To find out which is stronger - water hose, pipes or pump, you can assemble a water supply system without a pressure switch. In all other cases, when supplying water to a house, a device is built into the system that replaces manually turning on and off the supply voltage of the deep-well pump.
It is impossible to imagine individual water supply at home without a relay that allows you to automatically turn off the pump as the water supply system fills with water and turn it on after the water is consumed.
Fig.1 Design pressure switchStructurally, a standard pressure switch for controlling a pump looks like this. The plastic case contains terminal blocks for connecting the power cable and a mechanical device control system with adjustable spring struts; a 4-inch diameter pipe is located outside for connection to the water main. The power cable enters and leaves the pressure switch through two wide inlets; the wires are clamped using a nut with a plastic ferrule.
In the normal state, the contacts are normally closed and the connected device powers the pump motor. When the pressure in the system increases, water acts on a rubber membrane with a piston installed at the inlet of the water pipe of the device. In turn, the membrane piston presses on a movable metal platform, hinged inside the device body at one point. The platform plate rises and opens the electrical contacts; when the pressure decreases, it returns to its original state, closing the contacts.
A screw with a spring and a nut is installed in the center of the device, which sets the distance of the contact plate to the membrane piston - if it is smaller, the device operates at lower pressure, an increased distance will require greater movement of the piston with the membrane to act on the contact pad, which is equivalent to increasing the pressure in the system.
At some distance from the main adjusting screw there is a second adjusting screw with a smaller spring. It sets the range of movement of the contact metal pad, establishing the difference between the pressure that turns the contacts on and off. Thus, the large adjusting screw sets the lower response threshold of the device (the pressure for turning it on), the small one regulates the range of operation of the device for shutdown (adjustment depth).
Rice. 2 Connection diagram Relay adjustment
When purchased, the relay is configured for a specific switching mode, standard values are 1.4 and 2.8 atm, that is, at 2.8 atm. the pump will be turned off and turned on if the pressure is less than 1.4 atm. Usually, when installing a device into a system, you need to select a response threshold - for this you need to know what pressure the pump in the well provides.
If the pressure of the well pump is 2 atm, and the standard value of 2.8 atm remains in the relay, then the pump will never turn off (it physically cannot create a pressure that reaches the response threshold) and after intensive work will go to eternal rest. A less tragic situation is when the pump can produce a pressure of 5 atm, and the relay turns it off at 2.8 atm. In this case, the system does not work efficiently and it is advisable to install a device that matches the pressure of the well water pump.
To take measurements when adjusting the relay, you need a pressure gauge; the work consists of the following steps.
- Water begins to be drained from the system, and the pump activation pressure is recorded on the pressure gauge.
- Close the valves and record the pressure gauge readings at which the pump turns off.
- Adjust the device with a large screw, periodically turning the water on and off until you get desired value lower pressure.
- Then they move on to adjusting the range that sets upper pressure, small screw. The water is also periodically turned on and off until the required value is obtained.
Connecting the pressure switch to the water supply system
When installing a relay in a water intake system, the following rules must be observed.
Rice. 3 Connection diagram of a submersible pump to a hydraulic accumulator - The hydraulic accumulator for water supply systems and the point of connection of the device to the water supply are located nearby - this will avoid switching the pump during sudden short-term pressure surges.
- When installing, please take into account temperature regime— some models operate only in warm conditions.
- To simplify installation, modern surface-type pumps are equipped with a fitting to which a relay and pressure gauge can be directly connected.
Connecting the pressure switch to submersible pump can be done in two ways:
- The device is connected to water pipes through a tee using an adapter fitting.
- Before connecting the hydraulic accumulator to the submersible pump, a five-pin fitting is connected to it, the connected devices (hydraulic accumulator, pressure gauge, relay) and the water main are connected at one point.
Review of popular models
There are two types of pressure switches: mechanical and electronic, the latter are much more expensive and are rarely used. The market offers a wide range of devices from domestic and foreign manufacturers, making it easier to select the required model.
RDM-5 Gilex (15 USD) is the most popular high-quality model from a domestic manufacturer.
Fig.4 RDM-5 Characteristics
- range: 1.0 - 4.6 atm.;
- minimum difference: 1 atm.;
- operating current: maximum 10 A;
- protection class: IP 44;
- factory settings: 1.4 atm. and 2.8 atm.
Genebre 3781 1/4″ (10 c.u.) — budget model Spanish made.
Rice. 5 Genebre 3781 1/4″ Characteristics
- body material: plastic;
- pressure: upper 10 atm;
- connection: threaded 1.4 inches;
- weight: 0.4 kg.
Italtecnica PM/5-3W (13 cu) is an inexpensive device from an Italian manufacturer with a built-in pressure gauge.
Rice. 6 Italtecnica PM/5-3W Characteristics
- maximum current: 12A;
- operating pressure: maximum 5 atm.;
- lower: adjustment range 1 - 2.5 atm.;
- upper: range 1.8 - 4.5 atm.
Pressure switch - essential element in the water intake system, providing automatic individual water supply to the house. It is located next to the hydraulic accumulator, the operating mode is set using adjusting screws inside the housing.
