Adjusting the pressure switch for a hydraulic accumulator: instructions on setting up equipment + expert advice

To ensure that the water pressure in the autonomous water supply (heating) system remains stable, a special device is installed in it - a hydraulic accumulator. At the same time, an integral part of this unit is a very small device - a pressure switch.

If the latter is not configured correctly, the hydraulic accumulator will constantly turn on and off unnecessarily. As a result, we will get excessive energy consumption and rapid wear of pumping equipment.

Agree, by installing a hydraulic accumulator at home, we want to increase the efficiency of the water supply system and the stability of its operation. However, if the adjustment of the pressure switch is carried out with errors, then the task will not be achieved. It is extremely important to set up this small device accurately and according to the rules. Moreover, it needs to be adjusted both during initial installation and later, during continuous operation.

Operating principle of a pressure switch

An autonomous water supply system in a private house consists of water pipes, a pump and control and cleaning elements. The hydraulic accumulator in it plays the role of a water pressure control device. First, the latter is stored in the battery, and then, as needed, it is consumed when the taps are opened.

This configuration of the water supply reduces operating time pumping station, as well as the number of its “on/off” cycles.

The pressure switch here performs the function of controlling the pump. It monitors the filling level hydraulic accumulator water, so that when this tank is empty, turn on the pumping of liquid from the water intake in time.

The main elements of the relay are two springs for setting pressure parameters, a membrane with a metal insert that responds to water pressure, and a 220 V contact group.

If the water pressure in the system is within the parameters set on the relay, the pump does not work. If the pressure drops below the minimum setting Pstart (Pmin, Rvkl), then electric current is supplied to the pumping station to make it work.

Then, when the hydraulic accumulator is filled to Pstop (Pmax, Poff), the pump is de-energized and turned off.

The relay considered step by step works as follows:

1. There is no water in the accumulator. The pressure is below Pstart - set by a large spring, the membrane in the relay moves and closes the electrical contacts.
2. Water begins to flow into the system. When Pstop is reached, the difference between the upper and lower pressures is set by a small spring, the membrane moves and opens the contacts. As a result, the pump stops working.
3. Someone in the house opens the tap or turns on the washing machine - the pressure in the water supply decreases. Then, at some point, there is too little water in the system, and the pressure again reaches Rstart. And the pump turns on again for pumping.

Without a pressure switch, all these manipulations with turning the pumping station on/off would have to be done manually.

The data sheet on the pressure switch for hydraulic accumulators indicates the factory settings to which the control springs are initially set - almost always these settings have to be changed to more suitable ones

When choosing the pressure switch in question, first of all you should look at:

• maximum temperature of the working environment - for hot water supply and heating there are their own sensors, for cold water supply their own;
• pressure adjustment range - possible settings Pstop and Pstart must correspond to your specific system;
• maximum operating current - pump power should not be higher than this parameter.

Settings the relay in question pressure is made based on calculations taking into account the capacity of the accumulator, the average one-time water consumption by consumers in the house and the maximum possible pressure in the system.

The larger the battery and the greater the difference between Rstop and Rstart, the less often the pump will turn on.

First step before setup

The pressure switch is adjusted during initial installation and then, if certain problems arise in the plumbing system.

In the second case, before you start setting up the relay unit, you need to establish the cause of the problem. Perhaps the problem is not at all with the device in question; there is no need to touch it.

Before setting the relay, you must make sure that the accumulator, pipes and fittings hold pressure. If there are fistulas and leaks in the system, you must first get rid of them

The second extremely important point is water purification. The accumulator and relay have a rubber membrane. If sand gets into the pipes, this rubber will deteriorate (crack) and will no longer hold pressure. IN hydraulic accumulator system Cleaning filters must be present.

If the pressure in the water supply according to the pressure gauge has reached Pstop, but the pump continues to work, then the problem usually lies in clogged pipes and/or filters. It is also possible to have the voltage supply contacts to the pumping station go to the relay.In the first case, you need to get rid of sand and scale in the system, and in the second, check the contact group and 220 V wiring.

