Do-it-yourself pump station repair grundfos

Equipment Grundfos (Grundfos) due to their reliability, performance and ease of use are widely used in all industries.

They are used in the field of housing and communal services in the construction of centralized heating lines, water supply, sewage disposal, servicing agricultural and forestry enterprises, as well as in equipping industrial complexes.

Timely maintenance of a pump or pumping station for any purpose is a guarantee of its correct operation and the durability of the system as a whole. Repairing pumps in a specialized service center, for example, in Sergiev Posad, is initially an expensive pleasure. However, if you are familiar with the device of the unit and understand the principles of its operation, it is quite possible to eliminate the malfunctions on your own.
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The Grundfos range is represented by all major categories of pumping equipment:

• downhole;
• sewer;
• centrifugal;
• circulating;
• multi-stage self-priming units.

Range of pumping equipment Grundfos

Borehole pumps are used in the water supply system and in the arrangement of wells with artesian water, for filling tanks and other water distribution systems. As a rule, these are downhole installations operating in continuous or short-term mode, regulated by a pressure switch and a hydraulic tank. The product package includes three main elements - the engine, the built-in filter and the upper or lower water intake system. Products are represented by the series of equipment SP, SQ and SQE.

Video (click to play).

Let us consider the device of Sololift sewage pumps, using the example of a typical Sololift 2 WC 3 unit. The unit consists of a tank equipped with inlet / outlet openings, into which waste water enters. After the pre-cleaning provided by the filtration system and upon reaching a certain level, which is monitored by the Grundfos level sensor, the pump switches on automatically. Thus, the process of pumping out liquid into a centralized line, septic tank or other disposal tank is started. The unit is also equipped with a shredder that recycles large household waste and prevents clogging of sewer pipes. The simplest installation is capable of raising water to a height of 5-7 m and transporting it 100 m in a horizontal plane.

Monoblock centrifugal pumps of the NB series are distinguished by a one-way suction system and are used in water supply, heating, ventilation, air conditioning and irrigation systems. The torque from the engine is transmitted to the rotor impeller, and fluid enters the central part of the unit. As the blades rotate, water or another carrier of thermal energy, in the case of a heating system, is thrown towards the outer elements of the housing and redirected to the outlet pipe under the influence of centrifugal force. The pressure readings inside the system are regulated by a Grundfos level sensor.

Circulation pumps presented by the series of equipment UP, UPS, UPSD, Alpha 2 are equipped with a wet rotor and are intended mainly for completing a closed-loop heating system. Its operation is based on the centrifugal force generated by the impeller placed on the shaft.When water enters the central part of the rotating wheel from the suction pipe, it is thrown into the peripheral sections of the unit. The advantage of the equipment of this series is the automatic cooling of the rotor, which rotates directly in the pumped medium. Repair of a circular heating pump with a wet rotor is still recommended to be entrusted to professionals.

In the segment of self-priming equipment, the leader is Grundfos MQ 3-35, used in a pumping station with a diaphragm expansion tank. The circulation of water is stimulated by an increase in pressure due to the centrifugal force arising from the rotation of the impeller. When it is displaced from the peripheral compartments of the unit into the pressure pipeline, the pressure in the central part of the impeller decreases and the liquid enters the pump casing. Such models are used to increase pressure and as part of pure water supply systems (drinking or technical).

Circulation pump device Grundfos

As a rule, pump breakdown occurs suddenly and is mainly caused by incorrect operation, which also needs to be given a little attention. Installation of Sololifts, for example, and similar high-performance equipment and the first start-up should preferably be entrusted to specialists.

Before connecting a submersible or surface pump to the power grid or to a hydraulic accumulator, it is necessary to check whether there is liquid in the area of ​​the intake device and in all pipelines of the system - with a "dry" start, the pumping station will fail with almost 100% guarantee. The volume and temperature of the water to be pumped must comply with the performance specifications and the manufacturer's recommendations.

When the pump is idle for a long time, for example, when used in a country house or in a non-residential country house, once a month it must be turned on for 15-30 minutes to prevent oxidation of moving parts.

Despite the differences in design and principle of operation, most types of pumps are characterized by the following types of problems:

• lack of torque;
• premature spontaneous stop of work;
• increased noise level;
• increased vibration;
• insufficient pressure;
• stop after the start.

The lack of torque, despite the fact that the unit is humming, indicates shaft oxidation as a result of prolonged downtime of the equipment or contamination of the system with foreign insoluble or coarse-grained elements in the composition of the pumped liquid. In both cases, cleaning can eliminate the malfunction; less often, measurement of the rotor shaft or the entire engine is required. If the pump does not rotate and does not make noise when switched on, it is necessary to check the parameters of the power supply and voltage.

When the pump shuts down arbitrarily shortly after starting, the problem is most likely caused by excess lime and salt mass in the space between the rotor and the starter. The problem is also solved by cleaning, which requires prior shutdown of the system and dismantling the engine.

A high noise level when switched on indicates the presence of an excess amount of air in the pipelines, which is sufficient to release with a simultaneous increase in the inlet pressure. Sololift repair is not required in this case.

The increased vibration level is due to the fact that the bearing, which the pump is equipped with in some models, has become unusable and needs to be replaced.

Pressure defects occur when the viscosity of the pumped liquid is higher than the capacity of the pumping station, which is eliminated by replacing the clogged filter. Another reason is an incorrectly implemented three-phase connection. This is also the reason for the shutdown of the equipment almost immediately after its start-up.

