Gas and Oil Home Heating Furnaces - Furnace operation flowchart
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bausin
12-02-05, 04:05 PM
It seems that a lot of questions and confusion could be avoided if this forum had a flowchart in a "sticky" message.
There is an example at http://www.mobilehomerepair.com/FurnaceFlowChart.htm
I'm not sure that one is 100% accurate. It says the blower doesn't turn on until the temp limit switch reaches 140 deg. and there were several msgs to Ravi saying the limit switch doesn't affect blower operation.
Just an idea,
Steve
There is an example at http://www.mobilehomerepair.com/FurnaceFlowChart.htm
I'm not sure that one is 100% accurate. It says the blower doesn't turn on until the temp limit switch reaches 140 deg. and there were several msgs to Ravi saying the limit switch doesn't affect blower operation.
Just an idea,
Steve
Jay11J
12-02-05, 04:46 PM
That flow chart is using the wrong word...
On older system. they used a control called a Fan Control/Limit
On the fan control/limit does two things.
1-Turn the fan on when the heat exchanger gets to a set point that the control is set at. (only 120volts)
2-if the fan don't turn on, the dial then keeps going up to the limit set point, and turns off the burner. (these some times control the 24 volts or 120volts)
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On some older/low end equipement, uses a metal disc that turns on the fan, and also another for limit for the burners.
On most newer equipement uses a timer that turns on the fan. and still uses these disc for limit control on the burners.
On older system. they used a control called a Fan Control/Limit
On the fan control/limit does two things.
1-Turn the fan on when the heat exchanger gets to a set point that the control is set at. (only 120volts)
2-if the fan don't turn on, the dial then keeps going up to the limit set point, and turns off the burner. (these some times control the 24 volts or 120volts)
---------
On some older/low end equipement, uses a metal disc that turns on the fan, and also another for limit for the burners.
On most newer equipement uses a timer that turns on the fan. and still uses these disc for limit control on the burners.