R32 Aircon Refrigerant Temp

[Cubes]

Hi ppls,

I've always had a small issue with my A/C where entering diagnostic mode then back out again would fix.

NOW however its being really stuborn.

Doing the temp sensor check all appear to be fine but one (Refrigerant temp) that sits at -30.

When at -30 the compressor will not engage. *Sometimes* the sensor plays good, reads in the +'s and the a/c works perfectly fine.

In diagnostic mods I can force the a/c to engage via one of the options and it engages, blows cold air etc but its not that cold as its more of a flap test with the a/c on where it mixes 25% a/c and 60% vent or something.

Does any one know where this refrigerant temp sensor is?

[predator]

Does any one know where this refrigerant temp sensor is?

yes.. enjoy..

Once you have taken apart the entire speedo, glovebox, dash pad out, get back to me in 2 hours time and I'll show you where it is..

ok..

now, you've got to that step - its in the second box after the blower on the LHS of that photo.. its clipped to the piping within the aircon condensor? (metal thing) inside the plastic box. If I remember correctly you have to take the fan out to get to it.. that was a prick too.

still feeling brave?

Edited January 19, 2007 by predator

[Cubes]

LMAO...

Oh no.

I've since discovered the Inlet Air Temp sensor is also shagged. :S

In the 33's thats sitting in the blower box in front of the filter? :S I think. :S

[Cubes]

Now for an even bigger.

OH NO!!!

I just got under and had a little look and what do I see....

Some slippery green coolant stuff. Heater core leaking oh no.

Looks like that dash is coming out. :S

[RANDY]

Well, as per the picture above, make sure there is the obligatory hammer there, so your dash knows you mean business!

[Cubes]

Predator,

Do you still have that web page of yours?

[Godzilla32]

LOL obligatory hammer! Funny man.

Your condensor is mounted on the front of your car in front of the radiator so i can safely say its not attached to that. Sounds more like your describing your evaporator and the TX valve.

I had a look in my manual and i cant pin point where the refrigerant temp sensor is. Would be located somewhere on one of the air con pipes/hoses i would think.

Check both the evaporator core for leaks and the heater core as if there is a dye added to the ac system is will look green and be slippery and will come from a leaking evaporator core.

Good luck

[Cubes]

The aircon has recently been redone (2 days ago) and does have a dye in it.

It was pressure tested, condensor to a/c compressor replaced and refilled with R12A.

[Godzilla32]

Once you can get to the boxes under the dash you can remove them individually. From the left is the blower then the evaporator then the heater core. Remove the evaporator first (in the middle) and separate the box so check it for leaks/oily stains. On reassembly make sure you get some new foam to seal up the joins of the boxes from clark rubber. If you dont have a leak in the evaporator take a look see at the heater core. Its harder to remove and harder to separate. There is a main flap in it (air mix door?) that runs thru the guts of it and took me awhile to realise on one end of it there is a small screw holding the middle of it together. So dont force it. There is a reason its not coming apart hehe

Deren

Edited January 19, 2007 by Godzilla32

[Godzilla32]

You think your interiors stripped and looking scarey? You should see my whole car!

[Cubes]

Cheerz Darren.

Let the fun begin. :S

[Cubes]

Checked it out this morning.

Its definitely coolant.

All though that is good (as I've just paid to get the a/c serviced) its also bad as its harder to get to.

[RB30-POWER]

wanna be careful with r12a in there a well, being hydrocarbon based its extremely flammable. wanna hope your evaporator never leaks whilst anyone is smoking in the vehicle.

sure the performance and head pressures are better, but safety is always a concern when using blended hydrocarbons instead of r134a.

[Cubes]

That was explained to me and I have done a 'little' research of my own before giving the nod.

A lot of the R12a hysteria is created by the exaggeration of chemical companies

R134a with the oil suspended mixed with air is flammable at a low 200 something degree's and when it does go up it is extremely toxic, r12a on the other hand requires high 800's and isn't toxic.

There simply is not enough gas in the system to create such a concentration within the cabin for a cigarette, naked flame or red hot metal to ignite the R12a should the evaporator spring a leak.

Punch a hole in the hose and light it and you will see a flame the size of a blow lighter.