Pressure switch PM/5-3W is made in Italy. Used to create automatic water supply systems both in the private sector and small industrial production. Has excellent performance characteristics and a number of innovations that make it possible to successfully use this device to control water pressure in the system.
Peculiarities
- Applicable for single-phase pumps.
- Long term services
- Durable plastic housing
- Availability of built-in pressure gauge
- The presence of three 1-inch leads allows you to connect a pump, a hydraulic accumulator and a water outlet line.
Specifications
- Mains voltage – 230 V, 50 Hz.
- Maximum power – 1500 W.
- The maximum switching current is 12A.
- Maximum operating pressure – 5 bar.
- The switching pressure control range is 1 - 2.5 bar.
- The shutdown pressure control range is 1.8 - 4.5 bar.
- Hydraulic connection – 1” female x 1” male x 1” male.
Connection diagram
This pressure switch is in great demand due to its High Quality and a successful design - the ability to connect three fittings and the presence of a pressure gauge. Maximum effect operation of the device is achieved in the presence of a hydraulic accumulator. Which allows you to avoid sudden changes in pressure.
We recommend using it to create automatic system water supply to your home or cottage.
How to buy a pressure switch PM/5-3W
You can buy a pressure switch by making a purchase directly on the online store website, or by calling the phone in the Contacts section. Our manager will contact you and arrange delivery or reserve the goods for pickup.
If you need a pressure switch in Moscow, delivery throughout the city and the nearest Moscow region is at your service. For buyers from other regions of Russia - delivery by any transport company or postal service by agreement.
Payment for goods is carried out in the following ways:
1.Payment in cash.
When picking up from the store, or when receiving the goods to the courier.
2.Bank transfer - payment according to the invoice issued for payment as for legal, and for physical persons
When placing an order, select the payment method: "Bank transfer".
After confirming the order, our specialist will contact you and after agreeing on all organizational issues, you will be sent an invoice e-mail which you can pay at any bank or via an Internet client.
1.Pickup.
Pickup times and times:
PVZ m. Sokol: you can pick up your order the next day after ordering from 10 to 18 on weekdays. The order is stored at the point of issue for 3 working days.
Pickup cost:free when ordering over RUB 1,000. (for orders less than 1,000 rubles, the cost of pickup is 80 rubles.)
Attention! Only pre-reserved items are available at the order pick-up point!
The employee at the delivery point does not give any advice on goods!
Directions to the pick-up point are located on the page CONTACTS
2. Delivery in Moscow within the Moscow Ring Road
The following items are delivered free of charge:
Kerosene heaters trademark"Sengoku"
Cost of delivery:
If your order weighs more than 20 kg, the manager will calculate and inform you of the additional delivery cost!
Delivery time:
Delivery is carried out on weekdays from 10:00 to 20:00.
Behind 30-90 minutes the courier calls you and agrees exact time arrival.
Exact delivery address (city, street, house number, apartment or office number, intercom code)
The contact person
Contact phone numbers
3. Delivery beyond the Moscow Ring Road and further within the Moscow region
Cost of delivery:
If the product card does not indicate WEIGHT, you can check it with the manager.
If your order weighs more than 20 kg, the manager will calculate and inform you of the additional delivery cost!
Delivery time:
Delivery is carried out within 1-3 working days from 10:00 to 20:00 without reference to half a day.
Behind 1-2 hours before delivery, the courier calls you and agrees on the exact time of arrival.
What is important to indicate when ordering:
Exact delivery address ( city, district, locality, street, house number, apartment or office number, intercom code)
The contact person
Contact phone numbers
4. Delivery to regions of the Russian Federation
We can send you goods from any of the companies listed below.
SDEK - www.cdek.ru
First Expedition Company (PEC) - www.pecom.ru
The estimated cost of delivery of goods can be found on the websites of these companies or contact our specialist.
What is important to indicate when ordering:
Passport series and number, date of issue
Full Name
Receipt city
If none of the above methods suits you, we will send the goods to your address in another way - as agreed with you.
Good day. Let's look at the diagram for connecting a mechanical pressure switch PM /5 to the network and the pump. Let's look at the diagram first.
When you unscrew the top cover, you will see the following. First, a large screw with a spring for . It is indicated by a capital "P". Second, this is a small screw with a spring to adjust the difference in this parameter in the on and off mode. It is called "delta P". Next there are two terminals for connecting the electrical wire, called the word “motor”. Two – “line”. At the bottom there are two for grounding connections. This is what PM/5 looks like inside. The pressure switch is sold inexpensively in this Chinese store.
Connecting the pump to the network
How do we connect the pump to the pressure switch and the electrical network? Three wires come out of it different color. Blue is a zero worker or simply “zero”. Brown – “phase”. Yellow-green – zero protective or simply “Earth”.
Now let's see how they will “enter” the relay and how to “exit” it. We insert all three wires through a special hole in the housing. Let's connect. Brown and blue in terminals labeled “motor”. Yellow-green to ground. Then we connect the same wires to the power plug. Brown and blue, respectively, from the “line” terminals (network). Yellow-green from grounding. All is ready. The pressure switch PM/5 is connected to the pump and to the network.
