20 Tips on Dental Chair Repair and Maintain

Table of Contents

Ⅰ. How a Dental Chair Works

The dental chair is mainly used to examine and treat oral surgery and oral diseases. At present, the most used is the electric dental chair, whose main structure is divided into eight parts.

The base plate of the whole machine is fixed on the ground, and the base plate is connected to the upper part of the dental chair through the bracket. The action of the dental chair is controlled by the control switch on the back of the chair, and its working principle is to manipulate the switch to start the motor operation, driving the transmission mechanism to work so that the corresponding parts of the dental chair move. According to the needs of medical treatment, the dental chair can be manipulated by the switch button to complete the rising, falling, tilting, leaning, and resetting actions.

Ⅱ. Common Failures of Dental Chairs

The following are common failures of the dental chair

  1. The dental chair suction not working
  2. The dental chair’s oral cavity light does not light up
  3. The water heater does not heat or the water temperature is too high
  4. Dental chair solenoid valve failure
  5. Dental chair circuit board failure
  6. Common failures of the program controller
  7. Dental chair water storage bottle failure
  8. Dental handpiece failure
  9. The dental chair scaler not working properly
  10. Dental chair curing light malfunction
  11. Dental spittoon flushing and gargling issues

Ⅲ. Solutions for Dental Chair Malfunction

1. The dental chair suction not working

Step ①:Self-check

  1. Weak suction check water pressure (2-4kg is normal).
  2. Strong suction check air pressure (5.5-6kg is normal).
  3. Check whether the handle switch and the hanger valve are opened normally.
  4. Check whether the drainage pipe is blocked.
  5. Check whether the strong and weak suction filter cups are clogged.
  6. Check whether the strong and weak suction generator is clogged with dirt.

Step ②:Examination
Check whether the pipeline is broken and whether the connection is sealed.

Step ③: Repair

  1. Clean the pipeline sediment, unclog and repair the pipeline, and if necessary, replace the irreparable pipeline.
  2. Hanging rack valve leakage can not open the suction and spit valve, if necessary, replace the valve body that can not be repaired.

Warm tips.
It is recommended to clean the strong and weak suction filter cup once in 1-2 weeks.

2. The dental chair’s oral cavity light does not light up

led dental chair light
Dental Chair Light

Check the cause.

  1. Whether the lamp beads are burned out.
  2. Induction when the internal relay has no response.
  3. Active joints within the wire are not pinched off.
  4. The light line power butt plug is in poor contact.
  5. Whether the fuse on the public line of the light line power supply is damaged.
  6. Check whether the output of the transformer has a voltage.

Repair method.
Replace the same type of lamp beads and control circuit board.
Power off to re-check whether the lamp line connector is in good contact.
Replace the burnt fuse and transformer without output voltage.

Warm tips.
It is recommended to wipe the transparent cover with a soft cloth, do not wipe the internal reflector, if necessary, directly replace the reflector.

3. The water heater does not heat or the water temperature is too high

Dental chair heater

Verification causes.

  1. Two white power cord and two temperature control line is not normal power
  2. Heating rod damage
  3. The main and vice control panel does not give a signal
  4. The treatment board to control the water heater relay is not working properly
  5. Temperature controller out of control or insensitive control resulting in high temperature

Repair method.

  1. measuring with a multimeter and repairing the damaged wiring.
  2. replace the relay, the main and vice control panel, and the temperature control sensor.

Warm tips.
In the cold season, empty the water heater at the end of each day’s work to prevent the water heater from freezing and cracking at night due to low temperatures.

4. Dental chair solenoid valve failure

Verification causes.

  1. The valve spool reset not sealed good drip
  2. The inlet and outlet nozzle connected to the reverse
  3. Solenoid valve without voltage input
  4. Solenoid valve coil damage no magnetic field

Repair method.

  1. clear the spool blockage.
  2. connect the inlet and outlet pipes according to the direction specified by the arrow on the solenoid valve.
  3. Replace the damaged solenoid valve.

5. Dental chair circuit board failure

Verification causes.

  1. The circuit board power supply is not energized
  2. No signal output of the circuit board
  3. Press the main and sub-button board sound but the circuit board does not work
  4. A loose plug on the circuit board leads to poor contact
  5. The circuit board is short-circuited due to moisture

Repair method.