A heater hose that springs a leak and having Glycol sprayed as a fine mist is much more flammable than R12a.

Under no circumstance will it 'blow' you up, there simply is not enough r12a within the system.

If it catches fire then R134a would have also in the same circumstance; according to statistics.

[Cubes]

Unsure exactly how credible this bloke is but none the less its an interesting read and it supports everything I have read. I haven't came across any evidence that states R12a has been the cause of a vehicle fire that would not have otherwise occured.

John Stephenson is the secretary of the Durham Electric Vehicle Association.

R12a Refrigerant

Re your question in the SVAO Newsletter, and our recent conversation.

R12a is what is called a 'natural refrigerant' because it is a mixture of stable organic compounds, which have been around forever (?). It is a mixture of stable hydrocarbons to which the name 'paraffin's' was given in the early days of the study of Organic Chemistry. The mixture consists of approx. 40% butane, 59% propane and 1% ethane. Note that these materials are said to be 'highly purified' in order to use them as a refrigerant. You should not try to mix these materials out of a standard cylinder and expect that the air conditioning system will work perfectly.

It is well known that ethane, propane and butane are flammable in air and, when mixed in certain proportions with air, will burn with explosive speed. Nevertheless, propane and butane were used as refrigerants, along with ammonia, carbon dioxide, and sulphur dioxide, before the development and commercial use of freons in the early 1930's. It was an explosion involving propane in a school air conditioning system, which resulted in the death of a number of students, which lead to the banning of the 'natural' (flammable) refrigerants, in favour of the 'freons' in North America. At that time, the damaging environmental properties of the freons were not even imagined. As a family of products they were considered to be unreactive, non-toxic, non-flammable, i.e. the perfect refrigerants.

In the late 1970's the environmental effects of the freons began to be known and understood. They are, as a group, very damaging to the stratospheric ozone layer, and very strong global warming agents. As a result of the damage done to the stratospheric ozone layer, the freons, known as the cfc's or chloro-fluoro-carbons, have been banned by international treaty (although still available if you know where to buy them!). The fact that they are very strong global warming agents is less well known, and to some extent the chemical manufacturers have tried to keep this a dark secret.

The chemical manufacturers have introduced new compounds of the freon type to replace the banned

cfc's. The new compounds are hydro-chloro-fluoro-carbons (hcfc's) and hydro-fluoro-carbons (hfc's).

The hcfc's are in the process of being banned because they still affect the ozone layer (at about 5% or less, than the cfc's) and because they are strong global warming agents. The hfc's have no adverse effects on the ozone layer, but are still very strong global warming agents. There is one other group that must be mentioned - the per-fluoro-carbons, which are extremely stable compounds (have long lifetimes in the atmoshpere) and are strong global warming agents.

The following table summarizes the ozone depleting and global warming characteristics of the common refrigerants, with the 'natural' hydrocarbon refrigerants included for comparison:

Note: Global warming potential is calculated by using carbon dioxide =1 (i.e you can compare the effect of releasing 1 tonne of the various agents). Also, the lifetime of the various agents in the atmosphere has to be taken into account. For this reason the global warming potential (GWP) is calculated for time horizons of 20 years, 100 years and 500 years. Thus the GWP for an agent which has a short lifetime in the atmosphere will be at its highest when averaged over the 20 year Horizon and an agent with a long lifetime will be highest when averaged over the 500 year Horizon. In general, we are most immediately concerned with the 20 year time horizon, because it affects the most immediate future of the planet.

Refrigerant Ozone depletion Global Warming Potential

20 yr 100 yr 500 yr

Carbon Dioxide No

R12 Very strong 7,800 8,100 4,200

R11 Very strong 4,900 3,800 1,400

R134a 0.05 3,400 1,300 420

R12a No 8 0 0

Per fluoro-methane No 4,400 6,500 10,000

(Source International Panel on Climate Change 1994)

R134a is the currently used substitute for R12 in automobile air conditioning systems. R134a is a very good cleaning agent - it will remove deposited gums in the interior of the system. It is also very acidic if moisture is allowed into a system, and it needs special lubricants, because it is not compatible with the lubricant used in R12 systems. On the other hand,

R12a is a direct drop-in replacement for both R12 and R134a systems.

