Problems Of Refrigeration Capillary Tubes And Their Remedies

The capillary tube is one of the types of expansion valves that are used in the refrigeration system.


If you want to know more about the types of expansion valves used in refrigeration systems you should check the article below.


You might like this: Refrigerator Expansions Valves: Functions and Types


Capillary tubes are mostly used in domestic refrigerators or small refrigerators that don’t have complex parts.


Though they are preferable because of the high efficiency they provide in small refrigeration systems, they also have their limitations.


In this article, I will share some of the problems one will experience when using capillary tubes and how you can fix them.


These are the problems of capillary tubes;

1. Fracture of the tube.

Fracture in the capillary tubes is one of the common problems when you put them into use.


You have to understand that the capillary tube will handle refrigerants of varying temperatures.


The liquid refrigerant from the receiver is likely to have a high temperature. At the beginning of the capillary tube, the temperature of the liquid refrigerant is going to be high, but as it progresses to the end of the tube the liquid refrigerant temperature is going to cooler.


The immediate change in temperature of the refrigerant is going to make cause fractures in these capillary tubes.


Also, by any chance the liquid refrigerant freezes in the capillary tube when the refrigerator is switched or damaged then it’s going to cause a fracture of the capillary tube.


The fractures of capillary tubes have to be fixed to prevent leakages of the refrigerant.


I will share the remedies for this issue at the end of this article, for now, let me continue to share the problems.


2. Blockage of the capillary tubes.

Blockage of the capillary tubes is another common problem that you will come across when you put them in use.


There can be several things that cause this blockage in capillary tubes.


The first thing that can cause blockage in these capillary tubes is the dirt and contaminants in the refrigerant.


Since the diameters of the capillary tubes are usually so small, the accumulation of dirt and contaminants will end up blocking the capillary tubes.


Dirty oil and moisture are other things that cause blockages in these capillary tubes.


The oil that is used in the refrigeration system to move the refrigerant smoothly within the refrigeration cycle usually ends up being dirty due to the dust and other contamination from the body being cooled.


If the oil is not removed from the refrigeration cycle in time, it will block the capillary tubes.


Moisture can also cause blockage of the capillary tube especially when it freezes within the capillary tubes.


When the capillary tube is blocked this will temper the flow of the refrigerant to the evaporator.


So this means that the evaporator will be starved and this will end up affecting the whole refrigeration process.


This is a problem that one should check on to ensure that the refrigeration system goes on effectively.


3. Internal scaling of the capillary tube.

Internal scaling of the capillary tube is another problem associated with this type of expansion valve.


The temperature differences of the liquid refrigerant, cooling and heating of the capillary tube will end up causing scaling internally.


Also, the refrigerant that ends up drying in the capillary tubes will end up forming these scales.


If the scaling keeps on increasing this will end up blocking the capillary tube and we will go back to the second problem.


Remedies of capillary tube problems;

1. Remedy of fracture in capillary tubes.

If there is a fracture in the capillary tubes the only solution that will work is to fix the fracture.


Without fixing the fracture then the leakage won’t be stopped and this means the refrigerant is going to be wasted.


The fracture in capillary tubes can be fixed by joining the fractures using a short length of copper tubing.


This will ensure that the fractures are closed by the short length of copper tubing.


It will be effective if the capillary tube doesn’t have many structures.


If the fractures are more, the only thing that one should consider is replacing the capillary tube.


Trying to fix the capillary tube with several short-length copper tubing is going to mess up the design of the capillary tube.


If the design is altered by any chance, the capillary tube won’t be effective.


2. Remedy of blockage in capillary tubes.

Blockage in capillary tubes can be fixed by heating the capillary tubes.


Heating the capillary tubes will melt any ice that is within the tubes, this will give room for the refrigerant to pass through.


If the water is the ice is melted, it’s then removed by the refrigeration driers.


Water is not good in the refrigeration system because it can end up corroding some parts of the refrigerator, reducing the oil viscosity and freezing in the expansion valves.


Also, heating the capillary tube will increase the viscosity of oil that blocked the capillary tube thus flowing away from the blockage point.


The oil can then be drained and another fresh oil can be fed into the refrigeration system.


If this solution of heating the capillary tubes won’t help then the capillary tube will have to be replaced.


It can be that the blockage is massive, and the heating can’t fix anything.


The good thing is that capillary tubes are available and cheaper in price compared to the other types of capillary tubes.


You might like this: Refrigerator Expansions Valves: Functions and Types


3. Remedy of internal scaling in capillary tubes.

Internal scaling of the capillary tubes can end up resulting in blockage if it’s not checked on early enough.


This problem of internal scaling in capillary tubes can be solved by blowing oil in a gas pressure onto the compression of the compressor.


The oil will end up being at a higher temperature while flowing through the refrigeration system.


The capillary tube will need to be disconnected from the inlet to the evaporator so as to allow the scales to fall off the tube.


This will get rid of the scales formed inside the capillary tube.


But if this method won’t work to remove the internal scales of the capillary tube then it should be replaced.


Final thoughts.


If you have tried to fix the problems on the capillary tube using the tips I have shared in this article and nothing worked then you should consider replacing the capillary tube.


Especially if the capillary tube has been in use for a long time. Some problems that you may encounter when using capillary tubes won’t be fixed by any of the remedies I have shared.


Another thing you should do if you want to maintain a capillary tube is to ensure regularly check it.


Also, make the habit of ensuring the oil used in the refrigeration is clean.


These are preventive measures you can take before the capillary tube is completely unusable.


If you have any questions, you should leave a comment. Thanks for reading. See you in my next article.


Related articles to check

  1. Refrigeration Evaporators: Functions, Types, Design Characteristics And Maintenance.
  2. Refrigeration Compressors: Function, Types, Advantages And Disadvantages
  3. Two-Stage Refrigeration Cycle Using A Flash Chamber: Working Principle
  4. Refrigeration Condensers: Functions, Types & Maintenance
  5. Vapour Absorption Refrigeration System: Working Principle

Leave a Comment