Refueling split systems: how to fill freon climate equipment with your own hands

Alexey Dedyulin
Checked by a specialist: Alexey Dedyulin
Author: Elena Pykhteeva
Last update: May 2019

Refrigerant leakage is one of the most common causes of poor air conditioning. To fix the problem, you need to refuel the split system and control the tightness of the equipment case.

It is better to entrust the implementation of this procedure to the specialists of the company with which the contract for maintenance of the air conditioner is concluded. Refueling yourself is quite difficult - you need to take into account a number of nuances of the process, as well as have special equipment at hand.

Everyone interested in the matter, we suggest to figure out how to prepare the device, to control the amount of freon in the system and to refuel the air conditioner. Understanding the process is useful in order to control the actions of the wizard or do the work yourself.

What you need to know about the refrigerant?

As a refrigerant in modern split systems usually use freon. This is a gaseous substance that, when compressed, transforms into a liquid state. Passing along the internal circuit of the device, freon absorbs thermal energy. In the outdoor unit, it gives off heat to the surrounding air.

An important part of the system is the compressor, which constantly interacts with the refrigerant, compressing it to a liquid state. If there is too little freon in the circuit, the equipment will work with overloads, which will almost certainly lead to its early breakdown.

Freon outdoor unit refill
The mountings of the outdoor unit are quite capable of withstanding the additional load, so it is most convenient to place the electronic scales and the refrigerant bottle directly on the case

It should be noted that the cost of the compressor can be more than half the price for a new split system. Therefore, having discovered a lack of freon in the system, you need check compressor and refuel as soon as possible.

If the performance of the air conditioner has dropped, it has become slower to cool the room, most likely it is time to check the amount of refrigerant in the circuit.

Freezing of freon can also be indicated by freezing of the outer pipe of the circuit. Very often refrigerant leaks due to depressurization of the system.But even if there is no damage, but air conditioner installation performed correctly, during the year the amount of gas may decrease by 8-10%.

If the air conditioner worked flawlessly for several years, split service was carried out in accordance with the manufacturer's recommendations, and then the unit began to cool the room not fast enough, most likely, refueling was needed.

But it’s not always possible to simply add a small amount of refrigerant to the system. Some types of this material must be completely removed from the circuit, and then filled with new freon.

Split system frostbite
Frostbite of the ends of the copper tube and condensation on it is a clear sign that there is not enough refrigerant in the system

Most often, modern air conditioners are filled with freon of the R-410A and R-407C brands. The latter is a mixture of three different refrigerants. It is this brand that cannot be added to the residual substance in the system. The components of the composition evaporate at different speeds, so the proportions change with leakage.

This does not apply to R-410A freon - a more modern version, which is used in the latest models of split systems. Compositions R-407C and R-410A do not harm the environment, unlike Freon R-22. It represents the composition of past years, the use of which is not recommended due to harm to the ozone layer.

The safer the freon, the more expensive it is. But for the sake of economy, you can not use the wrong brand of freon. Information about which refrigerant is needed for a particular device is indicated in its data sheet, as well as on a nameplate attached to the casing of the outdoor unit.

How to prepare the device?

You can’t just take a bottle of refrigerant, attach it to the tube and let some amount of material into the system. The fact is that you first need to prepare the device for this operation. If freon leaks unnaturally quickly, most likely there is a depressurization of the case.

Copper tube split system
Leakage may occur at the junction of the copper tube with the outdoor unit due to improper installation and damage to the flared edge

You need to find out the cause, eliminate it, and only then let a new portion of gas into the system. The tightness of the circuit is also checked when it is necessary to replenish the refrigerant lost during operation. Very often, a leak occurs after inept installation.

For example, some inexperienced craftsmen inaccurately cut the flared edge of a copper tube and forget about the need to restore rolling. As a result, a leak occurs at the junction of the tube with the outdoor unit. Copper is a fairly soft material.

Outdoor unit cleaning
Before starting work, you need to clean the air conditioning unit from accumulated dust so that the fan works without additional loads and you can get the most correct data

It is possible to damage the rolling, even without cutting the tube, screw fasteners unevenly enough. Therefore, before refueling the split system, you need to unscrew this connection and check the condition of the tube edge. If it is damaged, it should be cut, flared and screw fastened. In this case, you should act carefully, the nut should go easily, without effort.

Additional information on probable breakdowns of the air conditioner and methods of their elimination is presented in this article.

Directly before refueling, the system is drained. Nitrogen or freon is introduced into the circuit in order to displace foreign substances from it. At high pressure, the device is carefully inspected in search of a gap from which gas flows. Sometimes it is advisable to use an ultraviolet lamp.

Methods for controlling the amount of freon

When figuring out how to fill the split system with freon yourself, you should remember that the amount of refrigerant must be sufficient, but not excessive. If there is too much gas in the circuit, the operation of the device will be seriously disrupted, since the refrigerant simply will not have time to evaporate.This can seriously damage the compressor.

This situation is worse for the device than if several grams of refrigerant are missing in the system. Therefore, during refueling, you need to organize control of the amount of freon entering the system.

Do this in the following ways:

  • measuring the change in mass of the refrigerant cylinder;
  • given the pressure in the system, which should reach a certain indicator;
  • assessing the condition of the circuit through the sight glass;
  • given the temperature change in the fan of the indoor unit

The easiest way to control the amount of freon is to record the change in weight of the cylinder. To do this, before refueling, the refrigerant tank is put on the balance, the result is zeroed and the performance changes are observed with the cylinder tap open.

As soon as its weight decreases by the required amount, refueling is immediately stopped. Of course, this method is only used to completely fill the circuit. If you just need to refuel the system, then first you need to find out the weight of the refrigerant that is already inside, and at home it is difficult to do.