Because R134a is a strong global warming agent the government has decreed that all refrigeration systems must be built to 'contain' the refrigerant, for the lifetime of the system, i.e. the system must not leak. However it is by no means certain that this requirement is being met in current automotive systems. Conversely, it must be true that if a system will contain a freon, then it will also contain a 'natural' refrigerant.

The table (above ) illustrates the environmental benefits of using R12a. However it must never be forgotten that it is a very flammable refrigerant - although I personally know of no cases where R12a has been associated with a fire in an automobile - even as the result of a crash. There are three or more possible reasons for this:

1) the weight of refrigerant charged into the average automobile system is only about 12 to 16 ozs.

2) In the event of a sudden release of refrigerant only about half of the charge is released - the rest is retained for a short time in the oil in the system.

3) In the event of a slow release, the gas is heavy and will sink towards the ground where usually it will dissipate without problems.

However, it is extremely important that the air conditioning system be clearly labeled that it contains a flammable refrigerant. Many refrigerant technicians are not conversant with the properties of R12a - the name is too close to R12 to be comfortable (for me) - I think that this may lead to an accident.

Finally, although propane is used in Europe in many refrigeration type appliances, its use on this continent is being resisted by the freon manufacturers, and the current Canadian Standard (B52-95 Mechanical Refrigeration Code) is deficient in its treatment of flammable refrigerants. That is to say that its use may not be properly covered by insurance companies on the grounds that it is a flammable refrigerant.

If you need additional information I suggest that you talk to Mr. Lawrence MacNeil of HCTech Inc, Biggar Av., Hamilton, ON. L8L 3Z4. Phone 905-547-5693, Fax 905-547-3155. Their web site is www.hctech.com and e-mail is [email protected]

John Stephenson

[Cubes]

I've started to give this a go without removing the dash.

Any one have pics of all sides of the evaporator box?

The front half is seperating but its like the rear lower half is still attached by a screw.

argg

[predator]

yeah, not easy! I had trouble, even with the dash fully off..

I'm not sure what photos I have lying around, usually I'll have them - it's just a matter of finding them my home PC is knackered right now so no go for a day or two.

[Cubes]

Bugger..

Its definitely a dash out job as it 'looks' like i'll have to pull the aircon box out from the top?? I was hoping I could get away with it.

Ahh well I have a few dash globes to replace (clock etc).

I've put it back together for now until a week when I have more time to get stuck in to it.

There's a couple of warmish days from now until then so I cleaned the a/c evaporator as best as I could. It extremely caked full of of a dense dust.

Its amazing how much better the fan blows and how much more icy the a/c now is given now that the vents now blow my head off when on full. I cleared away a couple of rows so one can see what it is supposed to look like.

[predator]

I would say you're going to have to take it off, to get to the screws at the top properly, as I think they're top-down screws, and there are also ones around the side you may not be able to see from if you just take the glovebox out.

I am not sure whether you've already given it a shot, but you can actually take out the fan/spinny bit to clean as well. Mine was full of dirt/dust/japanese leaves, as that's the first point of entry to the rest of the system.

It depends what you're going to do, but if you need to replace the heater core anyhow, it sort of slides out of the back of the box (which goes to through the firewall to the coolant lines), and that requires taking the whole lot out.

I am not sure if R32 is similar to r33, but I know on 33 there are about 3-4 different types of heater-cores, and not all will fit the same box. So before you get one, make sure it's going to fit, and/or get the rest of the surrounding box as well to slot in.

If you muck with the AC evaporator and need to take that out for any reason, then, pssht, there goes all that gas... this one:

http://www.skylinesaustralia.com/forums/in...st&id=78309

is the one with the A/C evaporator in it.. Now that I remember -you should actually be able to get your fingers in and see the refrigerant temp sensor.. maybe even wiggle it around to fix the intermitant dropouts with the sensor. It may be embedded in a bunch of sticky foam type stuff you might need to peel off with your fingers.

[Cubes]

A/C evap doesn't need to come out. Just need to get to the heater core.

Fingers crossed I can remove the heater core without having to remove the a/c evaporator.