  1. turn off the power, and blow dry the moisture on the circuit board to prevent short circuits.
  2. Check the indicator lights of the circuit board to ensure that 1 power supply 24V and 2 signals are on, and the two lights are normal after power is applied.
  3. Check the plug of the line and connect all the plugs reliably; replace the damaged circuit board.

6. Common failures of the program controller

Verification causes.

  1. The programmable controller is not energized
  2. The programmable controller is powered on after the dental chair does not lift
  3. Foot control programmable controller with sound but does not work
  4. The machine and chair interlock switch do not reset
  5. The limit switch does not reset

Repair method.

  1. Check the 24 V power supply, indicator light 1 will light up after power is applied.
  2. Check the loose plug, insert the plug accordingly and replace the limit switch that does not reset.

Warm tips.
The packaging of the foot switch must be removed after ventilation! Prevent the pressure of the switch after ventilation, so that the dental chair in the interlocked state can not work.

7. Dental chair water storage bottle failure

Check the cause

  1. The 2.2kg pressure-reducing valve is damaged, resulting in high air pressure in the bottle
  2. The water source switch is wrongly dialed resulting in no water in the instrument tray
  3. The water circuit is blocked resulting in poor water delivery
  4. Quality problems lead to poor pressure resistance of the water storage bottle

Warm tips
When ready to use the water storage bottle water, the water source switches to press down, and the total gas switch opens up to ON. use the first water bottle water needs to open the first water bottle gas switch at the same time, similarly, the use of the second water bottle needs to open the second water bottle gas switch.

8. Dental handpiece failure

Check the case

  1. Dental handpiece dripping water
  2. The dental handpiece is not strong enough
  3. No atomization when the dental handpiece is working
  4. Dental handpiece screw and connector leakage

Repair method.

  1. check the total air intake of the dental chair, the air pressure shall reach 6kg.
  2. repair the foot switch is not connected to the pipe.
  3. replace the damaged valve body and clean the water filter.
  4. (The water source changeover switch on the side box is open) adjust the atomized gas knob.
  5. Replace the damaged and deformed handpiece spiral.

If the scaler of the dental chair does not work properly, please check one by one through the following 5 points:

  1. Check the working power supply of the dental scaler.
  2. Check whether the distance between the foot-operated pneumatic valve body is correct
  3. If the cleaning head is not tightened or has been loosened due to long-term use, the cleaning head should be tightened with the wrench provided after shutting down the machine.
  4. Check whether the power adjustment potentiometer is too small. If it is too small, increase it clockwise.
  5. If any knob is loose, tighten it.

There are many reasons why the light curing lamp cannot work. Check through the following 4 points:

  1. Use a multimeter to measure whether the lamp is burned out. If it is burned out, replace it.
  2. Check whether the light-curing lamp feet are oxidized. If so, use a blade to remove the oxides.
  3. Measure whether the power supply of the light curing lamp is normal and whether the voltage output by the motherboard meets the requirements.
  4. Check whether the fuse is burned out.

Common problem:

  1. The water supply for mouthwash cannot be turned off, and the valve cores for flushing and rinsing have foreign objects stuck in them.
  2. The water supply for mouthwash does not come out, the water pipe is twisted and flattened, and the battery valve coil is burned out.
  3. The mouthwash temperature is too high, a temperature relay in the upper cover of the water heater fails, and the thermostat adjusts the temperature too high.
  4. The flushing basin has poor drainage, the pipes are clogged with dirt, and the plastic pipes are crushed.
  5. No water comes out of the basin, the water pipe is twisted and flattened, and the battery valve coil is burned out.

Method of exclusion:

  1. Remove and wash the spittoon filter.
  2. Arrange or replace the new pipe and replace the battery valve with a new one.
  3. Replace with a new water heater and readjust the temperature.
  4. Remove the dirt, remove it, and soak it in hot water to restore it to its original state, or replace it with a new pipe.
  5. Organize or replace new pipes and replace new battery valves

Ⅳ. How to Maintain the Dental Chair

1. Cleaning of the chair surface of the dental chair

PU material seat cushions try to avoid the patient’s keys and other sharp objects scratching. Before use in winter, it is recommended to wipe with warm water and start working.

dental chair cover set
Dental chair cover set

Microfiber leather seat cushions can be directly cleaned with a water wipe and available white wax polishing.

