Refilling a split system: how to refill climate control equipment with freon yourself

A refrigerant leak is one of the most common causes of poor air conditioner performance.To fix the problem, you need to refuel the split system and check the tightness of the equipment casing.

It is better to entrust this procedure to specialists from the company with which the air conditioner service agreement has been concluded. Carrying out refueling yourself is quite difficult - you need to take into account a number of nuances of the technological process, and also have special equipment on hand.

We invite everyone interested in the issue to figure out how to prepare the device, control the amount of freon in the system and refill the air conditioner. Understanding the process will be useful to control the actions of the master or do the work yourself.

What do you need to know about refrigerant?

As a refrigerant in modern split systems Freon is usually used. This is a gaseous substance that, when compressed, turns 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 under overload, which will almost certainly lead to its early breakdown.

The mountings of the outdoor unit are quite capable of withstanding additional load, so it is most convenient to place electronic scales and a refrigerant cylinder directly on the housing

It should be noted that the cost of a compressor can be more than half the price of a new split system. Therefore, if you discover a lack of freon in the system, you need to check compressor and perform refueling 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.

A freon leak may 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 are no breakdowns, and air conditioner installation done correctly, within a year the amount of gas can decrease by 8-10%.

If the air conditioner has 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 quickly enough, most likely it needs refueling.

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

Frostbite on 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 charged with R-410A and R-407C freon. The latter is a mixture of three different refrigerants. It is this brand that cannot be added to the remaining substances in the system. The components of the composition evaporate at different rates, so when there is a leak, the proportions change.

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

The safer freon is, the more expensive it is. But you cannot use the wrong brand of freon for the sake of saving money. Information about which refrigerant is required for a particular device is indicated in its technical passport, as well as on the nameplate attached to the body of the outdoor unit.

How to prepare the device?

You can't just take a bottle of refrigerant, attach it to a pipe and let some of the substance into the system. The fact is that you first need to prepare the device for this operation. If freon flows out unnaturally quickly, the housing is most likely depressurized.

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 carelessly cut off the flared edge of a copper tube and forget about the need to restore the flaring. As a result, a leak occurs at the junction of the tube and the outdoor unit. Copper is a fairly soft material.

Before starting work, you need to clean the air conditioner unit from accumulated dust so that the fan can operate without additional loads and the most correct data can be obtained.

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

Additional information about possible air conditioner breakdowns and how to fix them is presented in this article.

Immediately before refueling, the system is drained. Nitrogen or freon is introduced into the circuit 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 charge a split system with freon yourself, you should remember that the amount of refrigerant should be sufficient, but not excessive. If there is too much gas in the circuit, the operation of the device will be seriously impaired, 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 the system is missing a few grams of refrigerant. Therefore, during refueling, it is necessary to organize control of the amount of freon entering the system.

They do this in the following ways:

• by measuring the change in mass of the refrigerant cylinder;
• taking into account the pressure in the system, which must reach a certain level;
• assessing the condition of the circuit through the sight glass;
• taking into account the temperature change at the indoor unit fan.

The easiest way to control the amount of freon is to record changes in the weight of the cylinder.To do this, before refilling, place the container with the refrigerant on the scale, reset the result and observe the change in indicators when the cylinder tap is open.

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

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

The device must meet the following requirements:

• load capacity - at least 20 kg;
• scale gradation - from 100 g;
• Availability of container weighing option.

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

Another available option is to bring the pressure inside the circuit to the desired level. To perform this type of filling, you will need a pressure manifold. Using this device, the pressure inside the system is assessed.

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

Before charging the system with refrigerant, it is necessary to find out why the leak occurred and then correct any problems found. Re-inspection is carried out after completion of work

A collector is quite expensive equipment that does not make sense to buy only to use once every few years. It will be useful not only at the stage of pumping freon, but also when draining and vacuuming 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 of observing the state of the refrigerant flow, monitoring the moment when air bubbles disappear from it. At home, the first two methods are often used.

Measuring temperature is a simple, but not very reliable method. When the fan circuit is full, 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, taking measurements periodically.

How to charge the air conditioner with refrigerant?

First you need to prepare the necessary devices and tools, such as a freon cylinder, 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 must be cleaned of dust to ensure proper 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. Place a container with freon on the scale.
5. Set the scale to zero and turn on the tare weight measurement mode.
6. Attach a vacuum pump to the circuit to pump out the remaining old freon, moisture, dirt, air, etc. from the system.
7. Connect a container with freon to the circuit.
8. Open the valve and observe the scale readings.
9. Close the valve and disconnect the container from the air conditioner.
10. Disconnect the hose and close the hole with the cap.
11. Check the system operation.

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

You can use a manifold with two or four positions, the latter is preferable since after evacuation you will not have to reconnect the hose intended 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.

After the cylinder is installed on the scale and its valve is open, you should immediately and just for a second open the liquid valve of the manifold to bleed the air lock

It should drop noticeably. At this point, open the pressure gauge for about 10 seconds and then continue to pump refrigerant into the system to the maximum pressure level.

After the initial air temperature drops by 12-14°C, refueling can be considered complete and testing of the system can begin.

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

To check how well the device works after refueling, it is recommended to turn it on and switch it 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, you should add a little freon. If the pipes are in order, the procedure can be considered successfully completed.

A few important nuances

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

The main technical characteristics of any split system are duplicated on a metal nameplate attached to the side wall of the outdoor unit of the device

This metal plate usually contains all the basic information about that particular model. Here you can find out what brand of freon is used to fill the circuit, what the pressure in it should be, 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 brand of refrigerant, as well as on the ambient temperature. If it is too cold or hot outside, and measurements are taken using a pressure gauge, an adjustment must be made. Data on pressure changes can be found in reference books.

When testing the air conditioner after refueling, you need to turn on only the cooling mode. If you accidentally start the heating, you can flood the compressor and completely break the split system.

Conclusions and useful video on the topic

Refilling the split system with freon:

How to top up 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 strictly follow the refueling procedure. But if you do not fully understand the process, it is better to ask a professional master for help and advice.

Do you have anything to add or have questions about refilling the split system? You can leave comments on the publication, participate in discussions and share your own experience in restoring the functionality of climate control equipment. The contact form is located in the lower block.