In detail: an electric air compressor 220v DIY repair from a real master for the site my.housecope.com.
The compressor is a rather complex technical equipment, as it is used, it has the right to wear out and break down. In this article, we will consider all the methods of maintenance and operation to maximize its life. Execute DIY compressor repair, if he still broke, perhaps.
The reliability of compressor equipment largely depends on timely and quality maintenance. A large number of piston compressor breakdowns are the result of poor-quality cleaning of the compressed air (abrasive dust, water, and other inclusions). Application and timely replacement and cleaning of filter elements will delay compressor repair for a long time.
The main reasons why a reciprocating air compressor fails are:
- Unfavorable operating conditions
- Scheduled maintenance is not performed
- Not competent service personnel
To ensure high-quality maintenance, operation and repair of the compressor with your own hands, it is necessary to solve all the above points.
The main difference between maintenance and compressor repair is that during repairs, certain parts are forcibly replaced, and during maintenance, parts are replaced as needed, depending on their actual condition.
A compressor is a device for increasing the pressure and moving gas to the required source (spray gun, grinders, wrenches, airbrushes and any other pneumatic equipment). The main equipment in demand in body repair has become a piston compressor, oil type. In piston, the volume of the working chambers is changed by means of reciprocating pistons.
They have a different number of working cylinders and distinguish them according to the following structural arrangement:
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- Horizontal
- Vertical
- Opposed
- Rectangular
- V and W shaped
- Star-shaped
Before doing compressor repairs with your own hands, you need to study its technical structure. The photo below shows a diagram of a single-stage compressor, piston group.
- Crankshaft
- Frame
- Connecting rod
- Piston pin
- Piston
- Cylinder
- Valve
- Cylinder head
- Valve plate
- Flywheel
- Oil seals
- Crankshaft bearings
On the case near the electric motor there is an automation unit called a pressure switch. It can be used to adjust the compressor. It is possible to lower the pumped pressure or increase it.
If any defects are found (the appearance of knocking, jamming of rubbing parts, strong heating, increased consumption of lubricant, etc.), it is necessary to make repairs.
It is important to establish the definition of the type and volume of repairs at the stage of diagnosing the state of the object before repairs. Compressor malfunctions can be divided into two groups: technical malfunctions (working part of the piston group and malfunctions of electrical equipment). Below are the most common breakdowns:
- Compressor (motor) does not start
- The electric motor hums and does not rotate
- Compressor not picking up speed
- Knock in the cylinder-piston group
- The cylinder is too hot
- Performance has dropped
- Strong vibration
The compressor will not turn on, the most common problem.The main and trivial thing that can be in this breakdown is that there is no voltage in the network. The first thing to check is the plug and wire for an open circuit supplying the electric motor. Using a special “tester screwdriver”, check whether all phases are energized. Check the fuse, if present. Make sure that the starting capacitors are working (for single-phase compressors, the voltage is 220V).
Pay attention to the pressure level in the tank (receiver). Perhaps the pressure is sufficient and the automation does not start the compressor, as soon as the pressure drops to a certain level, the electric motor will start automatically. This is not a breakdown, many people forget about this nuance and worry ahead of time.
The check valve can also become a problem if the compressor does not turn on. Also, a faulty automation unit (pressostat) affects the breakdown (on, off), the button on the unit itself may have become unusable.
If the electric motor does not start, hums, hums does not pick up the required speed, or stops during operation, this does not always mean its breakdown.
The main malfunctions of the electric motor that can interfere with its correct uninterrupted operation:
- Low motor power (insufficient mains voltage)
- Loose connections, poor contact
- The check valve is out of order (leaking), thereby creating back pressure
- Incorrect starting of the compressor (see operating instructions)
- Piston group jammed (due to lack of oil level, overload)
If the electric motor of the compressor does not turn on at all and does not make sounds, then this indicates the following:
- Mains supply fuse tripped
- Overload protection tripped
- Poor electrical connection (wiring problems)
- The worst thing is that the electric motor burned out (there is often a characteristic smell)
One of the reasons for compressor breakdown is a faulty piston group. It is quite easy to recognize a defect in this system. They are usually accompanied by thumping, crashing, grinding and other sounds of a metallic nature. If the compressor knocks, then its discharge part is faulty, where there are many metal parts that interact with each other. Due to their friction and wear, there are extraneous noises and unpleasant sounds.
You should not start with such a breakdown; if possible, it should be eliminated as soon as you heard the first signs of their manifestation. The main faults if the compressor starts to knock and work loudly than before:
- Crashed bearings, connecting rod bushings
- The bearings on the crankshaft are out of order.
