Water pressure sensor in the water supply system

2024 Author: Aaron Duncan | [email protected]. Last modified: 2023-12-16 03:30

Every owner of a private house always wants his home to be comfortable and cozy. The main amenities are undoubtedly sewage and running water. The optimal solution to the issue of water supply to a private house is the installation of a submersible or deep-well pump or a pumping station. The installation is called an automatic pump because it supplies water to the house and maintains the necessary pressure in the water supply system during its operation.

Such automatic water supply stations are used both in private houses and in summer cottages, as well as in apartments. Their advantage lies in leveling water hammer in the water supply system, and in the event of a power surge or power outage, they themselves store the necessary supply of water, that is, a reserve.

Wherever a pump or pumping station is used, they always have adjustment sensors. They turn the pumps on and off. So,when purchasing such equipment, it is extremely important to choose the right range, at which the pump will work correctly. If this range is too large, then the pump will react too strongly to drops, and then the water pressure sensor in the pipeline will work very often. If the adjustment is too small, the pump will turn on more often, and this will result in its failure.

Usually, pressure switch sensors are configured in the store. But if it turned out that such settings were not made, then everyone can do it on their own without much effort.

The water pressure differential sensor is a responsible device. It must be present in every pumping station, and when installing a pump connected to a well or a well, it is simply necessary. And an equally important role in such a set of equipment belongs to the pressure sensor, since it is he who gives the command to the pump to turn on or off at the right time. Thus, the necessary pressure is maintained in the water supply system.

Only correctly set limits of the highest and lowest water pressure will allow the pump not to overheat and work intermittently, which means that it will last much longer than if it worked constantly or turned off rarely.

Working principle

The water pressure switch sensor is a separate unit, hermetically sealed, in which there are springs that are responsible for the pressure limits. They are adjusted with special nuts using a wrench. Membranetransmits the force of water pressure. It either weakens the spring (at low pressure) or holds its resistance (at high pressure).

This action of the membrane on the spring leads to the connection and opening of the contacts in the pressure switch itself.

When the pressure drops to a minimum, the electrical circuit is automatically closed, the pump motor is energized and turns it on. The pump runs until the pressure reaches its maximum value. After that, the relay will open the circuit itself, and the voltage supply to the pump will stop. As a result, the pump turns off and waits for a new command. During this period, the heated parts of the pump cool down, and it does not overheat.

As a rule, the water pressure sensor for the pump is set in the range from 1 to 7-8 bar. The factory setting is automatically activated at 1.5 bar (this is the minimum - the pump turns on) and 2.9 bar (this is the maximum - the pump turns off).

Pressure adjustment

There is a certain direct relationship between the capacity of the accumulator, the pressure of the water supply and the settings of the pressure sensor. Therefore, before you start setting up the relay, be sure to check the air pressure inside the accumulator.

Important: be sure to disconnect the relay from electricity before setting.

drain water from accumulator;
unscrew the side (or bottom) cover on the accumulator;
using a car tire pump, check the pressure - the norm is about1.4-1.5 atm;
if the value obtained is less, then pump up the pump to the desired level;
if the pressure is higher than normal, then "bleed" the excess by pressing the tip of the nipple.

Instructions for setting up the relay sensor

The pressure switch sensor should be set up under pressure and in a working water supply system. First you need to turn on the pump so that the pressure in the system rises until the water differential pressure sensor trips and the pump turns off.

Adjustment is carried out with two screws that are installed under the cover that closes the relay automation.

To change the limits of the relay sensor operation, you need to

Check and record the existing switch-off and switch-on pressure when the station (or pump) is running. That is, carefully take readings from the pressure gauge.
After that, disconnect the pump from electricity and, having unscrewed the screws, remove the top cover from the relay and loosen the nut holding the small spring. Under it are two screws. The largest screw, which is installed at the top of the device, is responsible for the maximum pressure. It is usually denoted by the letter "R". It won't be difficult to find him. The second, smaller one is located below the large screw, and its designation is "ΔP".
Start setting the minimum pressure. To do this, you need to release or tighten the large spring, which has the designation "P", by turning its screw in the direction of "-" - decrease (counterclockwise) and "+" - increase (clockwise).
Opening the tap, reduce the pressure and wait for the pump to turn on.
Having remembered the readings on the pressure gauge, turn off the power again and continue the adjustment, trying to achieve the optimal indicator.
To adjust the cut-off pressure, loosen or tighten the small spring marked "ΔP" by turning its screw between the "-" and "+" signs, which indicate the difference between the cut-off and turn-on pressures and most often range from 1 up to 1.5 bar.
Turn on the pump, wait for the water pressure sensor to work. If the result does not suit us, then drain the water again and continue the adjustment further.

