Recovery of R134a

[ClimateChange67]

Hi Guys,
Was advised to join this site as I was told it was a invaluble source of information!

Why I find myself here is I am due to venture on a 3 day Vehicle Air Conditioning course and I have rightly or wrongly begun to purchase all the tools etc required...very determined to succeed!

I have a basic understanding of how the system works etc but this may sound very odd to the experienced of you out there but I just cant get my head around the recovery process. I understand how it`s all set up (Will be using 4 way manifold gauge) etc but the issue I have is... the recovery unit I purchased (JET FP2167) states that it can recover most gases including R134a but says that a different method is utilised for recovering liquid. Now I don`t know if I am being pretty daft or something but I thought refrigerant was part liquid and part vapour at certain stages of it`s journey around the system???

I was under the understanding that I would be able to recover the refrigerant from the out port on the Recovery unit direct to a recovery cylinder but the manufacturers details say that if recovering liquid I would have to use 2 cylinders?

I guess what I am trying to get at is what is the actual difference between gas recovery and liquid recovery as I thought that R134a was indeed a gas when it left the cylinder and would be recovered as a gas therefore eliminating this confusion I have embarked on!

I am sure I will learn everything I need to know in the next couple of weeks but I would truly appreciate someone who would be able to make sense of what I am saying so I can enter the course I am doing with some degree of knowledge. :confused:

Cheers guys!

[Rob White]

.

Do not think of refrigerants as gas. Gas is very dry and superheated.

Gas is what we call all vapours. Air is gas.....

Refrigerant can be in 1 of 3 (4 actually) states

Solid
Liquid
Vapour
(and gas)

In refrigeration we only use the two states, Vapour and Liquid.
When you are removing refrigerant you can do it in vapour or liquid form.

So the recovery machine says you can recover liquid and what that means is
if you set the machine correct it will pull the refrigerant out in liquid form.

All recovery machines will pull vapour out, so you just need to be aware of
what state the refrigerant is in when you recover it and that is where the training
comes in.

Moving liquid is a heck of a lot faster than moving vapour (gas)..
So most new machines are set to pull both out.

Regards

Rob

.

[ClimateChange67]

Cheers Rob,

Thanks for the reply!

So...that would mean that when I recover the R134a I will have to use the 2 cylinder set up as although my Jet FP2167 states it can indeed pull both vapour and liquid but when recovering liquid the seals etc would deteriate long term so that is why the manufacturer advises the use of the 2 cylinders.

So I guess I must recover the R134a with 2 cylinders i.e, from the manifold gauge set to the liquid port on the cylinder (Open) then from the vapour port (Open) to the recovery unit then from the recovery unit to the second cylinder with vapour port closed and liquid port open.

Sound about right or have I got it confused again!

Once again, cheers Rob!

[monkey spanners]

You won't need two cylinders for doing cars, just suck it out the low side connection with the system off and you'll only get vapour out, in fact chances are you'd only get vapour out the high side too.

If you do get a bit of liquid through to the reco machine its very unlikely to kill it, not blown mine up in eight years.... but am careful to restrict the flow by using the tap if there is any liquid.

I suggest you go and study a diagram of a fridge system and learn what states the refrigerant is in in various parts of the system when its running, the knowledge would be helpful to you with questions like this and also helpful to any customer you will have in future assuming this is a business venture.

http://www.youtube.com/watch?v=w17DpGCcRj8&feature=related

http://www.youtube.com/watch?v=2wZb6HgIDE0&feature=related (http://www.youtube.com/watch?v=w17DpGCcRj8&feature=related)

[ClimateChange67]

Cheers Monkey Spanners!

I have been studying pressure Enthalpy etc and must admit to the inexperienced, at first glance...confusing to say the least!

I am getting to understand the cycle and what process takes place although like you said I would only require one cylinder to evacuate the R134a and that is what confused me on looking at the manufacturers operating instructions regarding the 2 cylinder method.

I will continue to study and I really do appreciate your reply...makes the confusion alot easier to stomach.

All the best fella!

[cadwaladr]

one important thing to remember paramount is that the reclaim cylinder can take the amount you are recovering and that is of the correct type,i always vacuum the cylinder overnight and always filter it on both sides of the recovery machine,also scales and labelling.

[ClimateChange67]

Cheers cadwaladr,

Thanks for your reply...I have the receovery cylinder which is labelled and also have the scales (CPS 700) which fortunately measures the weight in and out automatically (Will still be watching the manifold set & scales though) so should be straightforward enough. Do, to some degree understand that side of things.

Like I have said previously, I think the manufacturers instruction booklet confused me somewhat as I have seen many a post on the internet of which none pictured the above mentioned system recovery using the 2 cylinders.
Monkey Spanners reply cleared up the confusion with his post.

All the best and really do appreciate your imput!