- Worn out piston, rings, finger on the piston
- Cylinder worn out
- Loose cylinder and head bolts
- Solid particle hit the cylinder
- The cooling impeller is loose on the pulley
To repair these breakdowns, in simple cases, it is enough to stretch all the bolts and nuts. If the piston, cylinder, crankshaft or connecting rod are worn out, then a comprehensive overhaul is required. When repairing a piston group, it may be necessary to bore the cylinder, if it is badly worn and has external defects, select a repair piston according to new dimensions. Possible piston system defects are listed below:
- Changing the diameter of the piston, cylinder
- Distortion of the shape of the cylinder mirror
- Risks, scratches, scuff marks on the cylinder walls
- Cracks in the main working part
- Flange cracks and breakage
With prolonged operation, due to wear, risks appear on the cylinder mirror, the inner diameter of the bushing under the eccentric shaft increases. During repairs, the cylinders are restored by pressing the sleeves into them. Worn bushings for the eccentric shaft are replaced. This repair is quite difficult to do with your own hands without the necessary tools and equipment.Since the most time-consuming and responsible stage is the restoration of the cylinder. Boring is performed on a vertical boring machine using a special device.
As far as the cylinder is concerned, below we will consider the main malfunctions of the compressor crankcase.
- Cracks in the walls of the crankcase cavities
- Deviations in the size and shape of landing sites
- Warping of seats
- Crashed seats for crankshaft bearings
When these units are worn out, they must be replaced with new ones. The hole for the bearings is bored on a horizontal boring machine for a larger bearing diameter or for pressing the bushing, followed by boring the pressed bushing to the required diameter. Repair of a compressor of such complexity should be performed by qualified specialists.
Below, spare parts "repair kit" for the overhaul of the compressor, piston group.
If the compressor is very hot, then this signals some kind of malfunction. There can be several reasons for overheating. Starting with a simple one, it is blocked the airflow to the cylinder and the crankcase. Check if the impeller is covered by foreign objects.
One of the main causes of a heating compressor is a lack of oil level. Working units work for wear, high friction is created as a result, it gets very hot. With further such work, the equipment will quickly fail. Check the oil level, if it is not enough, it is necessary to top up to the correct level.
Valve failure due to carbonized contamination or loosening. There may also be clogged air passages.
Look at the pressure level, it is possible that the automation has broken down and the compressor “threshes” to a high pressure, and this causes overheating. The safety valve may need to be repaired or replaced.
The drop in performance can be due to several reasons. Clogged, clogged air intake filter. Remove and clean the filter with compressed air or replace it. Mostly in reciprocating compressors, it is made of regular foam.
It is possible that there is an air leak somewhere. Inspect all incoming and outgoing tubing and hoses. As in the previous case, wear and malfunction of the valves are possible, this greatly affects the performance. With a sufficiently long use, the piston rings wear out, the sealing disappears. In more serious cases, the cylinder and pistons are worn, scratched or have other external defects, which leads to loss of compression and the compressor stops pumping air.
It is worth checking the tension of the belt connecting the electric motor and the crankshaft of the piston system. When loose, slippage is possible and the compressor stops pumping air properly.
If oil gets into the working chamber, bad enough signs, of course, this will not lead to complete failure of the compressor, but it can very much harm the painting work and the occurrence of defects during painting. The main reasons for oil getting where it does not need: Filled with low viscosity oil, that is, the oil is too liquid, it seeps through the seals and rings. The oil level is too high. Due to the excess oil, it is squeezed out with force and enters the chamber. Incorrect oil used. Fill with special compressor oil only.
The piston and rings in the cylinder block are worn out. Also, the wear of the cylinder itself affects the ingress of oil into the working chamber. To eliminate the malfunction, it is required to repair the compressor of the piston group, which are described above.
A reciprocating compressor, like any technical equipment, requires certain maintenance. Proper use will help extend the life of your compressor equipment. Consider the main activities for the maintenance, repair and operation of the compressor.
1. Replacing and cleaning the air filter.The filter element is mainly made of non-woven material, foam rubber or synthonin. If the compressor is located in the same place where the car is painted, then it becomes heavily clogged (sticks) with dust from paint, varnish and other paint and varnish material. The filter prevents abrasive dust from entering the cylinder, the piston and cylinder wear less. Change and clean the filter as often as possible, as this will significantly increase the resource and delay the repair of the compressor.
2. Oil change is a very important point. Watch the oil level on a special indicator (window) in the compressor crankcase. Operating at a low level or without oil will result in major overhauls. Top up to the required level if it is not enough. Periodically, it is necessary to completely drain and fill in new. Use only special compressor oil. Oil for piston compressor Mobil, Fubug, Shell VDL 100, КС 19, 46 or any other branded oil.
3. Condensate drain. An important point in compressor maintenance. The air is saturated with moisture, it inevitably enters the receiver with the intake air. Over time, it accumulates in large quantities. With a high content of condensate, it can be thrown into the air hoses, which leads to defects during painting. Also, due to condensation, corrosion begins inside the receiver. Drain off condensation as often as possible, at least once a week, especially during hot and humid seasons.
