HVAC&R Tools Indispensable for Maintenance
The repair and maintenance practices of air conditioning or refrigeration equipment require precision instruments, because minimal errors can translate into loss of money, lack of comfort, damage to the environment or breakdown to the unit.
To make any connection to a team it is essential that whoever is going to carry it out has the training and the appropriate skills to execute a good practice that results in the optimal and efficient operation of the unit, avoiding second or third visits by the technician, which will have an impact on the mood and economy of the client.
A good preparation of the technician is accompanied by theoretical notions, but more important are the skills he has to exercise his activities in the field, which means having the knowledge regarding the diagnosis that must be made of an HVAC &R equipment and how to carry out its repair or maintenance.
At this point, the tools that the engineer or HVAC&R technician must use to perform activities such as: detecting leaks, analyzing the gas load, executing the recovery of refrigerant gas, applying autogenous welding, among other activities, come into play.
For the implementation of these different actions, the industry has placed at the disposal of technicians, a series of tools, which if at first could be somewhat rudimentary, have now evolved significantly, offering greater comfort and security in their use, in addition to transmitting more accurate results with little margin for error.
Today the manufacturers of these instruments have turned all their design engineering development towards the digital age, allowing a quick and better reading of measurements.
The HVAC&R industry is influenced by many fields of studies such as thermodynamics or physics, which have their foundations in precise numerical calculations with the aim of ensuring that what is embodied in a paper is properly applied to reality.
It is of the utmost importance that people engaged in the repair or maintenance of refrigeration, air conditioning or heating equipment, know the instruments that should be used; know how to use them and adapt to the changes and technological innovations of measurement provided by the industry to facilitate the work, make the tasks safer and provide greater accuracy of calculations.
In the next lines, instruments and tools that cannot be missed by a technician or engineer who carries out connections in HVAC&R equipment will be detailed, since these will ensure optimal results, but always taking into account that the person must have the appropriate training and be constantly updated.
Recovery equipment (recuperator, tank and scale)
Recuperator: It is a machine that connects to the HVAC&R system and the gas recovery cylinder depending on the method to be used (gas phase recovery, liquid phase recovery, Push/Pull method, liquid and vapor method).
This machine will extract all the liquid and gaseous refrigerant from a system, to leave it free and susceptible to being charged or recharged again.
Recovery tank: It is a cylinder that must meet DOT specifications. They are recognized because the small ones (13.6 Kg. and 22 Kg) are painted on the shoulder area of the tank and the rest is gray. It should be noted that only gas recovery tanks are identified to use used refrigerants, so cylinders should not be used for new refrigerants and much less disposable ones.
This tank consists of a "Y" valve, which has two inlets, a red one for liquid refrigerant and a blue one that is for the gaseous, so at no time should the hoses be reversed and there is no need to make a mixture of gases.
Scale: This will be used for the weighing of the recovery tank, which should not be loaded beyond 80% of its capacity, so the technician must have a calculator on hand to determine not to exceed that delimiting percentage
In the market there are conventional scales, but you can also find electronic scales type portfolios that through a screen allow the cylinder to be loaded to 80% of its capacity, without exceeding it.
Torque meter
It is a tool that is used in the adjustment of nuts or screws in an appliance. It is worth noting that this should be used every time a manufacturer indicates a specific torque value, which could be indicated by a table or in a manual, in such a way that the torque force necessary to tighten a screw in a piece of equipment is applied.
The torque meters have a graduated scale, in which it is possible to predetermine or read the applied torque value according to the type of torque meter. When this scale does not match the units in which you have the torque specifications, it is necessary to convert the specification to the units in which you have the torque meter scale.
On the other hand, there are also digital torque meters that through a display indicate if the torque measurement indicated by the manufacturer of the product being adjusted has already been reached.
Not using this tool could cause leaks in the refrigeration compressors through the joints, or also leaks in the mechanical seals, causing the screws to slit their throats due to excessive tightening or being loose.
Phase sequencer
They employ an electrical circuit with no moving parts. Connecting the device to the network illuminates a green pilot when the sequence of phases is correct, or a red one if it is inverted.
Today there are phase sequencers that provide clear indications of three-phase systems through an LCD screen, in addition to determining the direction of rotation in order to indicate the correct connections. They indicate the sequence of phases and offer a frequency and voltage range (up to 700 V) suitable for commercial and industrial applications.
Checking the phase sequence is crucial for certain three-phase loads, whenever they must be connected to the electrical system. Incorrect connection of the three-phase motors of the air handlers and Scroll compressors results in reverse rotation and as a result irreparable damage to the Scroll compressor or the incorrect operation of the air handler. Checking the phase sequence and rotation before commissioning ensures the correct and safe connection of electrical equipment in three-phase systems.
Hook ammeter
It is a well-known tool in the world of electricity, but it is also used in the HVAC&R industry because the units work with electrical energy.
The hook ammeter consists of a device that has tongs, as well as a screen, in which the parameters of current intensity in a line will be detailed digitally.
Thanks to the hook ammeter, technicians avoid the inconvenience of having to open the circuit in which they want to measure the current to place a classic ammeter, guaranteeing greater safety.
