5 Ways to Tell if Your Home's Thermostat is Malfunctioning

The performance of your heating and cooling systems depends on the thermostat. Thermostats detect the temperature in a room and compare this room temperature to the set temperature, increasing the heat if the room is too cold and delivering cool air if the room is too warm.

Sometimes when your air conditioning unit does not regulate the temperatures in your Marin area home, it is possible that your thermostat is malfunctioning. Over time, the thermostat could break down, and the solution is usually a replacement. Before you apportion the blame on the furnace or central air conditioning system, check your thermostat first.

Young man sitting at desk with face in front of fan

1. The switch on your fuse is defective.

Ensure you turn off your thermostat. You will find a lever or button located at the bottom of the thermostat; this is the “On” and “Off” switch. Turn this switch to “Off” position. If the switch is not working, test the fuse, and if faulty, its time for a replacement. You will need the furnace and gas working to test the heater, ensure the furnace power is on, and gas is on. The access panels to your furnace should be easy to remove, just lift up and pull right out.

At the control board on every furnace is located the terminal strip, where all the wires of the thermostat are connected, find these cables. Cut a length of insulated wire and strip insulation from each end of the wire. You must first check to confirm that your thermostat is in the “On” position before you proceed. Like any other electrical gadget, you must turn it off whenever you see any signs of trouble.

Do not attempt to repair the AC without the help of a professional. Ensure that you understand the different settings such as “Heat” or “Cool”, and check whether your AC is responding when you turn the dial. If you own an automated thermostat, then you need to check for any possible programming overrides on the thermostat program to confirm that overrides, if any, are not the problem impeding the operations of your thermostat.

2. The furnace is working when you remove the thermostat.

You should now test the heating cycle in the furnace. Connect one of the wire ends to the W terminal and the other end of the R terminal. If the furnace starts up normally, then the malfunction is in the thermostat. And if your furnace does not start then the fault is most likely in your furnace.

If you identified that the problem is your thermostat, replace the thermostat. If you determine that the furnace has a problem, it is better to call a professional technician. Remember to put the access panels back on your furnace.

3. Failure to Respond to the Switch

Set your thermostat to five degrees higher than normal during winter and to five degrees lower than normal during summer. You must hear a clicking sound when you turn your thermostat either to five degrees above or below normal. Wait for a few minutes to see whether your return vents will suck in air, or your supply vents will blow out the air.

If your device does not function properly, ensure your thermostat working properly and set it to either “Cool” or “Heat”. Also, set the air conditioners’ main circuit breaker “On”. Turn “Off” the circuit breaker and remove the thermostat cover to check the wires, secure the cables to their respective mounting screws, and reattach any loose wires you may find.

4. Improper Connections

Ensure that you turn off the power supply to your air conditioning unit because the following procedure could prove quite dangerous. You should be able to see the wires beneath the thermostat cover once you have taken off the cover, just gently pry the lid to remove it.

Now, choose wires that correspond to your problem, red and green wires for the cooling problems, and red and white wires for the heating problems. Unscrew from the thermostat the two wires you choose, remove them from the terminals then wrap them around one another.

Reconnect your heating and cooling system to the power supply and watch keenly. If you had a heating problem and the blower and burner turn on, then your thermostat is faulty, and if you had a cooling problem and the fan turns on, then your thermostat is faulty.

Marin, CA thermostat-repair5. Bare Wires

Turn off your main circuit breaker and remove the cover from the thermostat to expose the wires beneath. The risk of electrocution is minimal because thermostats operate on very low voltages, about 24 volts.

Take a photo of the wires in the thermostat before any disconnections. You could use your phone to take the pictures. The pictures are critical for the re-connection of the wires, a process that might prove quite confusing to most of us. Unwind the screws with the labels "R" or “Rh” and “W”, disconnect the wires, and loosen the bolts. Twist all ends of the wires together and turn on the furnace circuit breaker.

If the furnace turns on, then the thermostat is faulty and needs replacing, and if the furnace does not turn on, then it is the furnace that is defective. For furnace repairs, it is advisable that you call a professional technician.

If your thermostat repair was successful, you should hear a clicking sound emitting from your thermostat; your partner should also listen to a clicking sound emanating from the furnace. In the case that your furnace does not emit the clicking sound then your thermostat is not sending any signals, and you need to replace the thermostat. If the thermostat does not emit a clicking sound, then the furnace is defective, and you need to call a technician.

Consult a Professional

During the summer, your air conditioning system may fail to cool the air, or during winter, it may fail to heat up the air, and you might conclude that your air conditioner is faulty.

While thermostat repair operations are quite tricky, an experienced HVAC technician in Marin County can install a programmable thermostat effortlessly. Ask a professional to assist you since the prospect of replacing or troubleshooting your programmable thermostat is not for the faint-hearted.

While this task is not a DIY operation, you can work hand in hand with your HVAC technician and understand the nuts and bolts of air conditioning. Understanding the troubleshooting process can give you plenty of insight and allow you to know when your thermostat fails.

For thermostat installation services in your Marin, CA home call Bellows Plumbing, Heating & Air at (831) 219-8644.