4. Monitor the general condition, periodically blow out dust and other contaminants. Pay special attention to the impeller on the electric motor, cylinder fins, air cooler, as they are used, dust and paint dust adhere to them, which reduces the cooling capacity.
5. Inspect the belt drive for wear and tension. When pressing on the belt at the midpoint, it should not bend by more than 12-15 mm. Broach all nuts and bolts. Periodically check the function of the safety valve, which serves to protect against overpressure due to a breakdown of the pressure switch.
Follow all of the above methods and you will delay the repair of the compressor for a long time.
The main purpose of an air compressor is gas compression and continuous supply of a jet of air under pressure to pneumatic equipment and pneumatic tools. Such air is an energy carrier and ensures the operation of spray guns, airbrushes, wrenches, and a tire inflation gun. 
air compressor
The listed pneumatic tool is safer to work with than a power tool, for example. The pneumatic equipment cannot have a short circuit that can lead to electric shock and fire. That is why such a tool is widely used in car repair shops or when repairing a car with your own hands.
The air compressor is applicable to households and when it stops working, it needs to be repaired. However, the repair of compressors is not particularly difficult, it is quite possible to do it yourself.
To understand the problems of a compressor, you need to clearly understand what elements it consists of and what they are intended for. The compressor, in the minimum configuration, consists of a blower (an engine that creates an air flow) and a receiver - a container that contains compressed air. Reciprocating compressors are most commonly used.
One of the main requirements for a compressor is its safety. If the pressure in the receiver is not controlled, the compressor will burn out. There is a high probability that the receiver cylinder may explode. To prevent this, the receiver is equipped with an electronic relay that automatically turns off the compressor when the air pressure reaches a certain value.
The air compressor is equipped with a pressure gauge that indicates the amount of air pressure in the cylinder.A check valve is used to protect the compressor from negative influences. Its main function is to prevent air from returning back to the compressor when the unit is turned off or otherwise interfered with.
More complex compressor designs are characterized by additional equipment such as compressor automation. Typically in small compressors, the automation unit maintains a pressure of up to eight atmospheres using a pressure switch, turning on or off the power to the electric motor when the minimum or maximum pressure in the receiver is reached.
In this case, there are two pressure gauges: the large one shows the pressure in the tank of the receiver, the small one - at the outlet. The pressure switch can be equipped with an unloading valve. When the unit is stopped, it will open, making it easier to start the engine later.
In some models, a cooling radiator is provided on the pipes for supplying air from the compressor to the receiver.
Cooling the air results in less condensation in the receiver. Such a trifle in the design extends the service life of the automation.
The presence of a drain valve allows you to quickly drain condensate from the receiver, because it is advisable to end each operation of the unit with this operation.
The safety valve releases the increased pressure in the receiver, if for some reason the automation does not work, which protects the compressor motor from overloads.
The air filter protects the piston system from sand, dirt, paint fumes.
The following types of compressors are distinguished:
- Volumetric action - keep gas or air in a confined space, increase pressure. Among them are:
- rotary, principle of operation - suction and compression of gas during rotation of the plates; the working volume decreases, this leads to an increase in pressure.
- piston - pressure is created by the movement of pistons and valves; reliable in operation, but noisier than rotary ones.
- Dynamic - provide compression by increasing the speed of gas movement, increasing its kinetic energy, which is converted into compression energy. Distinguish:
- centrifugal - used for air exchange in mines;
- axial or axial.
Consider how a piston-type compressor works, air or gas in it is compressed by a piston that moves through the cylinder:
- When the piston (3) moves up the compressor cylinder (4), the working gas is compressed. The electric motor moves the piston through the crankshaft (6) and connecting rod (5).
- The suction and discharge valves are opened and closed by gas pressure.
- The diagram on the left shows the gas suction phase into the compressor. When the piston moves down, a vacuum is created in the compressor and the inlet valve (12) opens. Thus, the gas enters the compressor space.
- The right diagram shows the gas compression phase. The piston moves upwards and the outlet valve (1) opens. The gas leaves the compressor at high pressure.
scheme of work
The blower itself produces an uneven air stream, which cannot be used, for example, for using a spray gun. The receiver saves the day by smoothing out the pressure pulsations.
Having replenished the stock of information about the compressor unit, you can repair the compressor yourself. A distinction is made between the following compressor system malfunctions:
- The compressor unit blower does not start.
- From time to time, the thermal cut-out is triggered.
- When the compressor starts, the thermal cut-out is triggered and the fuse is blown out.
- The engine of the unit runs, but does not pump air into the receiver, or does it slowly.
- When the supercharger is turned off, the pressure in the receiver drops.
- High moisture content in the air outlet.
- Strong vibration from the engine.
