Do-it-yourself circulating pump repair step-by-step instructions

In detail: do-it-yourself circulating pump repair step-by-step instructions from a real wizard for the site my.housecope.com.

Circulation pumps of various types are often used today in country houses and summer cottages, which makes it possible to make the operation of autonomous heating systems more efficient and at the same time save on energy resources. Meanwhile, if such a hydraulic machine fails, the entire heating system ceases to function, which puts its user with a choice: use the services of qualified specialists or repair the heating circulation pump with his own hands.

Dismantling the circulation pump

The reasons for the breakdown of circulation pumps, the types of which differ from each other in certain design features, are associated both with non-compliance with the rules for operating such equipment, and with the quality of the coolant, drops in the power supply network, as well as with a number of other factors. Before deciding on an independent repair of the circulation pump, you should understand well the design and principle of operation of such a device, which will allow you to establish the exact cause of its failure and eliminate it.

Without knowing the design of the circulation pump, you will not only be able to repair such a hydraulic machine, if necessary, but also engage in regular maintenance. The design of circulation pumps is:

a body made of stainless steel or non-ferrous alloys;
an electric motor, the shaft of which is connected to the rotor;
directly the rotor itself, on which the wheel with blades is installed - the impeller (its blades, which are constantly in contact with the pumped medium, can be made of metal or polymer materials).

Video (click to play).

Circulation pump design

The circulation pump operates, regardless of its design, according to the following principle.

After the electric current is supplied, the shaft of the drive motor begins to rotate the rotor on which the impeller is installed.
The heat-transfer fluid entering the inner part of the pump through the suction branch pipe is thrown by the impeller and centrifugal force to the walls of the working chamber.
The liquid, which is subject to centrifugal force, is pushed into the discharge pipe.

As mentioned above, depending on the design features, the circulation pump for heating can be of different types. So, devices with a rotor are distinguished:

In private houses, the most commonly used circulation pumps are "wet" type

For circulation pumps of the first type, which are used mainly for equipping domestic heating systems, the rotor is constantly in a liquid medium. This not only contributes to the lubrication of the moving parts, but also to their efficient cooling. The main advantages of this type of equipment include:

low noise level during operation, since the water in which all the moving elements of such a device are located perfectly absorbs vibrations;
ease of installation (such pumps simply cut into the pipeline), maintenance and repair.

Meanwhile, pumps with a "wet" rotor, if we talk about their shortcomings, are not very efficient, can be installed only in a horizontal position and are very critical of the lack of liquid in the heating system.

Dry rotor pumps are installed in separate boiler rooms and are used in systems that heat large areas

The drive motor of pumps with a "dry" rotor is placed in a separate unit. Rotation from the motor shaft is transmitted to the impeller by means of a special coupling. Unlike devices with a "wet" rotor, pumps of this type are characterized by a higher efficiency (up to 80%), but also by a more complex design, which somewhat complicates the procedures for their maintenance and repair. Circulation pumps with a "dry" rotor are cut into the pipeline and their body is fixed to the wall, for which a special console is used.

In order not to face situations in which the circulation pump installed in the heating system will require repair, it is necessary to strictly follow the rules for operating such equipment, which are as follows.

If there is no water in the pipeline, it is impossible to start the circulation pump.
The value of the generated water pressure must be within the characteristics specified in the technical passport of the circulation pump. If the device produces a reduced or, conversely, an increased water pressure, this can lead to its rapid wear and, accordingly, failure.
During the period in which the heating system is not used, the pump must be turned on for circulation at least once a month for a quarter of an hour, which will prevent oxidation and blockage of its moving parts.
It is very important to ensure that the water temperature in the heating system does not exceed 65 °. In water heated to a higher temperature, a precipitate begins to actively form, which, interacting with the moving parts of the hydraulic machine, contributes to their active wear and, accordingly, the failure of the entire device.

