How to Look Up Thermostat Parts

How to Look Up Thermostat Parts

, by Thrive Agency, 6 min reading time

thermostat parts


When you start having temperature issues at home, the problem often lies with your home’s heating, ventilation, and air conditioning (HVAC) system. However, in some cases, the source of the issue isn’t your HVAC system but could be the thermostat.


Problems with your thermostat can arise when there are issues with its internal mechanism. This entails knowing the different thermostat parts to get to the heart of the issue and secure a thermostat replacement for these parts, if necessary.


In this blog, we delve into the different parts of a thermostat, their functions, and signs to look out for that indicate thermostat problems to determine a malfunction in your thermostat. Then, we share tips on how to find thermostat replacement parts online.


Thermostat Parts and Their Functions


Thermostats are typically made up of two basic parts: a base and a cover. Sometimes, a third part, the subbase, can be added for additional functionality. Learn their functions below.




The cover is the external portion of the thermostat. It acts as a barrier that protects the base from external contaminants like dust, lint, hair, and other small debris. It also contains essential control elements such as temperature-setting, system-switching levers, and temperature indicators.




The base comprises the main mechanism that provides all the functionalities of the thermostat. It contains all the different elements and wirings that control the mechanism of the thermostat. Naturally, the components will differ depending on the type of thermostat. As an example, the following are components found in a mercury thermostat:


  • Adjustable Heat Anticipator: Supplies a small amount of heat to the sensing bulb to prevent the system from heating up until the system calls for heat to prevent the system from going over the set temperature.
  • Cooling Anticipator: Similarly, it supplies a small amount of heat when the system doesn’t call for cooling to prevent the system from overshooting the target temperature.
  • Mercury Switch: Provides the switching mechanism that completes the circuit and provides power to the base.
  • Setting Lever: Adjusts heating and cooling anticipators and controls the length and frequency of each cycle.
  • Bimetallic Strip: Converts temperature changes into mechanical displacement, allowing the temperature settings to be controlled.
  • Cool-Off-Heat System Switch: The switch that controls the heating and cooling function of the HVAC system.
  • Fan Switch: The switch controls the air intensity that comes out of the blowers.


Signs Your Thermostat Needs Replacement Parts


Here are some signs to look out for to diagnose issues with your thermostat:


No Power


Having power issues is one of the telltale signs your thermostat has problems. This lack of power can stem from several issues, which include:


  • Dead Batteries: Modern thermostats will have a low battery status on the screen. For non-display thermometers, no such indicators are present. However, in both cases, consider replacing your batteries. It has no power to eliminate the problem as a potential issue.
  • Loose Wiring: Lack of power to the thermostat could be caused by problems with wires that deliver electricity to the base.
  • Blown Fuse: If your circuit breaker has been tripped, call a professional electrician or technician to perform an inspection.
  • Wear and Tear: It’s not uncommon for thermostats to wear out within 10 years or less. If you’ve had your thermostat for over 10 years, it may be time to consider replacing it.


No Response From Your AC or Heater


Is your thermostat turning on and off, but your HVAC system isn’t responding? If you’ve ruled out problems with your HVAC unit as the source of the issue, then the likely culprit is a non-responsive thermostat. The following reasons could be the cause:


  • Weak or Dead Batteries: Again, if your thermostat is acting up, it could be a battery issue. Install fresh batteries to confirm or eliminate it as the source of the problem.
  • Poor Wiring: Loose, dirty, or disconnected wiring can give rise to a multitude of problems — and a non-responsive thermostat is one of them.


Room and Thermostat Temperature Mismatch


It may feel unnaturally hot inside your home despite your thermostat saying it’s 68°F. Or you may be freezing inside while your thermostat displays a toasty temperature. If there’s a mismatch between your thermostat and the room’s actual temperature, you may have thermostat problems. Possible sources of the issue include:


  • Temperature Settings: Problems within the thermostat can render it unable to read the set temperature correctly.
  • Faulty Sensors: Temperature sensors may be acting up or failing if they fail to recognize the room’s current temperature, rendering each area too hot or too cold.


Looking For Thermostat Replacement Parts Online


Often, when you have problems with your thermostat, it can be a matter of simply replacing the damaged component to restore functionality. To identify the specific part you want to replace, look at your thermostat’s operating manual. You may also look for your model’s specification sheet or technical information online to find what specific thermostat parts you need to purchase for a replacement.


Once you’ve secured the correct information, you can scour online directories and distributors to purchase these parts. Unfortunately, if your thermostat is more than a few years old, there is a good chance that it’s out of circulation and the manufacturer no longer offers support. 


In this case, looking for replacement parts online becomes even more challenging due to the scarcity of materials. This means it will require significant time and effort to find what you’re looking for, so continue to be patient.


Restore Comfort In Your Home With Value Controls


At Value Controls, we are committed to helping you create a comfortable environment at home. Instead of spending countless hours online looking for replacement parts, look through our certified pre-owned and new thermostats to save time, money, and effort in finding the right thermostat for your home. Contact us today to learn more about our products and services.


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