Features of adjusting the water pressure sensor

When the cut-off pressure increases, "ΔP" increases. By default, the factory settings are as follows: P on=1.6 bar, P off=2.6 bar with Δ=1 bar.

You can set the differential to around 1.5 bar by setting P (off) to 4-5 bar and P (on) to around 2.5-3.5 bar. In this case, the pump will turn on less often, since with an increase in the differential, the water pressure drop in the system will increase. However, cranes may react negatively to water hammer.

water pressure sensors for the water supply system

When adjusting the pressure limits, the capabilities of the pump should also be taken into account. If the value of 3.5-4.5 bar is indicated in the product passport, then the water pressure sensor must be set to 3-4 bar. If you do not leave a "gap", then overload is inevitable, and the pump motor will run constantly, without turning off. So the sensorpressure significantly affects the life of the pump and therefore its condition must be constantly monitored.

If you do not change the factory settings of the sensor, then you should check it at least once a quarter. This will extend the life of the pump and avoid unnecessary financial costs.

Possible system malfunctions

No pump or pumping station should be operated without water. This is the most common cause of their failure, of course, if regular power outages do not occur, which extremely negatively affects not only the operation of the pump, but also disables the water pressure sensor.

Most often, thermoplastic is used in pumps - plastic with increased wear resistance. Its price is low, but the benefits are obvious. However, for the system, water acts as both a lubricant and a coolant. When the equipment is operated without water, the parts heat up quickly and as a result are deformed. This leads to jamming of the motor shaft, and it burns out. In the best case, the pump continues to work, but no longer corresponds to the specified capacity.

Most problematic use cases

Wells and wells with a small amount of water. In this case, it is extremely important to select a pump of the appropriate power and correctly configure the water pressure sensor. This is also important because in the summer, especially on hot days, the water level in underground sources drops noticeably and the pump performance can be much higher than required.
When the pump is on, the water tank shouldconstantly monitored to turn it off in time.
During dry periods, it is extremely important to monitor the pressure in the network water supply system, into which a water pressure sensor is embedded, in order to track the moment when the pressure disappears completely.

Types of equipment and relay protection

Pressure sensor with dry running protection. Such devices provide for opening contacts when the pressure drops below the set limit. The factory settings are usually between 0.4 and 0.6 bar and cannot be changed. This level drops only if there is no water in the system. After the cause has been eliminated, the pump can only be switched on manually. However, water pressure sensors can also be used. Such a model is suitable for a water supply system of this type only if there is a hydraulic accumulator. The use of such a relay loses its meaning without automatic operation of the pump. It can be used with both submersible and surface pumps.
The most inexpensive option is a float switch. It is used in systems for raising water from almost any reservoir. There are also those that can only fill - opening the contacts to stop the pump motor saves from overflow, and those that protect against "dry running". A cable from the float is connected to one phase, and when the water level drops below the level set in the settings, the contacts open and the pump turns off. Therefore, the pump float should be fixed in such a way that water always remains in the tank.
Flow relay with "relaypressure" ("press control"). A compact flow switch can replace a hydraulic accumulator and a water pressure sensor in an apartment. It gives a signal to the pump when the pressure drops to a threshold of 1.5-2.5 bar. If water does not flow through the relay, then the pump turns off. The effect is achieved using a built-in flow sensor, which records the flow of water through the relay. As soon as the pump detects the presence of a "dry run", it will immediately turn off. At the same time, a small delay does not affect its performance in any way.

Relay selection

When buying a relay sensor, you need to carefully consider what kind of environment it is intended for. Check the range of its settings and all additional functions, if any.