It is necessary to inspect the circulation pump and check the correctness of its operation on a monthly basis. Such measures make it possible to identify malfunctions in the operation of equipment at the initial stage and promptly take appropriate measures.

Periodic inspection of the circulation pump will significantly reduce the likelihood of its failure during the heating season.

Checking the circulation pump for correct operation includes such actions as:

switching on the hydraulic machine to the operating mode and checking the level of noise and vibration generated by it;
checking the pressure (pressure level) of the coolant created in the discharge pipe (as mentioned above, the fluid pressure must be within the values given in the technical data sheet);
control of the degree of heating of the engine, which should not be too high;
checking for the presence of grease on the threaded connecting elements of the pump and applying it if it is absent;
checking the presence and correctness of the grounding of the body of the hydraulic machine;
checking for leaks both on the pump body and in the places where it is connected to the pipeline (if leaks are present in such places, it is necessary to tighten the threaded connections and check the integrity of the installed gaskets);
Inspection of the terminal box and check if the wire is fixed in it (in addition, it is necessary to check whether moisture gets into the terminal box, which is unacceptable).

The main reason for the rapid wear of friction bearings in pumps is considered to be the increased contamination of the coolant.

It is possible to single out several of the most typical malfunctions for circulation pumps, which are quite realistic to eliminate with your own hands. Such malfunctions can be identified by their characteristic signs, without even disassembling the pump and without using complex diagnostic equipment.

A situation where the pump is noisy but the impeller is stationary is often caused by oxidation of the drive motor shaft. This can happen due to the fact that the hydraulic machine has not been used for a long time.To repair the heating pump with your own hands with such a malfunction, you must perform the following steps:

disconnect the power supply;
drain all water from the pump and the adjacent pipeline;
by unscrewing the corresponding screws, dismantle the drive motor together with the rotor;
resting on the working notch of the rotor with a hand or a screwdriver, turn it by force, moving it off the dead center.

Disassembled circulation pump

The pump will make noise, but it will not work even if a foreign object gets into its inner part, which blocks the rotation of the impeller. To repair the circulation pump in such a situation, do the following:

turn off the power supply;
drain water from the pump and the adjacent pipeline;
disassemble the pump according to the above scheme;
remove a foreign object;
a strainer is installed on the inlet pipe.

This is how the body of the circulation pump looks from the inside.

If the switched on circulation pump does not make noise, but also does not work, there may be problems with the power supply. To identify the cause and eliminate such a malfunction, disassembling the circulation pump may not be required: using a tester, they check the level and presence of voltage at the device terminals. In many cases, to eliminate such a malfunction, it is enough to correctly connect the pump to the power supply.

If there is a fuse in the design of the circulating pump, then it could burn out during a voltage drop in the mains, which can also be the reason why the heating pump does not work and does not make noise when it is turned on. To restore pump operation, simply replace the blown fuse.

Armed with a tester and a schematic diagram, you can find more serious breakdowns in the electrical part of the pump, for example, burned out windings

In the event that a layer of lime deposits has formed on the inner surface of the stator, the running pump will periodically stop. To solve this problem, it is necessary to disassemble the pump and clean all its internal parts from lime deposits.

The reason for the loud noise of the equipment when pumping liquid can be the presence of a large amount of air in the pipeline. To eliminate such a problem, it is enough to bleed air from the pipes. In order not to face this in the future, you can install a special unit in the upper part of the heating system circuit, which will automatically release air from the pipeline.

If the housing of the hydraulic machine vibrates strongly when pumping the coolant, this may indicate that the bearing, which ensures the rotation of the impeller, is severely worn out. Repair of a circulation pump for heating in this case consists in replacing a worn bearing.

End graphite bearing of the "Grundfos" pump

Among the reasons for the discrepancy between the fluid pressure and the standard values at the outlet of the centrifugal pump are the following.

