Understanding the Operation and Upkeep of Water Softening Systems

As the industrialization process accelerates, water pollution has become increasingly serious while productivity is improved. Water softening and water purifying systems are two common devices for solving water pollution problems.

Figure 1 Understanding the Operation and Upkeep of Water Softening Systems

The maintenance and troubleshooting methods of water equipment are quite complex but crucial. Only by mastering the correct maintenance methods can the role of the softening water equipment be maximized.

1. Principle of Softening Water Equipment

A water softener, also known as a “sodium ion exchanger”, uses a cation resin to soften the raw water. The main purpose is to allow the cation resin to adsorb calcium and magnesium ions in the water (the main components of scale), reduce the hardness of the raw water, and enable intelligent resin regeneration for recycling.

2. Maintenance of Water Softening Equipment

Operation and Maintenance

For boiler softening water equipment and fully automatic water softener, the following maintenance work should be done during operation:

Figure 2 Maintenance of Water Softening Equipment

1. The external part of the electric control device should be equipped with a sealed cover to ensure stable input voltage and current. This is to prevent the equipment from getting damp or flooded, the electric control device from burning out, and salt bridges from forming on the salt valve.

2. Solid granular table salt (iodized or refined salt is strictly prohibited) should be regularly added to the salt tank, and the salt solution in the salt tank must be in an oversaturated state. When adding salt, be careful not to sprinkle solid granular salt into the brine well to prevent blockage of the salt suction pipeline.

Figure 3 Solid granular table salt

Since solid granular table salt contains a certain amount of impurities, a large number of impurities will deposit at the bottom of the salt tank and block the salt valve. Therefore, the impurities at the bottom of the salt tank should be cleaned regularly.

When cleaning, the drain valve at the bottom of the salt tank can be opened, and clean water can be flushed until there are no impurities flowing out. The cleaning cycle of the salt tank should be determined based on the impurity content of the solid granular table salt.

3. Regularly check the air tightness of the injector and the salt suction pipeline to prevent air leakage from affecting the regeneration effect.

4. The water softener should be dismantled once a year. Clean the impurities in the upper and lower cloth water distributor and the quartz sand cushion, and check the resin loss and exchange capacity. Replace the seriously aging resin. For iron-poisoned resin, it can be revived with a hydrochloric acid solution.

3. Maintenance During Shutdown

Before the temporary shutdown, the resin should be fully regenerated and converted into sodium type for wet maintenance.

Figure 4 Maintenance During Shutdown of Water Softening Systems

In summer shutdown (if a softener is used for heating boilers, it is generally shut down for several months in summer), the softener should be rinsed at least once a month to prevent the growth of microorganisms in the exchange tank, which can cause the resin to mold and clump.

If the resin is found to be moldy, it can be sterilized. Generally, soak it in a 1% formaldehyde solution for several hours, and then rinse with water until there is no formaldehyde odor. 

Winter shutdown should take anti-freezing measures to prevent the water content in the resin from freezing and causing the resin to expand, crack, and break.

The resin can be stored in a saltwater solution, and the concentration of the saltwater should be adjusted according to the temperature conditions.

4. Troubleshooting of Boiler Water Softening Equipment

Figure 5 Troubleshooting of Boiler Water Softening Equipment

(1) Softener does not regenerate.


Check if the power supply is normal including:

  • Checking fuses.
  • Plugs, switches, etc.
  • Reset time.
  • Check or replace controllers.
  • Check or replace the motor.

(2) The softener is delivering hard water.


  • Close or repair the bypass valve.
  • Ensure there is solid salt in the brine tank.
  • Replace or clean the injector.
  • Check the brine tank refill time.
  • Ensure the central tube and O-ring are not damaged.
  • Check and repair the valve body or replace it.
  • Correctly set and adjust the regeneration time or cycle water production.
  • Add resin to the appropriate level and identify the cause of resin loss.
  • Reduce the turbidity of the incoming water or remove and clean the flowmeter or replace it.

(3) Not sucking salt.


  • Increase the inlet water pressure.
  • Check the pipeline and eliminate blockages.
  • Clean or replace the injector.
  • Check and repair the valve body or replace it.
  • Check the drainage pipeline.
  • Select the injector and drainage flow limiter according to the instructions.

(4) Excessive or overflowing water in the brine tank.


  • Reset the brine tank refill time.
  • Check for blockages in the injector and salt suction pipeline.
  • Clean the brine valve and pipeline.
  • Close the inlet valve and wait for power to return before opening it again or installing a liquid-level controller.
  • Check and repair the liquid level controller.

(5) Water pressure loss or rust in the pipeline.


  • Clean the softener pipeline.
  • Clean the control valve, add resin cleaner to the resin bed, and increase the regeneration frequency.
  • Check the backwash and brine water process, increase the regeneration frequency, and extend the backwash time.
  • Install iron removal facilities in the system.

(6) Resin is discharged through the drainage pipe.


  • Ventilate the system.
  • Replace the distributor.
  • Check and adjust the appropriate drainage flow rate.

(7) Continuous drainage from the drainage outlet.


  • Check and repair the valve body or replace it.
  • Manually move to the operating position or close the bypass valve, and then open it after the power supply is normal.
  • Control valves such as F63 are in backwash mode, and the water outlet pipeline is connected to the drainage pipeline.

(8) Brine in the water outlet pipe.


  • Clean or repair the injector.
  • Repair the brine valve or remove debris.
  • Increase the duration of the normal wash cycle.

(9) Decrease in the amount of water produced per regeneration cycle.


  • Regenerate according to correct operating requirements.
  • Increase backwash flow rate and time appropriately, clean the resin with resin cleaner, or replace it with new resin.
  • Redesign the appropriate amount of salt to be used.
  • Recalculate and set based on the laboratory results.
  • Manually regenerate temporarily and reset the regeneration cycle.
  • Remove the flow meter and rinse it with water. If it still cannot turn, replace the flow meter.
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