Why Does Your Furnace Shut Off Before Reaching Temperature?

Why Does Your Furnace Shut Off Before Reaching Temperature?

In a furnace, when Carbon and oxygen are reacted together, it releases Carbon dioxide and heat as the reaction is exothermic – it releases toxic heat generating particles. The Limit Controller measures the heat and prevents it from reaching the maximum level.

Most of the time, the limit controller turns off before reaching the limit in normal operations. The problem is normal some of the time. However, there may be some defects in the Limit controller. It is always preferable to keep an expert with you.

Filters for furnaces keep the furnace mechanisms clean while also removing pollutants from the air you breathe. Call for a regular heating tune-up in San Bernardino to maintain a good furnace. Fibreglass, polyester, and cotton are some of the materials used to make filters. The type of material used in the furnace has an impact on how well it filters the air.

The Reason Why The Furnace Shuts Off

  • Dirty filters: If you don’t replace the air filters frequently enough, they will become congested and filthy, causing the heat exchanger to hold heat and eventually overload.
  • Closed or obstructed air supply vents: Examine your air vents to determine if any of them are blocked or obstructed in any form if your furnace continues switching off. Even in areas you don’t even use, you must keep all of your vents open.
  • The blower wheel is filthy: The furnace may be turning on and off too quickly due to a dirty blower blade. The blower wheel contains blades that push airflow, and if they are clogged with dirt, they will not operate as well, if at all.

Where is The Limit Controller on The Furnace?

The limit controller is mostly present in the downside of the furnace. The same problem might arise with the furnace too. For this, contact a furnace repair in San Bernardino.

Furnace Turns Off in Normal Operations

When the thermostat has been satisfied, and the oil or gas burner at the furnace has been turned off, its limit switch will cause the instrument to operate just until. The temperature in the supply chamber has surpassed or fallen below the switch’s cutoff point. It will, after that, be turned off via the control.

The Limit of Containers

Some of the limits of fan or limit container are:

  • Fan off is the minimum temperature where the furnace blower fan will shut off to keep cool air out of the room. 90°F is a typical factory setting.
  • Fan on: the temperature at which the blower fan will turn on and begin delivering heat to the inhabited regions of the building. 100°F is a typical factory setting.
  • Fan limit: the temperatures where the high limit switch opens (turns OFF) to turn off the burner and protect the heat exchanger from overheating and damages.

Typical manufacturing temperature: 200 degrees Fahrenheit The heating furnace limit switch prevents the furnace blower from sending frigid air by turning off the fan until the supply air plenum is heated.


Our team of professionals at Daniels Heating and Air Conditioning will do all possible furnace repair in San Bernardino, working properly and effectively throughout the year. Never hesitate to call us (888) 523-2643 for your assistance.

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