The impeller is rotating in the wrong direction.
The phase conductors in the terminal box are incorrectly connected (with three-phase connection).
The viscosity of the heating medium used is too high.
The filter installed on the suction line is clogged.

The specified issue is corrected according to the cause that caused the issue.

The causes of such a malfunction may be incorrect connection of the phase wires in the terminal box, bad or oxidized contacts in the safety assembly of the device.

To repair the electronic component of the pump, you will need basic knowledge of electrical engineering.

This is another nuisance that occurs quite often during the operation of such equipment. Why is the circulation pump heating up? The reasons may be different, but such a situation always indicates that your equipment is operating under increased load.

Thus, many situations in which the circulation pump does not work or does not work correctly can be dealt with on your own, without resorting to the services of qualified specialists and without purchasing expensive spare parts and components for repair.

Before the start of the heating season, in order not to subsequently face the failure of the circulation pump and its repair, it is necessary to properly prepare the device for a long period of intensive work.

It is necessary to check the correctness of the pump insertion into the pipeline, referring to the arrow on the housing and the impeller rotation indicator. When installing a new pipeline for installing a circulating hydraulic machine, it is better to choose a section directly in front of the boiler, where the risk of air congestion is minimized.
Grease must be present on gaskets and pump nozzles to prevent drying out.
Check the condition of the suction strainer and, if clogged, thoroughly clean it.
It is also required to evaluate the correct connection of the pump to the power supply, for which a tester is used.
Check the tightness and reliability of the hydraulic machine connections.
It is necessary to perform a test run, the results of which will show whether your equipment is ready for the heating season.

Before disassembling the circulation pump, if it becomes necessary (for example, during repairs), it is necessary to disconnect it from the power supply and remove it from the pipeline by unscrewing all fastening threaded elements.

After the pump has been dismantled from the heating system, you can start disassembling it:

The cover is removed, which is fixed to the pump body with special bolts.
After removing the cover, the impeller is removed from the inside of the pump.

After that, access to all internal parts of the pump will be provided, they can be inspected, cleaned or replaced with new ones, if necessary.

The sequence of disassembling circulation pumps of various models for repair is very well demonstrated by videos that are easy to find on the net.

Owners of autonomous heating know that a circulation pump is needed for normal circulation of the coolant.Private houses are mainly located far from service centers or workshops, so it is worthwhile to master the repair of a circulation pump with your own hands.The pump, like other equipment, needs maintenance. To prevent breakdowns, you must follow these recommendations:

In summer, when the device is not working, it must be turned on at least once a month for 15 minutes. But at the same time, the device should not run dry: if the pipes are currently empty, they simply pump water from one container to another, connecting the unit to them with hoses. This procedure will prevent oxidation of the shaft surface and prolong bearing life.

During the heating season, attention should be paid to the operation of the device from time to time. Has the unit started to make noise, vibrate, or other signs of malfunction? Is the circulation pump not getting too hot? After all, the early stage of the malfunction is much easier to eliminate than the neglected one.

If there is a coarse filter in the heating system in front of the pump, then it is periodically checked for rust or other contaminants.

Do not forget about the lubricant and check its sufficient availability in the provided places.

General arrangement of the circulation pumpCompliance with all operating rules of the device does not guarantee the uninterrupted operation of the unit. Breakdowns may occur that do not depend on human actions: a filter clogged, voltage drops, etc.If the engine does not turn on, but the pump does not generate hum or other strange sounds, it is worth checking the fuse.It reacts sharply to power surges and melts when the engine is threatened, thereby opening the electrical circuit. In this case, the fuse will have to be replaced, after which the device will return to normal operation.If the failure was not in the fuse, check the power cable, the circuit breaker in the junction box, and the electrical wiring. The wire section or switch may need to be replaced.After checking the wiring, it is worth moving on to the winding of the electric motor. Its serviceability is checked by measuring the resistance. The multimeter should read 10-15 ohms. Some units are equipped with a starting winding with a resistance of 35-40 ohms.If the multimeter displays "infinity", then the winding is out of order. And when the readings are closer to zero, an inter-turn closure happened. In this case, turning on the device is accompanied by the fuses in the panel blown.Circulation pump testingModern devices have a low noise level, so often the owner of such a unit cannot understand - is it working or not? To diagnose the device, use the indicator tester of the rotation of the circulation pump shaft, which will show without a power supply whether the device is working properly. To do this, you need to bring your indicator to the motor shaft and the scale will show whether the shaft rotates or does not work at all.When the circulation pump hums, but the shaft with the impeller does not rotate, it is worth immediately turning off the unit, because the motor winding may burn out. There are several reasons for this malfunction:

