windscreen washer bottles were a hazard.
www.bbc.co.uk/news/10293519
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