It is recommended to use an extra dental chair cover to protect the cushion of the dental chair. KINSUN Dental can support you with a lot of kinds of dental chair covers.

2. Dental chair light maintain

The light arm is controlled by a tension spring, so try not to pull the light head back and forth under non-working conditions.

3. Dental chair frame part and motor maintenance


  1. The dental motor input voltage is 24V(DC)
  2. The motor force is minimal when the treatment chair is in the highest position
  3. When the angle between the backrest and the cushion is the largest, the motor is under the least force.
  4. Apply lubricant at the motor push rod after one year of use

Warm tips.
Please do not use liquid handpiece oil instead of resin oil for maintenance, otherwise, it will lead to a strange noise when the dental chair is running.

4. Cleaning of dental chair water filter and air pressure reducing valve

Operation steps of maintenance

  1. Rotate the bottom of the water filter counterclockwise to remove the center screen and rinse it with clean water.
  2. Rotate the air filter transparent cup counterclockwise to clean the filter element.
  3. Remove dirt to prevent damage to the parts caused by entering the water pipe and valve body, resulting in the phone not functioning properly or not being effective.

5. Cleaning of the suction filter of the dental chair

Operation steps

  1. Raise the dental chair to the highest position.
  2. Rotate the filter according to the filter arrow, remove the screen, and rinse it with clean water.
  3. Remove the foreign matter to prevent blockage affecting the suction power.
  4. Rinse the strong and weak suction channels with clean water.

6. Cleaning of the dental chair spittoon

Operation steps

  1. Shake the spittoon with slight force from side to side and pull it out, do not rotate it.
  2. After cleaning, put it back in place and flush the pipe by pressing the flush button.
  3. Remove foreign objects from the spittoon to prevent the drainage pipe from being blocked.

7. Turn off the dental chair main switch after use

At the end of each day’s work, turn off the dental chair’s water, gas, and electricity main switch, which can extend the life of the dental chair water and gas circuit 2-3 times.

● Dental Chair Circuit Principle

● The principle of dental chair water and gas

● The principle of dental chair water, gas, and electricity

8. Care and maintenance of dental handpieces

dental high speed handpiece with bearing

Maintenance steps
1. Cleaning
The dental high-speed handpiece in work will have part of the grinding off debris residue in the internal, which will affect the normal speed of the handpiece. After work, use an ultrasonic cleaning machine to clean the handpiece, and then use the oiling machine to oil the handpiece.

2. Lubrication
Dental handpieces work at the speed of 400,000 — 1 million revolutions, lubrication, therefore, becomes very important.
Warm tip: When using dental handpiece cleaner, try not to touch the handpiece tube to avoid hardening of the handpiece tube.

3. Air pressure
The dental chair air intake air pressure at 6 kg, the working air pressure of the handpiece should be between 2-3 Mpa pressure, and the new handpiece break-in phase air pressure should be about 2 Mpa pressure use.

4. Burs and handpiece
Dental handpieces should not be run without a turning pin or test rod installed, the oscillation at high speed will damage the handpiece bearings.

9. Maintenance of dental air compressors

Maintenance steps
1. Power off
After daily work, remember to turn off the power to prevent it from continuing to work.

2. Exhaust
After daily work, turn off the main valve switch after the gas in the air compressor has been exhausted. The machine pipeline has been inflated to accelerate the aging of the gas pipe, and the pressure switch spring elasticity is weakened, which directly affects the working air pressure.

3. Drain water
Pay attention to the drainage water, the air contains moisture, according to the local air humidity, about once a month (once every half a month when the workload is large).
The above is for reference only, please refer to the actual operation.

Ⅴ. Summary

The above is all about how to repair and maintain the dental chair, Hope this article can help you solve some dental chair maintenance problems.

In addition, we also provide a variety of dental chair accessories, if you are looking for dental chair accessories suppliers, please do not hesitate to contact us.

More Post>>

Wechat QR code

Let's have a chat

Request A Quick Quote