Do-it-yourself pumping station repair: causes, elimination

Constant pressure in the water supply system of a private house is usually created using a pumping station. It is clear that it is better if it works without problems, but breakdowns happen from time to time. To quickly restore the water supply and save on services, you can repair the pumping station with your own hands. Most of the breakdowns can be fixed on their own – you don’t have to do anything super complicated. 

The composition of the pumping station and the purpose of the parts

A pumping station is a collection of separate devices interconnected. To understand how to repair a pumping station, you need to know what it consists of, how each of the parts works. Then troubleshooting is easier. The composition of the pumping station:

• Submersible or surface pump. Pumps water from a well or well, maintains a stable pressure in the system. It is connected to the house with pipes.
• A check valve must be installed on the pipeline. It does not allow water to drain from the pipes back into the well or well when the pump is turned off. It is usually installed at the end of the pipe, lowered into the water.
  

• Hydraulic accumulator or membrane tank. Metal hermetic container, divided into two halves by an elastic membrane. In one, air (an inert gas) is under pressure, in the other, until a certain pressure is created, water is pumped. A hydraulic accumulator is necessary to reduce the number of pump starts and extend its service life. Creates and maintains the required pressure in the system and a small reserve supply of water in case of station inoperability.
• Block of control and management of the pumping station. Usually this is a pressure gauge and pressure switch, installed between the pump and the accumulator. A manometer is a control device that allows you to evaluate the pressure in the system. The pressure switch controls the operation of the pump – it gives commands to turn it on and off. The pump is turned on when the lower pressure threshold in the system is reached (usually 1-1,6 atm), and it is turned off when the upper threshold is reached (for one-story buildings 2,6-3 atm).

Each of the parts is responsible for a certain parameter, but one type of malfunction can be caused by the failure of various devices.

The principle of operation of the pumping station

Now let’s look at how all these devices work. When the system is first started, the pump pumps water into the accumulator until the pressure in it (and in the system) equals the upper threshold set on the pressure switch. While there is no water flow, the pressure is stable, the pump is off.

A faucet was opened somewhere, the water was drained, etc. For a while, water comes from the accumulator. When its quantity decreases so much that the pressure in the accumulator drops below the threshold, the pressure switch is activated and turns on the pump, which pumps water again. It turns off again, the pressure switch, when the upper threshold is reached – the shutdown threshold.

If there is a constant flow of water (a bath is taken, watering the garden / vegetable garden is turned on), the pump works for a long time: until the required pressure is created in the accumulator. This happens periodically even when all taps are open, since the pump supplies less water than flows out of all points of analysis. After the flow has stopped, the station works for some time, creating the required reserve in the gyroaccumulator, then it turns off and on after the water flow appears again.

Problems and malfunctions of pumping stations and their correction

All pumping stations consist of the same parts and their breakdowns are mostly typical. It makes no difference whether the equipment is Grundfos, Jumbo, Alco or any other company. Diseases and their treatment are the same. The difference is how often these malfunctions occur, but their list and causes are usually identical.

The pumping station does not turn off (does not gain pressure)

Sometimes you notice that the pump has been running for a long time and will not turn off in any way. If you look at the pressure gauge, you can see that the pumping station is not gaining pressure. In this case, the repair of the pumping station is a lengthy business – you will have to sort out a large number of reasons:

• In a well or well no water. If this is true, this situation is called “dry running” and threatens that the motor will burn out. The water that the pump pumps is used to cool the motor. There is no water, it overheats and burns out. To protect against such a situation, special protection is needed: water level sensors (float and electric).
• Large suction line resistance (large length with small pipe diameter) or air leakage (leaky connection).
  • To eliminate highway influence, lower the suction pipe into the drum next to the pump. If the pressure rises normally, the route is to blame and you either need to seal it at the joints, or lay thicker pipes or straighten the existing one (fewer elbows and joints).
  • That check the tightness suction line, after turning off the station, watch the pressure gauge for a while. If the pressure drops when the taps are closed, there is a leak in the system. If not, the system is sealed.
    

• Filter clogged on a pipe or check valve. They are taken out, cleaned, checked for operability, lowered into place and a test run is carried out.
• Another possible reason that the pump does not turn off is a malfunction of the pressure switch or an incorrectly set pump shutdown limit:
  • The pressure limit at which the pump should turn off is too high, the pump is simply not able to build up the required pressure. Then we spend pressure switch adjustment (reduce the trip limit).
  • Check relay contacts – clean them from scale (dark plaque) with sandpaper with a very fine grain (you can use a nail file).
  • Troubleshoot the pressure switch by cleaning it (remove salt from adjustment springs and clean the inlet and outlet). Just be careful not to damage the inlet membrane. If this does not help, a replacement is required.

If the shutdown limit of the pressure switch is much lower than the maximum pressure that the pump can create, and for some time it worked normally, but then it stopped, the reason is different. Possibly the pump the impeller worked. Immediately after the purchase, he coped, but during the operation the impeller was worn out and “now there is not enough strength.” Repair of the pumping station in this case is the replacement of the pump impeller or the purchase of a new unit.

Another possible reason is low voltage in the network. Maybe the pump is still working at this voltage, but the pressure switch is no longer working. The solution is a voltage stabilizer. These are the main reasons that the pumping station does not turn off and does not build up pressure. There are quite a few of them, so the repair of the pumping station may be delayed.

