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Lennox M193 - high fan speed in 'fan on' position

I am used to having 'fan on' running the fan in high (same as when cooling) speed to move air around the house.
Currently, fan speed in low (same as heating speed).

How can I change it to a higher fan speed with the thermostat switch at 'fan on' (no heat, no AC)?


  • ZmanZman Member Posts: 5,826
    I don't think it is built that way, so you would have to devise a work around. This would almost certainly void your warrantee.
    Start by checking with tech support to see if they know of a way.
    I clever controls person with a DPDT relay could make this happen.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • HVACNUTHVACNUT Member Posts: 3,350
    The ECM motor is controlled by the board in the furnace. There is a bank of dip switches to set fan speed.
    Check the manual.
  • STEVEusaPASTEVEusaPA Member Posts: 4,134
    Is there some other problem, is the system working properly?
  • John Mills_5John Mills_5 Member Posts: 935
    If this is a ML193UHE, you can easily rewire the low voltage terminal strip to make the constant fan run at cooling speed. Is that something you can handle? Otherwise a sharp tech can do it.
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