The sensor, often a simple bimetallic spring, responding to heat rising from the heat exchanger that is being heated by the burner, mechanically rotates the temperature dial component of the fan limit switch.
Safety Circuit Description for a Goodman Furnace.
Thanks to reader Rob for pointing out the confusion about the fan control auto - manual switch positions on the fan limit control.
The fan limit switch is designed to prevent this damage by shutting off the burner if plenum temperatures reach the high limit.Some limit control models do not include this white button or switch to give manual control over the fan.One reader has written that he finds limit controls at which the fan is put into manual continuous "ON" mode by pushing the switch in - though we have not found such cases.An advanced design and strong construction ensures an impressive and consistent performance.As the air lexmark x5470 instruction manual in the furnace plenum warms up the bimetallic spring expands, turning a gear which turns the fan limit control dial (shown in the photo above).This limit guards against burner flames not being properly drawn into the heat exchanger.The structural dynamics for engineers buchholdt pdf fan limit switch senses the temperature increase in the furnace.When does the furnace oil burner, gas burner, or other heat source turn OFF in normal operation: On many warm air heating systems, at least during cold weather, the burner or heat source will continue to run all of the time that the building thermostat.The gas fired forced air furnace fan limit switch in the photo above is pointed-to by a red arrow.The blower fan starts when the fan limit switch turns.Green links show where you are.
We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects.
IntelliFire Ignition System with wall switch constantly monitors ignition and ensures safe functioning 36" wide fireplace adds enjoyment to your space.
Check the control as follows: Allow the furnace to operate with burners firing continuously for approximately ten minutes.
Because your furnace uses an integrated control module (an electronic device that controls all furnace operations) it is certainly possible that the control module, which monitors all of the safety circuits, is not permitting the unit to run with your modification to the safety limit.Click to enlarge any image, the fan limit switch is a control which determines when the hot air furnace blower assembly turns on and off.But just want to know why the heater works but not the air conditioner with the limit switch bypassed.If the furnace oil or gas burner is very high capacity, or if the furnace fan/limit controls have been set to cause this effect, the burner may on some systems cycle on and off periodically while the warm air blower continues to run.The Goodman Furnace model PGB048075-1 is a mid-efficiency natural gas furnace with an afue rating.