Repair of the pumping station: often included

Frequent switching on of the pump and short periods of its operation lead to rapid wear of the equipment, which is very undesirable. Therefore, the repair of the pumping station should be carried out immediately after the discovery of the “symptom”. This situation occurs for the following reasons:

• Hydraulic accumulator too small. When choosing a pumping station for a house and a summer residence, they often take a small volume hydraulic accumulator – 24 liters or 32 liters. This is very small, since the supply of water in such tanks is only 30-50% of its total volume, that is, only 24-7 liters of water can be pumped into a 12-liter tank. Naturally, such a volume of water is consumed very quickly, which is why the pump turns on often. The method of treatment is the installation of an additional hydraulic accumulator (it is connected in parallel to the already installed one).
• Incorrectly set limits for the pressure switch. To avoid this situation, you can increase the delta (the difference between the pressure to turn off and turn on the pump) and, due to this, lower the threshold for turning on the pump (optimally – 1-1,5 atm). One important point: the pressure at which the pump turns on must be 0,2 atm lower than the pressure in the accumulator. The pumping station can often turn on just because the pressure in the accumulator is lower than the set threshold for turning on the pump. Because:
  • Checking the pressure in the accumulator. To do this, remove the plastic cover, under it is a nipple (like a bicycle one). We connect the pressure gauge, check the pressure. It is usually in the range of 1-1,5 atm. We bleed or inflate (with a bicycle or car pump screwed to the same nipple) so that it is normal.
  • Adjust the pressure switch. Having picked up the parameters, you should get a normally working system.
    

• Clogged check valve. If the valve does not shut off the water, it leaves the system, the pressure drops, the pump turns on. The frequency of switching on is about 10-20 minutes. Exit – check and clean the check valve, replace if necessary.
• Also, the reason may be damage to the accumulator membrane. At the same time, in addition to the frequent switching on of the pump, water is also supplied in jerks: when the station is running with high pressure, when it is turned off, the pressure immediately drops. In this case, there are two options − the membrane itself or the fold has become thinwhich attaches it to the body. In both cases, you will have to disconnect the accumulator and change the faulty part.
• Her one reason for the frequent operation of the pump and the water supply in irregularities is a broken spool at the top of the accumulator. To replace it, you will have to remove the accumulator, remove the membrane and replace the nipple.

Now you know why the pumping station often turns on and what to do about it. By the way, there is another possible reason – pipeline leakage or some connection, so if all of the above does not apply to your case, check if the joint is leaking somewhere.

Air in water

There is always a small amount of air in the water, but when the faucet starts to “spit”, something is not working properly. There can also be several reasons:

• The mirror of water descended and the pump draws water in half with air. The solution in this case is simple – lower the nozzle or the pump itself below.
• The pipeline has become leaky and air enters through one or more connections. Elimination – check connections and restore tightness.
  

The pump station does not turn on

The first thing to check is voltage. Pumps are very demanding on voltage, they simply do not work at low voltage. If everything is fine with the voltage, things are worse – most likely the motor is faulty. In this case, the station is carried to a service center or a new pump is installed.

Other reasons include a plug / socket malfunction, a frayed cord, burnt / oxidized contacts at the point where the electrical cable is attached to the motor. This is something you can check and fix yourself. A more serious repair of the electrical part of the pumping station is carried out by specialists.

The motor hums but does not pump water (the impeller does not rotate)

This error may be caused low voltage in the network. Check it, if everything is normal, move on. You need to check if it’s burned out. capacitor in terminal block. We take a tester, check, change if necessary. If this is not the reason, go to the mechanical part.

First you should check if there is water in the well or well. Next, check the filter and check valve. Maybe they are clogged or defective. Clean, check the performance, lower the pipeline into place, start the pumping station again.

If that doesn’t help, the impeller may be jammed. Then try manually turning the shaft. Sometimes, after a long period of inactivity, it “sticks” – it becomes overgrown with salts and cannot move itself. If you cannot move the blades by hand, the impeller may have jammed. Then we continue the repair of the pumping station by removing the protective cover and unlocking the impeller.

Some types of repair work

Some do-it-yourself pumping station repair steps are intuitive. For example, it is not difficult to clean a check valve or filter, but it can be difficult to replace a membrane or a pear in a hydraulic accumulator without preparation.

Replacing the “pear” of the accumulator

The first sign that the membrane is damaged is the frequent and short-term switching on of the pumping station, and the water is supplied in fits and starts: sometimes strong pressure, sometimes weak. To make sure that the diaphragm is the problem, remove the plug on the nipple. If not air comes out of it, but water, then the membrane has torn.

To start repairing the accumulator, disconnect the system from the power supply, relieve pressure – open the taps and wait for the water to drain. After that, it can be turned off.

Further, the procedure is as follows:

• Loosen the flange at the bottom of the tank. We are waiting for the water to drain.
• We unscrew all the bolts, remove the flange.
• If the tank is from 100 liters or more, unscrew the membrane holder nut at the top of the tank.
• We take out the membrane through the hole in the bottom of the container.
• We wash the tank – it usually has a lot of rusty sediment.
• The new membrane must be exactly the same as the damaged one. We insert a fitting into it, with which the upper part is attached to the body (we twist it).
• We install the membrane in the accumulator tank.
• If there is, install the membrane holder nut at the top. With a large tank size, you can’t reach it with your hand. You can tie the holder to the rope and so install the part in place by screwing the nut.
• We tighten the neck and press it with a flange, install the bolts, successively twisting them several turns.
• We connect to the system and check the work.

Replacement of the pumping station membrane is completed. It’s a simple matter, but you need to know the nuances.