DIY aircon top up.

I have put this together to try to help those who wish to top up the aircon in there cars at minimal cost.

First a word about safety. The liquid gasses used can give you frost bite, so please wear eye protection, and cotton gloves under surgical gloves or similar. You carry out this work at your own risk.

Finding R134A "the refrigerant used" in small quantities without PAG oil is the first problem. After smoe research I found products used by plumbers to freeze pipes is readily available at plumbing and builders merchants,and just happens to be R134A two such products shown below in picture. 1 Freezer spray used to cool electrical components is also R134A.

EZfreeze make an aerosol for topping up aircon systems but the oil used is under no circumstances suitable for the Prius gen2 or 3 but the hose and gauge will work perfectly. Pic2

Ezfreeze aerosol has a special threaded top to take the hose. Pic3

The differences in the types of nozzles can be seen in Pic4

If you carefully pull off the nozzles you can see that two of the cans have the same valve mechanism under the nozzles. Pic5

I found that the EZ nozzle will fit the red aerosol in the pictures. Pic6

This will now take the EZ hose Pic7 and will top up the aircon in the Prius, the instructions for this will be given towards the end of the post.

For those people that do not have the hose or cannot easily obtain one do not give up. You can adapt the aerosol of either type fairly simply by two different methods as follows.

The first method requires a little ingenuity.Take a compressor adaptor used for blowing up air beds, beach toys ect rap around the tapered end of this some PVC electrical tape to build up it's diameter to about 3/8inch. The small hose that comes with the aerosol can should be a snug fit in the middle if not glue it in with an epoxy glue or silicon sealant. Pic8

Alternative method, find a short bolt "about 1/2inch long" that will screws into the low pressure port. I think this is 6mm fine thread, but check on your vehicle. Drill through the centre of this bolt from end to end a 1/8inch hole, do not be concerned if the hole is no dead in the middle. The small hose that comes with the aerosol can shuold be a snug fit if not glue it in with epoxy glue or silicon sealant. Sorry no picture.

Now to the actual topping up. First check your car still has some pressure in the system. If you are using the EZ hose connect it to the low pressure port between the engine and inverter. Gray cap with an L centre of Pic9 some pressure should show on gauge. See next paragraph.

If you are not using the EZ hose check to see if there is pressure in the system by pressing the centre pin of the low pressure valve "like you are letting a tyre down" with a small screw driver just a quick press. If there is pressure all's well, if not your system may have a leak and also may have air in it. If you wish to continue no harm will be done by trying to refill but coolant may be wasted, or system may not work efficiently.

I am making the assumption that the ND11 oil in the system does not need topping up at this stage. If it does need topping up do this before topping up the R134A but instructions for topping up the oil will be at the end of this post.

Using the EZ hose connected to the low pressure port Pic9 and your aerosol can put the car in ready, turn on the aircon max cold, all vents open, fan on full and car doors open.


Operate the aerosol can in short bursts "about 1second" while watching the sight glass next to the high pressure port "gray cap with H" Pic10. If the compressor was not running to start with when the pressure rises it should start. Keep adding the gas and you should begin to see frothing in the sight glass, do not rush this keep adding gas in short bursts until the frothing stops and bubbles appear stop adding gas. The gauge may read in the green or not but the sight glass is a better guide to correct pressure.

Turn off the aircon and frothing should occur in the sight glass if it does you are done, if it does not you have over filled the system and will need to let out some gas. This should be avoided if possible because you may also let out some of the oil.

For those using the home made hoses the tape rapt part of the adapter should be screwed into the low pressure port with a pair of mole grips or similar so that the thread inside the port grips the tape tightly. Push the small hose into the aerosol can and operate as for the EZ hose taking care not to over fill. The low pressure valve will open it's self with pressure from the aerosol.

For those using the bolt type adapter screw the bolt into the low pressure port, but not far enough to open the valve. Then connect to the aerosol and proceed as above.

ND11 oil can be obtained from Interdynamics and can be added by using a 1/2 dia or smaller syringe by using either of the two home made adapters and substituting the syringe for the aerosol can before adding gas. Dependant upon the pressure left in the system and the diameter of the syringe " the smaller the better " the pressure to inject oil on the end of the syringe can be up to 20LBS.

 

Yes I agree with your statement and that is why I put in the part about having some residual pressure, as most systems loose some pressure over the years. This is really aimed at systems without major leaks.

My own system was topped up by the Toyota agent in May 2010 at a cost of £89 or $145 just done it myself around £5 or $8

 

Well spotted, actually my finger is numb after typing all that as well as my brain.

 

The refrigerant used R134A is listed as non harmful. The containers I show are normally used for basically spraying onto a water pipe to freeze it so that the pipe can be cut without draining the water inside, a full can may be used to freeze one pipe. The R134A then evaporates into the atmosphere.

The other common use is for freezing electrical components if a circuit becomes thermally sensitive to find the faulty component, again it is vented strait to the atmosphere,

I know this is also done in the US because when I was working over there I saw this method of fault finding being used. So putting it in aircon is much more friendly.

Another point is aircon top ups are available both hear and in the US such as those made by Interdynamics, the only real difference in what I am using is there is no oil or leak sealer in those products.

John.

 

In Europe R12 is no longer available and I believe it is illegal to use. R134A I have found is used in many different product including air dust cans, pharmaceuticals "for inhalers", for paint ball guns and wine bottle cork removers.

In the UK because of our temperate climate, aircon in cars has only really taken off in the last ten years. It was available before then but was usually an expensive extra. Very few houses hear have aircon, government statistics say only 125,000 homes most with portable equipment.

 

You will not believe how far removed my cottage is from your planned set up. I live in an oak timber framed cottage with lath and plaster panels inside and out, built around the year 1550 it is what is known in UK as a "grade2 listed building" this means even though I own the building I cannot alter it in any way without the permission of English Heritage. If I do alter it without permission I could be heavily fined or even go to prison.

For heating I have a wood burning stove no radiators but I would not give it up with the views of the English countryside for anyone.