Power Tronics Domestic Refrigeration & Rent-A-Fridge

Does your Fridge lose Gas ?            PART ONE

So why exactly do fridges & freezers lose their refrigerant (gas)?

For some people this may not make sense at first, but try to form a picture in your mind as we go through a basic discussion, and you may find this article, and others that follow, very informative.

 Getting Started with a few Basics.                                                 

The gas in any refrigeration system, is in a closed or sealed system. This means that no refrigerant is supposed to leak out, and also no moisture is supposed to enter the system. This simply means that no refrigerator unit can ever use it's refrigerant (gas) up. The refrigerant is simply re-used to allow the correct cooling to take place on a continuous basis, and nothing ever gets used up ..... unless your electricity, of course.
All refrigerators have two parameters within which they operate, being electrical and gas respectively.
If the electrical system never gives any problems, and the gas section does not lose any refrigerant either, well then ideally we will have a fridge that would last a lifetime. ................Your lifetime.
Let's forget about the electrical side for a moment, because we all know what problems can occur when Escom or Municipal power supplies go on the blink.........................

We have already learnt that the gas in the system does not get used up, which thus means that it must obviously leak out of the system somehow,........... but how, and where?
Let's go back to the Biology Lab. at school to prove this theory........
Take a fair size party baloon and inflate it to it's maximum holding capacity. Now tie two or three decent knots to the open end to prevent the baloon from deflating. Next, place this baloon in a safe place and monitoir it's size for a few days.

10 days later, and you will see that the size of the baloon has changed. --- It has become smaller ----- WHY has this happened?    Has it leaked at the knots?    NO... It has leaked through the wall of the baloon through a process known as "Osmosis"
Osmosis, as some of us learnt in Biology, is when molecules from one structure may pass through a permeable surface to another structure. The operative phrase here would be permeable surface. "Permeable being the same as porous or a pervious surface.  Not very suitable to absolutely prevent any substance from possible leakage.
If we can understand the concept of the deflating baloon over a period of time, then the loss of gas from the refrigeration system is no different.
The piping within the refrigerator system is either Steel, Copper or Aluminium. Since both Copper and Aluminium are very costly metals to use, because they chase the cost of producing the appliance through the roof, the manufacturers are in agreement with one another that this is a very bad idea, since they are in the business of producing and selling fridges as cheaply as possible. (which,"by the way", is not so cheap nowadays.)
When water and steel are present, they soon get a little helper "rust". As we all know, "rust"soon does it's bit by quickly corroding and pitting any metallic object in sight.

fig. 1.

Here we have an internal gas leak which has to be cut open, and found from the outside....

fig.2.

Finaly the damaged pipes become visible.

fig. 3.

Here one can clearly see how rust has badly damaged piping, causing a gas leak.

These pipes are also enclosed in polyurethane, which has now also become waterlogged and very soggy.

Having temp problems with future video for this space........................................

Now this is the sick part.................
 Remember that each appliance comes with a lifetime warranty ...... No you've got it all wrong, this is not your lifetime, but the lifetime of the appliance ......... even if this appliance, only in some instances, barely makes it throught a 12 month warranty period, well that's good enough for the manufacturer, because when you and I try to lay claim to our valuable warranty when things go wrong , we usually hear the words "Sorry, your appliance is out of warranty". Doesn't it just make you completely mad?

High and Low pressure piping.

The refrigerator has two pressure sections in the gas piping, these are more commonly known as the "High" and "Low" pressure circuits. Very easy way to remember, is that High pressure pipes are usually fairly hot to the touch (around 40 Deg C - 60 Deg C), and are mostly visible or mounted on the rear surface or the bottom of the appliance.
Low pressure pipes on the other hand are the opposite. They reach temps. as low as - 25 Deg C to about - 40Deg C, and are usually mounted within the cooling compartment or may even lie within the inacessable inner walls of the appliance. There is always a very damp or wet situation around these pipes.  i.e. they rust or corrode very easily. (see fig. 3. above.)

Where would my fridge be most likely to leak gas from?

We now know that mostly steel piping is used for both high and low pressure systems.
We also know that high pressure pipes are exposed to the atmosphere, and run much hotter than those with a low pressure, which are also enclosed within a wet or very moist environment.
Common Logic shows us that heat and open air, drives away moisture and a potential rust environment.
From this we can clearly see that almost all refrigerator gas leaks will therefore be found in the low pressure piping or within the moist walls of the cabinet. This is a "scientific fact".
The fact that steel piping rusts in the presence of moisture is just where our experiment about osmosis comes into play.
The wall thickness of the steel piping is compromised, because it now becomes thinner and slowly, yes ever so slowly, the internal refrigerant pressure begins escaping through the damaged walls of the steel piping.

Now we can see just how it is possible for the system to begin losing Gas.

So why am I feeding you the reader all this jargon about osmosis  and pressures and hot and cold piping........?    SIMPLY - Put, dear reader, to hopefully save you some money in the long run.
So read on because your fridge will not last until the the end of your lifetime as Grandma's did.