It is also possible that the water from the pipes in the house is completely drained, but the pump does not want to turn on. Here, first of all, we check the power supply.

If there is voltage in the network, the wiring and contacts are working properly, then “9 out of 10” the pressure switch has failed. It will have to be replaced with a new one; it is almost impossible to somehow repair this device.

Step-by-step adjustment instructions

Conventional plumbing gaskets are rated at 6 bar, with a maximum and short-term capacity of up to 10 bar. A working pressure in water supply systems and heating of residential buildings in most cases fluctuates between 2–3.5 bar.

You should not set the Rstop relay above 4 bar. Most household models of this device on the market have a maximum Pstop of 5 bar. However, setting this parameter to the maximum of “five” is not recommended.

Do not overtighten or loosen the springs on the device until they stop; this may lead to its incorrect operation. It is necessary to leave a small margin for tension/loosening.

A circuit from the 220 V network passes through the pressure switch of the hydraulic accumulator to power the pump; before you start adjusting the device, it must be de-energized

Large spring - setting the pressure to start the pump. Small spring - setting the pressure difference to turn off the pumping station.

The accumulator relay is configured as follows:

1. Water is drained from the water supply. Then the working pressure in the bulb with air is set in the hydraulic accumulator - 10% less than the planned start-up.
2. The power to the relay is turned on and the pump starts working.The pressure gauge is used to record the pressure when it turns off (Pstop).
3. The faucet in the sink opens a little with a small trickle. The pressure is recorded when the pump is turned on again (Rstart).

To increase the Rstart value, tighten the large spring clockwise. To increase the difference between Rstart and Rstop, tighten the small spring.

These settings are reduced by loosening the springs counterclockwise.

The datasheet on the relay indicates the minimum pressure difference between Рstop and Ррст (usually 0.8 or 1 bar); a small spring cannot be set to lower parameters

After setting the required Rstart and Rstop, the relay with the pump is connected to the network. If everything works as it should according to the pressure gauge, then the setup is complete. Otherwise, the above three steps are repeated again.

Advice from experienced specialists

It is recommended to connect the accumulator pressure switch to the electrical panel of the house via a separate line with its own RCD.

It is also imperative to ground this sensor; for this there are special terminals on it.

It is permissible to tighten the adjusting nuts on the relay as far as possible, but it is not recommended at all. A device with tightly tightened springs will work with large errors in the set Start and Stop, and will soon fail

If water is visible on the body or inside the relay, the device should be immediately disconnected from power. The appearance of moisture is a direct sign of a rupture of the rubber membrane. Such a unit must be immediately replaced; it cannot be repaired or continued to be used.

Cleaning filters must be installed in the system. It’s impossible without them. However, they need to be cleaned regularly.

Also, once every quarter or six months the pressure switch itself should be washed. To do this, unscrew the lid on the device with the inlet pipe at the bottom. Next, the opened cavity and the membrane located there are washed.

The main reason for breakdowns of the hydraulic accumulator relay is the appearance of air, sand or other contaminants in the pipes. The rubber membrane ruptures, and as a result the device must be replaced

The pressure switch should be checked for correct operation and general serviceability once every 3–6 months. At the same time, the air pressure in the accumulator is also checked.

If, during adjustment, sharp jumps in the needle on the pressure gauge occur, then this is a direct sign of a breakdown of the relay, pump or hydraulic accumulator. It is necessary to turn off the entire system and begin a full check of it.

Conclusions and useful video on the topic

How to properly configure the pressure switch:

In simple words about pressure switches for hydraulic storage tanks:

How to adjust the pressure switch in a pumping station:

Without a properly functioning and correctly configured pressure switch, the hydraulic accumulator turns into an unnecessary piece of hardware. Adjustment of the device in question, at first glance, looks extremely simple - only two springs that need to be tightened/loosened. However, setting up this device has its own nuances. If you make mistakes during adjustment, then instead of being useful, the hydraulic accumulator can only bring problems.

If you have personal experience in setting up a pressure switch or have any questions, please write in the comments block below. Our experts will definitely help you understand the selection and configuration of this device to maximize the efficiency of your water supply or heating system.