Currently, the market offers multiple varieties of models and brands, so their ranges vary according to the capacity handled by the hook ammeter, because in low voltage they can range from 60 to 1200 amps.
Thermometer
This instrument is used to measure temperature. Since they were invented, thermometers have evolved considerably and their function has diversified to different areas, since many processes require the control of the temperature factor.
In the field of HVAC&R, digital infrared thermometers are currently being widely used, which are manufactured by several companies, however their function remains the same: they instantly and accurately measure the temperature of the surface where it is pointed, without the need to make a contact. These produce a bright laser beam that hits a surface, being very useful for areas where access is difficult or which are dangerously hot.
The use of these tools, as well as others that we will see in the next part of this article, will undoubtedly guarantee trained field technicians a more accurate work with positive results.
Pivot Extractor Valve
It is very useful for extracting pivots in the case of recovering refrigerant gas. If you are recovering from a system that has these types of valves, you should try to remove the pivots from all valves. Another function it has is that it serves to change the defective pivots that can cause leaks in the cooling system, avoiding the overflow of large amounts of refrigerant. This valve is connected, closed and the pressure gauge can be attached to it.
Leak detectors
Leak detectors are instruments that allow you to locate the source of refrigerant gas emissions within a cooling or air conditioning system.
Electronic: This tool is a small console that carries an extension in the form of a hose or tube that sniffs refrigerant gases. This hose is passed through the entire HVAC&R system and in the event of a leak in some area of the system, it will let the operator know by emitting a sound or light signal.
Propane gas flame: A propane cylinder is taken whose flame is blue, to which a rubber hose will be connected which must travel throughout the cooling system and in the case of detecting the presence of refrigerant, it will cause the change of color of the flame to green.
Fluorescent tracer: It is based on the use of a contrasting medium, which is a liquid that changes color when applying violet light. This contrasting medium is placed inside the system and makes the path of the lubricant, which circulates through it. Once all the equipment is completely impregnated, a violet light lamp will be used and supported with amber lenses, the technician will easily detect the leak, since the liquid will take on a different color where there is the gas leak.
Soapy water: This is the oldest method to detect leaks and consists of placing soapy water throughout the system to determine the leaks from the bubbles produced by the soapy water.
Autogenous or oxyacetylene welding equipment
This is the method of melting copper pipes from a refrigeration or air conditioning system in which acetylene and oxygen are used to create strong, precise and cleaner bonds.
Oxyacetylene welding equipment is composed of two tanks, one intended for oxygen and the other for acetylene. Both are joined by a regulator which is a kind of manometer that will indicate to the operator the indices in which the gases are being used.
The equipment also has hoses through which gases will circulate from the cylinders to the torch. It is recommended that the hoses have clamps and these must have a specific color according to the gas used.
The torch consists of a metal extension that will adhere to the hoses and which will be one of the final routes through which the gas will circulate before becoming a flame, since the last point is the nozzle of the torch where the flame will come out that will make welding possible.
Within the welding equipment, it must be remembered that the operator must have the appropriate protective clothing.
Vacuum pump
The vacuum pump is a device that is connected by hoses to the system and begins to lower the internal pressure of the system, to such a level that it modifies the boiling point, which causes the water to boil and evaporate at room temperature.
The pump is responsible for sucking the gases and vapors to expel them to the outside. On the other hand, if you do not have a vacuum meter, you run the risk of not reaching the correct vacuum or lowering the pressure of the system so much that the boiling point of the oil could be modified, causing it to begin to boil or, under certain conditions, be expelled to the outside of the system. That is why it is very important to emphasize: the correct vacuum is achieved by measuring and not by the time left by the pump working in the system.
It is advisable to make the vacuum after having verified that the circuit does not leak gas. Also, to quickly remove moisture during the vacuum process, you can previously do a sweep with gaseous nitrogen, opening low and high pressure valves, as well as heating the system using lamps.
Pressure gauges
The pressure gauge is an instrument for measuring pressures of gases and liquids. In the refrigeration sector, a set of two pressure gauges is used consisting of a smaller scale to measure the suction pressure and a larger scale to measure the discharge pressure.
It is usually built by a bellows that stretches with the pressure and that at one end actuates a needle that marks the measured pressure. They currently exist in electronic format.
It can be calibrated in mm or inches of mercury in a column; or in Kg/cm² or lb/inch² and usually carries the temperature-pressure scale of the refrigerant gas to be measured.
The pressure gauges are connected to the system through flexible hoses, which must respect a color code and through which gases or liquids will circulate.
VACUUM GAUGE
It is an instrument used by refrigeration and HVAC technicians to effectively measure the vacuum in a system. Because the pressure gauges used for multiple services cannot measure vacuum microns, it is necessary to use this instrument that has taken on special importance with the presence of polyolester-type oil.
Vacuum gauges measure the pressure in the installation's pipes during and after a vacuum process. They always indicate the absolute pressure (the zero point corresponds to the absolute vacuum). In the market there are already different electronic vacuum gauges which in addition to being resistant, do not need calibration.
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