Re: Furnace Blower Fan Cycles On/Off During the off Cycle
Reality check, refer to the furnace manual posted on the first post. There are 2 styles of motors used on this furnace. One style of GMP uses a standard 3 speed motor. This series should be straightforward to troubleshoot, especially when we find out which speed is coming on during the intermittent operation.
The GMP models ending with "E" actually have electronic, or "ECM" motors that have electronically controlled speed (infinite). That series will have a more complex control board and more expensive motor. So, once again it appears we are dealing with a standard 3 speed motor as per your description above?
Next, flip through the .pdf you posted and determine which of the 12 GMP diagrams apply to your present furnace - that would certainly help. If in fact you have a 3-speed motor, the most common failures are going to be 1)motor capacitor and 2)loose solder connections on the pcb motor relay terminals. The order of troubleshooting steps matters.
So, what kind of motor? Which diagram? What speed is intermittently coming on and off?
Reality check, refer to the furnace manual posted on the first post. There are 2 styles of motors used on this furnace. One style of GMP uses a standard 3 speed motor. This series should be straightforward to troubleshoot, especially when we find out which speed is coming on during the intermittent operation.
The GMP models ending with "E" actually have electronic, or "ECM" motors that have electronically controlled speed (infinite). That series will have a more complex control board and more expensive motor. So, once again it appears we are dealing with a standard 3 speed motor as per your description above?
Next, flip through the .pdf you posted and determine which of the 12 GMP diagrams apply to your present furnace - that would certainly help. If in fact you have a 3-speed motor, the most common failures are going to be 1)motor capacitor and 2)loose solder connections on the pcb motor relay terminals. The order of troubleshooting steps matters.
So, what kind of motor? Which diagram? What speed is intermittently coming on and off?
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