The shaft does not work due to downtime during the summer. For the same reason, the impeller sticks to the casing. In this case, it is necessary to disassemble the device and manually turn the shaft. Manufacturers took this moment into account, so a notch for a screwdriver is made on the shaft.

The impeller does not rotate due to a foreign object in the chamber. After removing it, the system will resume.

If the device makes unusual noise during operation, it may be trapped air in the system. For removal, it is recommended to install an automatic air vent on the heating circuit. But if it is not there, then the air is vented manually.
to the menu ↑The device temperature must match the temperature of the heating medium pipes. If it rises higher, it means that errors were made during installation, or improper operation takes place. The circulation unit can heat up for the following reasons:New generation circulation pump device

initially incorrect installation. It is not difficult to determine the problem: the pump heats up at the initial stage, immediately after installation.

blockage in the system. With prolonged operation, deposits and rust accumulate in the pipes, which leads to a decrease in the water passage. The device is overloaded to ensure normal circulation of the heating medium. At the same time, the engine overheats, but unscheduled maintenance can cope with the breakdown.

foreign body. With slagged communications, pieces of rust or plaque break off from pipes and radiators, which, when they get into the device, jam the electric motor. If the device is not disassembled and cleaned in time, the coils of the electric motor may well fail and the device will simply stop turning on.

lack of lubricant for bearings. With an insufficient amount of lubricant, the bearings are poorly lubricated and wear out quickly, which leads to a reduction in the service life of the unit as a whole. If the engine is seized as a result, the pump is dismantled and returned to the service center.

low voltage in the network. At a voltage below 220 V, the electric motor overheats and quickly fails. In the first minutes of overheating, it is worth checking the voltage in the network with a voltmeter, because the problem may not be in the pump.

One of the problems that happens with heating units is the operation of the pump without pumping water.There are four reasons for this condition:

air ingress or water leakage, which is eliminated by repairing holes and cracks in pipes;

incorrect regulation of the heating system. The malfunction is solved by checking the correct position of the taps (primarily to the pump);

no water. It is worth repairing such a malfunction by supplying water to the device.

Blocked or stuck valve. To eliminate it, the valve should be repaired or replaced.

To repair the circulation pump, it must be dismantled and disassembled. Dismantle the device according to the following scheme:Dismantling the circulation pump

The unit is disconnected from the power supply. In order to disconnect the cable from the terminal box, it is necessary to remove the case from the power supply unit of the device.

Shut off the liquid supply with the side valves and drain the remainder in the system.

The device is unscrewed with a hex screwdriver, but suddenly the bolts have become attached, they are moistened with a special WD liquid, and after 20-30 minutes they try to unscrew again.

After dismantling, the unit cover is removed. Under it is a rotor with a wheel and blades. Basically, the rotor is secured with clamps or bolts. After removing it, access to the inside of the device opens. By carefully examining the pump, malfunctions are detected and eliminated.
to the menu ↑

Follow the instructions below:

1. Unscrew the bolts that secure the mechanism cover. Don't forget to use a liquid key!
2. Remove the cover. The rotor is located under it. Its fastening is most often done with bolts. Less commonly, special clamps are used.
3. Unscrew the bolts (release the locking elements).