There are professional scales designed for these purposes, but many masters do with inexpensive household models.

The device must meet the following requirements:

  • carrying capacity - not less than 20 kg;
  • graduation of the scale - from 100 g;
  • the presence of the option of weighing containers.

It is most convenient to use electronic scales, which make it easier to track the change in the weight of the refrigerant tank.

Another option available is to bring the pressure inside the circuit to the desired value. To perform such refueling, you will need a gauge manifold. Using this device, the pressure inside the system is estimated.

The refrigerant is supplied to the circuit in small portions, constantly checking the pressure information with the standard indicator, until a match is reached.

Checking the operation of the split system
Before filling the system with refrigerant, it is necessary to find out why there was a leak, and then eliminate the detected problems. Re-verification is carried out after completion of work

The collector is quite expensive equipment that does not make sense to buy to use once every several years. It is useful not only at the stage of freon injection, but also during the drainage and evacuation of the system. You can borrow such a device from a familiar master or rent it at a specialized point.

The sight glass method is available to professionals. It consists in observing the state of the refrigerant flow, tracking the moment when air bubbles disappear from it. At home, the first two methods are often used.

Temperature measurement is a simple but not very reliable method. For a fan with a filled circuit, the temperature should usually be about eight degrees, although there are models for which this figure is five, a deviation of a couple of degrees is allowed. The refrigerant is introduced in small portions, periodically making measurements.

How to charge air conditioning with refrigerant?

First you need to prepare the necessary devices and tools, such as a freon bottle, scales, manifold, thermometer, vacuum pump, etc.

In general, the procedure for refueling a split system on a scale is as follows:

  1. First, the radiator blocks need to be cleaned of dust to ensure the correct operation of the fans.
  2. Remove the cap from the large tube on the outdoor unit.
  3. Connect this outlet to the manifold hose.
  4. Install a freon container on the balance.
  5. Set the balance to zero and turn on the tare mode.
  6. Connect a vacuum pump to the circuit to pump out the remains of the old freon, moisture, dirt, air, etc. from the system.
  7. Connect a freon tank to the circuit.
  8. Open the valve and observe the balance.
  9. Close the valve and disconnect the container from the air conditioner.
  10. Disconnect the hose, cap the hole.
  11. Check system operation.

When refueling with temperature measurement, you need to set the average mode for the fan of the indoor unit and start the device in cooling mode to a temperature of 18 ° C. Record temperature readings and data from the pressure gauge.

Manifold for refueling a split system
You can use the collector in two or four positions, the latter is preferable, since after evacuation you do not have to reconnect the hose designed for additional equipment

If the outside temperature is 25 ° C, then the normal pressure level in the circuit should be 4.2-5 bar.

When the pressure reaches its maximum, the air temperature is measured again.

Freon cylinder on scales
After the cylinder is mounted on the scale and its valve is open, immediately and for just a second, open the manifold liquid valve to bleed the air plug

It should drop markedly. At this point, the pressure gauge is opened for approximately 10 seconds, and then the refrigerant is continued to be pumped into the system to the maximum pressure level.

After the initial air temperature drops by 12-14 ° C, refueling can be considered completed, you can start testing the system.

Vacuum pump
A vacuum pump designed for this type of work must have a pressure gauge as well as a check valve to prevent particles of oil from entering the circuit.

To check how well the appliance works after refueling, it is recommended to plug it into the network and switch to the minimum cooling mode. If after about a quarter of an hour the pipes begin to freeze, it means that there is too little refrigerant in the system, a little freon should be added. If the pipes are in order, the procedure can be considered successfully completed.

Some important nuances

Before starting work, it is necessary to study the data sheet of the air conditioner and the instructions that are attached to it. If these documents are lost, you should definitely pay attention to the metal nameplate mounted on the outdoor unit.

Specifications split system
The main technical characteristics of any split system are duplicated on a metal nameplate mounted on the side wall of the outdoor unit

This metal plate usually has all the basic information for this particular model. Here you can find out exactly which brand of freon is used to fill the circuit, what should be the pressure in it, how many grams of refrigerant need to be pumped into the system, etc.

It should be remembered that the nominal pressure in the circuit depends on the type of refrigerant, as well as on the ambient temperature. If the street is too cold or hot, and measurements are taken using a manometer, an adjustment must be made. Data on pressure changes can be found in reference books.

When testing the air conditioner after refueling, only the cooling mode must be turned on. If you accidentally start heating, you can fill the compressor and completely break the split system.

Conclusions and useful video on the topic

Refueling a split system with freon:

How to refuel the circuit:

Fueling a split system yourself is difficult, but quite possible. To do this, you need to choose the appropriate method, find the necessary equipment and follow the refueling procedure exactly. But if there is no full understanding of the process, it is better to ask a professional master for help and advice.

Is there anything to supplement, or have questions about refueling a split system? You can leave comments on the publication, participate in discussions and share your own experience in restoring the operability of HVAC equipment. The contact form is located in the lower block.

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Visitors Comments
  1. Gennady

    I had a problem with a crack in the copper tube, freshly charged freon came out in 2-3 days. I have all sinned on refuellers that they only take money, and do not refuel as it should. Until one clever master said that the crack should be fixed first.
    And the fact that it’s much cheaper to refuel it myself, I realized when I went shopping for refrigerators, there any type of freon is several times cheaper. Only large volumes, it is necessary to buy a lot of rhinestones, it stops.

    • Danil

      Gennady, well, I can imagine how much negative the workers are constantly experiencing, albeit not always straightforward. Obviously, there are problems with the device itself if the substance escapes from there. Well, it's cheaper or not cheaper to buy freon. But for some reason there are people who are professionally engaged in this, which means that not everything is so simple. I do not recommend everyone to engage in amateur activities, otherwise there will be cracks in the tubes later.