The device of the pumping station Grundfos

The causes of breakdowns also include uncontrollable external factors - freezing of liquid in pipelines in the event of insufficient insulation or abnormal climatic phenomena and water hammer during a "dry" start.
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Repair of a Sololift pump, as well as repair of a Grundfos pumping station for any purpose, can be done independently, having previously identified the source of the problem.

Equipment diagnostics involves several stages:

• start the pumping station, evaluate the level of noise and vibration;
• check the pressure indicators;
• make sure that the motor does not overheat during operation;
• check the presence and quality of lubrication of the nodal joints;
• make sure the integrity of the structure and the absence of leaks;
• inspect the box to ensure that the terminals are securely seated.

If you are confident that the malfunctions are not caused by lime deposits and contamination, overloading or operating at maximum capacity, the pump can be disassembled. When planning to repair the Grundfos pump with your own hands, make sure that the water is drained from the pipelines and turn off the system. Disassembly begins with the junction box and a visual assessment of the components. As a rule, such an inspection makes it possible to immediately detect a burned out or worn out part. If not, we will continue to disassemble the installation.

The engine must be in an upright position during disassembly.... This will prevent the risk of oil leakage. To diagnose the trigger, an ohmmeter must be connected to the engine. This tool, when the handle is rotated, generates a voltage in the range of 200-300 V, sufficient to take readings on a resistance tester. Too high diagnostic data reaching infinity indicates an interruption of the operating phase, too low - an interturn short circuit. Self-adjustment of the operating parameters with such deviations is impossible.
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Grundfos pumps are most often used to optimize the circulation of the water supply during the heating season or in closed autonomous heating systems. They help to distribute heat evenly in the room and thus make more efficient use of energy.

Grundfos pump device.

These pumps are resistant to voltage surges and have overload protection. They are produced by a Danish company, which provides a guarantee for their quality and guarantees sufficiently high performance. These pumps can be used both at home and in industrial buildings.

However, if this equipment breaks down, the heating system will stop functioning and will remain cold until repairs are carried out.

The most common cause of pump malfunction is the formation of deposits that settle on the walls and, as a result, prevent the machine from starting. This violation can be corrected by doing the repair yourself. If you decide to purchase new equipment, it will be helpful to fix the old one. This way you can use it as a fallback.

For repairs you will need tools such as:

• screwdriver;
• scraper (made of wood);
• hex wrench;
• circle and polishing paste.

The first step is to remove all excess deposits from the shaft and rotor.

Since the main cause of pump failure is dirt build-up, the purpose of repairs is usually to clean the machine. To do this, you need to remove all unnecessary deposits from the two component parts - the shaft and the rotor. This can be done by first unscrewing the pump screws with a hex wrench and thereby disassembling the threaded connection that holds the motor and pump. Once you open it, determine how much rust has collected in it.

Depending on this, it can be removed with a cloth or scraper.In order to disassemble the washer, as well as the rotor with its impeller, it is enough to insert a thin screwdriver into the slots that are located around the support washer. You can determine for yourself how high the likelihood of new deposits forming on a given surface is. If it is smooth, there is much less chance of deposits forming. Now it can be processed with a grinding wheel.

After that, you need to inspect the stator. As a result of work, it can oxidize quite strongly, and in this case it can only be cleaned with a hammer.

For normal operation of the pump, it is necessary to polish its inner walls.

Special attention should be paid to the sensor. The dirt and rust that builds up on it over time often causes Grundfos pumps to lose their performance. As a result, their work may stop altogether. Therefore, the sensor must also be removed and cleaned of deposits. To do this, remove the cover from the control unit and disassemble the pump housing in two halves.

To remove the sensor itself, you must unscrew the screws using the wrench that comes with the pump. After loosening the screws, the sensor housing can be easily removed by hand. If this cannot be done due to settled dirt, you can pry it off with a screwdriver. Since this part is made of plastic, the manufacturer himself recommends cleaning it more carefully and using less aggressive materials. To do this, you can use a regular toothbrush.

In order for Grundfos to work again in normal mode, it is necessary to polish its inner walls. At the same time, the work can be facilitated if you use polishing tools, having previously fixed them in the drill chuck.

If a bearing is stuck in the pump, then it is necessary to disassemble it and try to turn the impeller.

In order to remove lime deposits, the system is filled with a solution of acetic acid and water, which are mixed in equal parts. Threaded connections can be sealed. This will help prevent pump leaks in the future. You can even use a bicycle tube pad for these purposes.

Sometimes the reasons for the pump stopping can be a jammed bearing, the lack of a water flow sensor, or a drop in pressure. To do this, it is not at all necessary to completely disassemble the pump in order to eliminate one of the above problems.

Try to simply switch the equipment to manual mode by removing the switch located on the junction box from the stopper and placing the handle in the middle position. This will allow the pump to run even when the tap is closed. But if this did not help him turn on, then it is necessary to disassemble the pump and try to turn the impeller. If it does not scroll, the pump cannot be repaired.

If the pump works only in manual mode, the cause of the breakdown is the flowing water sensor.

The breakdown can be eliminated by replacing the sensor itself. Sometimes the pump stops working after turning off the water due to the fact that air accumulates in it. In this case, you can lower it by turning the central screw.