Function of Thermistors in Aircon Units

Thermistors are tiny heroes in air conditioning units, checking the temperature and keeping rooms cool. They sit near the evaporator coils and send signals to help control how much cold air comes out.

Think of them like secret agents who make sure everything stays perfectly chilly! In aircon units, you’ll find NTC thermistors that adjust well to temperature changes, some with copper tubes for extra control, and others stuck on pipes where the cold stuff flows.

Not all heroes wear capes; some come in small packages like the M14 threaded PTC thermistors handling high pressures in compressors. AC units also have motors that can get very hot without their own kind of thermistors watching over them.

It’s quite a problem when these little gadgets go wrong because fixing or changing one can cost up to $250 not counting what you pay someone to do it. Plus, if they break, your room might not stay as cool as you want.

Aircon printed circuit boards talk to thermistors so they know what’s going on inside. To keep things running smoothly, taking care of your unit’s thermistor is important – replacing it safely takes a professional touch.

This article will share more about why these components matter so much for fresh and comfortable air at home. Now let’s uncover their secrets!

Role of Thermistors in Air Conditioning Units

Transitioning from our overview, let’s delve into the specifics of thermistors in air conditioning units. These temperature sensors play a crucial role in maintaining comfort and efficiency.

Thermistors constantly check the air and evaporator coil temperatures. They send this data to the aircon’s control unit. With this information, the system adjusts cooling power and manages how much it runs.

In an air conditioning unit, you’ll find various NTC thermistors working together. Copper tube NTC thermistors sit close to where cool air comes out. They sense changes quickly. Epoxy air temperature sensors monitor room conditions for HVAC systems.

Clip-on pipe NTC thermistors attach directly onto refrigerant lines, helping to regulate how much coolant moves through the system.

PTC thermistors have a different job inside compressors—especially M14 threaded ones designed for high pressure. They keep an eye on pressure levels to prevent damage from extreme changes.

NTC types also track motor heat, ensuring that parts don’t overheat or wear out too fast.

Remembering that Aircons need accurate temperature readings; thermistors are essential tools for getting it right every time they switch on or off automatically based on what’s needed for comfortable indoor climates.

Differences Between Thermistors and Thermostats

Understanding the distinctions between thermistors and thermostats is fundamental in grasping how air conditioning systems function effectively. Herein lies a comparative overview:

FunctionalityResponds to temperature changes by altering its electrical resistanceRegulates the environment’s temperature by switching heating or cooling devices on or off
ComplexityGenerally more complex, allowing for precise temperature measurementsSimpler devices that control temperature based on preset ranges
ControlFeeds temperature data to a control unit, which adjusts the cooling/heating operationActs as a control unit itself, based on user-defined settings
ComponentsMade of semiconductor materials that are sensitive to temperatureConsists of bi-metallic strips or gas-filled bellows that mechanically operate switches
UsageCommonly used in the feedback systems of electronic climate controlUsed in residential and commercial HVAC systems for rudimentary temperature control
ApplicationEmbedded in circuits for continuous temperature monitoringMounted on walls as a user interface to set desired temperatures

The table above provides a snapshot of the key contrasts. Thermistors offer nuanced temperature sensing, adapting electrical resistance in response to even slight thermal shifts. Thermostats, on the other hand, make binary decisions to maintain a designated temperature range. While thermistors engage in a complex interplay with aircon units’ control systems, thermostats typically involve less intricate interactions. These distinctions play crucial roles in the operation and maintenance of aircon units, impacting performance, efficiency, and user control.

Consequences of a Faulty Thermistor in Aircon Units

Moving from the differences between thermistors and thermostats, it’s crucial to know what happens if a thermistor in your aircon unit stops working properly. A faulty thermistor may cause inaccurate temperature readings.

This means your air conditioner could start acting up. It might not cool the room enough, or it might run non-stop and freeze up.

The air conditioner depends on correct readings to work right. If the thermistor is broken, it can’t sense temperature well. The cooling cycle gets messed up because of this. Your aircon may blow only brief bursts of cold air before stopping too soon or keep going when it shouldn’t.

Expect repair costs for indoor units to be around £90 to £160, while outdoor ones can hit up to £250. Repairing them requires a skilled technician, so factor in their charges as well.

Keep in mind that fixing issues early helps avoid bigger problems later on with evaporator coils and condenser units—all parts of an efficient heating and cooling system that save energy and money over time.

Understanding Aircon Printed Circuit Boards and Thermistors

Aircon printed circuit boards (PCBs) act like the brain of your air conditioner. They control how the unit works by using electrical pathways to send instructions. The PCB relies on information from thermistors to make smart decisions about heating and cooling.

Thermistors are special parts that measure temperature with great accuracy. They sit close to the evaporator coils, where they keep track of how warm or cold the air is.

Think of thermistors as tiny detectives inside your air conditioner. They spot even small changes in temperature and tell the PCB right away. This rapid communication means your aircon can adjust itself quickly, keeping you comfortable without wasting energy.

Handling a PCB requires care because it has lots of delicate wires. If something goes wrong with a thermistor, an expert should check it out to avoid damage to other important parts like copper tubing and conductivity pathways.

Guidelines for Thermistor Maintenance and Replacement

Taking care of thermistors helps keep your aircon unit working well. Regular checks and timely replacements can save you from bigger problems later. Here are some guidelines to help you maintain and replace thermistors:

  • Check the thermistor’s resistance regularly. Use a multimeter to make sure it matches the expected values.
  • Look for signs of wear or damage. If a thermistor looks cracked or worn out, it’s time to replace it.
  • Clean the thermistor gently with a soft brush or cloth. Dust and dirt can affect its accuracy.
  • Make sure the thermistor has good contact with the air or surface it measures. A loose fit can give wrong temperature readings.
  • Replace any faulty thermistors quickly to avoid issues with cooling performance.
  • Use the correct type of thermistor when replacing one; NTC for gradual changes, PTC for sharp responses.
  • Follow manufacturer instructions when installing a new thermistor. This ensures that it will work as expected.


Aircon units need thermistors to keep rooms cool and comfortable. These tiny temperature-sensing champions help your air conditioner work just right. Remember, regular checks on your thermistor go a long way in saving energy and avoiding breakdowns.

If you spot any issues, get them fixed quickly. Your cool summer days depend on this smart little device!


1. What exactly is a thermistor in an aircon unit?

A thermistor is a temperature-sensing device inside air conditioners that measures how hot or cold it is in the room, helping the system decide if it needs to cool down or warm up.

2. How do thermistors work differently from thermostats?

Thermistors react to changes in temperature, while thermostats set and maintain the desired warmth or coolness. Think of a thermostat as a captain giving orders, with the thermistor as the lookout spotting changes in weather conditions.

3. Are there different types of thermistors used in aircon units?

Yes, there are two main types: PTC (Positive Temperature Coefficient) and NTC (Negative Temperature Coefficient). An NTC thermistor reduces its resistance when it gets hotter. A PTC does the opposite; its resistance goes up with heat.

4. Why are NTC thermistors important for energy saving in heating and cooling systems?

NTC thermistors help save energy because they detect very small changes in temperature quickly, making sure your air conditioner doesn’t work harder than it needs to by constantly adjusting itself efficiently.

5. Can you find a thermistor in other devices beyond aircon units?

Absolutely! You’ll also find these clever sensors doing their job in refrigerators and freezers, making sure your food stays at just the right chilly temperature.

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