Where is the heat sensor in a furnace? You'll find it towards the back of the unit. Look for a rod-shaped device in the path of the burner—that's the sensor.
Locate the sensor, which is a small, round component usually positioned near the bottom of the thermostat. It may be labeled as “sensor” or “thermistor.” Using a soft brush or a can of compressed air, carefully clean the sensor to remove any dust or debris that may have accumulated on its surface.
The sensor's failure to detect a flame causes the furnace to shut down as a safety measure. Inconsistent heating: A faulty flame sensor can cause the furnace to cycle on and off frequently, leading to inconsistent heating in your home. You may notice hot and cold spots or a lack of comfortable warmth.
While sometimes a faulty sensor sends a permanent cold signal to the engine, it can also send a permanent hot signal. The computer will again miscalculate the signal and cause the engine to heat up instead of cooling it down. When this happens, the car might misfire, or it could lead to engine knocking.
If it's easy to get to, “Replacing a coolant temperature sensor is generally considered a relatively straightforward job for someone with basic mechanical skills and the right tools,” says Knoll.
Residential HVAC systems are typically equipped with a single thermostat. In most cases, these are located on an interior wall, about midway between the floor and the ceiling. This provides the best location to measure and control to an average temperature.
The average cost for an Engine Coolant Temperature Sensor Replacement is between $406 and $448. Labor costs are estimated between $97 and $122 while parts are priced between $309 and $325. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.
First, turn off the power supply to the furnace by turning off the breaker in the circuit box. Locate the reset button on the furnace and press it to reset the furnace. It is usually located inside the blower compartment on the side of the blower motor. Be cautious, as the housing may be hot.
Incorrect Temperature Gauge Reading
If the gauge or indicator reading is off by more than a few degrees, then the sensor is likely faulty.
A thermostat sensor is normally close to the evaporator coil inside the air conditioning unit. As the air passes over the sensor, it checks the current temperature of the air and compares it to the desired temperature.
A thermostat, by definition, controls a device based on temperature settings. A temperature sensor simply provides the temperature reading in either analog or digital form to another device, often a microprocessor, which uses temperature, possibly among other factors, to control a device.
Furnace flame sensor location
The sensor is located just outside the burner assembly and looks like a small rod with porcelain surrounding the end that connects to the burner.
Temperature sensors can last a long time, often several years, depending on their type and usage. For instance, thermocouples typically last 1 to 3 years, while RTDs can last 3 to 5 years with proper maintenance. In optimal conditions, some sensors might even last the lifetime of the equipment they are installed in.
Symptoms of a bad coolant temperature sensor:
Engine Overheating or Overcooling: A malfunctioning coolant temperature sensor can result in improper engine cooling. If the sensor provides a falsely low reading, the ECU may not activate the cooling fans or engage the radiator properly, leading to engine overheating.
Locate your temperature sensor next to your thermostat.
Attached to the thermostat or installed right next to it is the temperature sensor which looks like a small, black device plugged into a wire harness.
A common oversight for a thermostat showing the wrong temperature is the state of its batteries. Dead or low-power batteries can lead to inaccurate readings. Simply replacing the batteries might restore your thermostat's accuracy and functionality.
In summary, while the actual process of removing and replacing the coolant temperature sensor may only take around 5-10 minutes, additional factors such as preparation, draining coolant, testing, and cleanup can extend the total time to complete the job.
So where should you place temperature sensors in order to accurately report room temperature and properly control Heating and Cooling equipment? About 5 feet high on a column or interior wall in a central location with good circulation (though not too close to supply ductwork), with no hot or cold equipment nearby.
Yes, a bad coolant temperature sensor can often trigger a diagnostic trouble code (DTC) to be stored in the vehicle's onboard computer system.