Disassembly of the pump is complete. All units and individual parts of the circulation device are located under the rotor. It is not necessary to disassemble the pump down to the bolts. First, you should decide which element is out of order, and only then remove the specific part that needs to be replaced or repaired. If the entire pump needs to be replaced, simply dismantle it. It is not necessary to completely disassemble the mechanism. Remove the equipment that has failed. Install a new one in its place.

Pumps from different manufacturers have been shown to have the same design. Therefore, their faults, as a rule, are the same. Many users are faced with the fact that the circulation device starts to hum when starting, but the rotor does not rotate. A similar problem occurs due to:

Incorrect connection of electrical wiring or lack of power on the terminals of the pump. The problem is solved by checking the power supply with the tester and reconnecting (correct!) Cables.
Oxidation of the motor shaft. This phenomenon is most often observed in cases where the pump has not been used for a long (several years) time. Do-it-yourself repair in such a situation will be as follows - turn off the power, drain the water from the pipeline and the pump itself, disassemble the electric motor (remove the cover and rotor). Now the main thing. You need to take a screwdriver and turn the rotor all the way into the working notch. The operation can also be performed by hand if the mechanism rotates without difficulty.
Foreign objects falling into the mechanism. You need to disassemble the cover and rotor. Remove foreign body. After that, be sure to replace the mesh filter. As a rule, a foreign object will disable it.

Circulation device in the heating system

If the pump starts up normally and then stops, it is most likely not properly connected to the terminals. Check it out. Make a proper connection if necessary.Another reason for the described breakdown is the appearance of scale between the rotating units of the mechanism. Disassemble the unit, remove the existing limescale, lubricate the joints of all parts with oil. Sometimes the pump stops due to a loose fuse. It is necessary to dismantle this element and clean the clamps securing it.

A defective fuse is often the reason the pumping equipment will not turn on.

Check the terminals, measure the voltage at the terminals with a multimeter. If the fuse is broken, replace it. Such situations are often encountered due to power surges in the power grid. If you do not want to constantly put a new fuse, connect a stabilizer to the equipment. It will reliably protect the system from voltage surges.

The pump may make a loud noise when starting up. This signals that air has entered the closed circuit of the circulating system. They prevent such a phenomenon by installing specials. node in the pipeline. Such a small element eliminates the possibility of air congestion in the system. If a special assembly has not been installed, you will have to purge the pipeline. Severe noise, as well as perceptible vibration, sometimes occur due to wear on the bearing, which is placed on the impeller wheel. Disassemble the housing of the unit, analyze the condition of the bearing, replace it with a new one if necessary.

Circulation pump repair

When the pump does not provide the required pressure of the coolant, the reason lies in the wrong (in the opposite direction) rotation of the impeller. This problem only occurs when pumping equipment is connected to a 380-volt mains supply. The solution is to connect the wire to the correct phase. Also, the head decreases with an increase in the viscosity of the coolant. In situations like this, the wheel encounters high resistance and cannot fulfill its function. You will need to remove the strainer from the pump, clean it or replace it.

As you can see, it is quite possible to repair the circulation pump with your own hands. Of course, when it comes to common breakdowns. In other cases, it is better to entrust the restoration of the pump to the specialists of the service centers.

Proper handling and regular maintenance of pumping equipment eliminates the need for repairs for many years. Consider the following when operating your pump:

Do not start the pump if the piping is not filled with thermal fluid.
Turn on the circulation equipment at least once a month for 15–20 minutes. Prolonged downtime of the pump is guaranteed to lead to malfunctions of its individual components and mechanisms.
Follow the manufacturer's recommended volume of pumped liquid. If the device is designed for 100 liters of coolant per hour, it is forbidden to pump more water through it.
Before the start of the heating season, check the system for leaks, the correct connection of the circulation unit to the mains. Carry out test runs of the pump to ensure that there is no vibration or abnormal noise.