- The compressor unit works intermittently.
- The air flow is consumed below the norm.
There are several probable reasons why the compressor will not start..
If the unit does not start and does not hum, check the supply voltage with an indicator screwdriver. If there is a phase, the connections of the plug to the socket are normal, it is worth checking the fuses that are subject to melting.
Defective fuses are replaced with others of the same rating. New fuses with higher current ratings must not be installed. If the fuses blow repeatedly, there may be a short circuit at the input to the circuit.
The compressor may not start due to incorrect operation of the pressure control switch or failure of the level settings. To check if this is so, the gas is released from the cylinder and the supercharger is started. If the engine is running, readjust the relay. Does not work - change the required part.
The engine will not run when the thermal cutout trips, turning off the power due to an overload of the piston system. In this case, do-it-yourself compressor repair is to let the motor cool down for 20 minutes, after which the unit will return to normal operation.
It happens that thermal protection is triggered regularly. This happens due to low voltage in the network or increased air temperature in the room. The voltage in the network must not be less than the lower limit of the range recommended by the manufacturer; it is enough to measure this value with a multimeter.
In a poorly ventilated area, an air-cooled piston engine often overheats. The solution is to move the compressor to another well-ventilated room.
The blower inlet filter may become clogged due to poor air flow, in which case it should be flushed or replaced.
The problem is more serious if the thermal protection is triggered when the compressor starts and the fuse blows. Perhaps it is not designed for the power of the unit, then it is replaced with the appropriate one.
The fuse can be blown due to an overload in the mains. It is worth checking and disconnecting some of the consumers that load the network. Repair of air compressors is difficult if the voltage relay does not work correctly or the bypass valve breaks down. In this case, it is best to seek help from a workshop or service.
If the voltage in the network is too low, the electric motor of the compressor will not cope with the scrolling of the axis and will hum. It is worth checking the voltage in the network with a multimeter (must be at least 220V).
If the voltage is normal, there may be too much pressure in the receiver and the piston cannot push the air. To eliminate this malfunction, manufacturers strongly recommend that you set the switch to the "OFF" position for 15 seconds, and then move it to the "AUTO" position.
If such actions do not lead to a positive result, it is likely that the receiver pressure control switch is malfunctioning or the control valve is clogged.
A defective relay should be sent for repair or replaced. You can try to fix the check valve by removing the cylinder head and cleaning the channels.
A drop in pressure indicates an air leak from the system. It happens:
- in the blowing path;
- in the outlet valve of the receiver;
- in the control valve of the piston head;
It is necessary to carefully check the entire pipeline with a soapy solution, covering the entire pipeline. If a leak is found, it should be sealed.
The vent valve may leak air if not closed tightly or due to a malfunction. If the tap is closed and the soapy solution is bubbling, the part must be replaced.
The problem may be with the piston head valve. In order to carry out further repair of the air compressor, it is necessary to disassemble the cylinder head and remove the dirt that may have collected in the valve.Before starting work, it is imperative to bleed all the compressed air from the receiver. If the pressure drops again, the valve needs to be changed.
The air supplied from the compressor can be very humid in the following cases:
- moisture has accumulated in the receiver;
- the air intake filter is very dirty;
- the compressor is located in a room with high humidity.
To combat moisture, the following methods are applicable:
- you should regularly drain the excess liquid from the receiver cylinder;
- the filter element is washed or replaced;
- the unit is transferred to another room, where the air is drier or special filters are installed.
Reciprocating engines are prone to high vibration. Don't worry until the vibration becomes too noticeable. It can be assumed that the reason is the wear of the vibration cushions, which are easily replaced.
The vibration can be caused by loosening of the bolts. In such a case, repairing the air compressor is a simple matter of tightening the bolts.
Interruptions in the operation of a compressor unit are caused by:
- Defective pressure control switch. The air pressure switch for the compressor is used to automatically protect the unit in the following cases:
- the suction pressure becomes less than the calculated one;
- the discharge pressure exceeds the permissible limit.
Distinguish low pressure switch, the direct actuation of which (opening of the contact) occurs when the pressure drops to a controlled value. When the pressure rises by the setting value, reverse operation occurs (contact closure).
Have high pressure switch direct actuation (opening of the contact) occurs when the pressure rises to the set value. Reverse operation (contact closure) occurs when the pressure drops.
The pressure switch is being repaired or replaced with a new one.
- Intensive extraction of compressed air - occurs due to a discrepancy in the performance of the compressor unit
with power consumption. These compressor malfunctions can be excluded if, when buying a pneumatic tool, you thoroughly study its characteristics and find out how much air is consumed per unit of time.
Such a malfunction occurs due to a gas leak in the high pressure system, as well as if the air intake filter is clogged. Air leakage can be avoided by stretching all butt joints and wrapping them with sealing tape.