Regular maintenance of the circulating pump is also of great importance for the stable operation of the circulating pump. You can do this procedure yourself. You need to make sure that the wires leading to the terminals are securely fixed, that there are no leaks in the unit, that there is a ground connection between the terminal and the pump body. You also need to lubricate the threaded flanges every 1–3 months and tighten all the pump bolts. Do not forget about the preventive measures described, and then the circulation unit will serve you without accidents for decades. Image - DIY circulation pump repair step-by-step instructions

Circulation pump: DIY repair

This article is devoted to the rules of operation and maintenance of equipment for pumping water used in heating systems.But before you figure out how to repair circulation pumps with your own hands, you need to get an idea of their design features and the principle of operation.
We hope that our instructions will fill the information gap. And the video in this article on the topic: "Do-it-yourself repair: circulation pump" - will help you independently cope with any problem that arose during operation.

First, let's answer the question: "What is a circulation pump?"
Its main task is to provide circulation or recirculation of water through the heating system. In the first case, it moves along a closed loop, and in the second - to different points of supply, and with partial losses.
Despite the fact that circulating pumps move fairly large volumes of liquid, they do not create much pressure. Yes, this is not required of them.
According to the classification, they belong to the category of vane pumps, the most popular of which are: centrifugal, diagonal and axial.
They have a general principle of operation based on the interaction of the pumped liquid with the blades of the working body. But the very mechanism of this effect is different, and therefore their designs and performance are also different.

In these pumps, the impeller is mounted on a shaft and rotates freely inside the chamber. It consists of two parallel disks, and smoothly curved blades connect them together. When the engine is started, the discs begin to rotate in one direction, and the blades in the other.

Household circulation pump, centrifugal type

Water that gets from the suction pipe into the inter-blade channels is forcefully thrown out of the wheel, creating a certain pressure. The liquid is removed through a spiral chamber, and through a diffuser and a branch pipe it is fed into the pipeline. The larger the diameter and speed of rotation of the wheel, the higher the pressure is created.
Centrifugal pumps can have more than one working body, but several, which, accordingly, increases the performance of the mechanism. But since the pressure is not so important in heating systems, a single-stage pump is sufficient for them.

Here is a completely different design of the working body. The wheel consists of a hub, and blades with a rounded edge fixed to it.
The casing of the axial pump is a tubular chamber filled with water, inside which the wheel rotates. The fluid, in this case, moves along the axis of the sleeve, which is why this design got its name.

Axial circulation pump, industrial

Since when moving through the chamber, the fluid flow swirls, before reaching the elbow it enters the guide vanes. Its function is to extinguish the turbulence and direct the jet into the pressure pipeline.
There are two types of axial-flow pumps: the blades on the sleeve can be rotary, or rigidly fixed, which allows you to change their technical characteristics. Compared to pumps of a centrifugal design, axial units have a higher efficiency. According to this principle, mainly industrial equipment is created, and you can see one of these options in the photo above.

A distinctive feature of these pumps is the fact that the fluid flow moves through the chamber not radially, and not along the shaft, but deviating from the pump axis at a certain angle. This feature allows the use of both centrifugal and lifting forces at the same time, so we can safely say that the diagonal pump combines the characteristics of the two previous options.
The diversion of the liquid flow in the diagonal pump can be carried out: both along the volute and through the tubular chamber - it depends on the modification.
In terms of performance, it occupies an intermediate position between centrifugal and axial design. Therefore, both domestic pumps and units for industrial circulation systems can be diagonal.

The circulation pump ensures uniform distribution of the coolant throughout the heating system, and most importantly, prevents the formation of air jams, which lead to a decrease in its temperature.
So:

Usually, two identical pumps are installed in the heating system, which work alternately. That is, one pumps water, and the second is in reserve at this time.
But there is also a more convenient option: a double pump. It is much easier to introduce it into the heating system with your own hands. Such models are offered today by almost all leading manufacturers of this equipment.