No medium speed on fan

[Bill_H]

I have a Casablanca floor model 19N8F fan, 110VAC. It has worked well for several years (and is out of warranty) until recently. It has a off-3 speed switch. Off works. Low speed works. Medium speed stays the same as low speed. High speed works. So it is missing the medium speed. I would like to fix it myself (I am a mechanical engineer and routinely do home wiring) - what should I look for when I open it up? Is a loose wire likely? What part am I likely to need? I am checking but I think Casablanca would just want to replace the whole thing ($$$) rather than fix it ($$).

Thanks! Bill_H

[paul52446m]

I have a Casablanca floor model 19N8F fan, 110VAC. It has worked well for several years (and is out of warranty) until recently. It has a off-3 speed switch. Off works. Low speed works. Medium speed stays the same as low speed. High speed works. So it is missing the medium speed. I would like to fix it myself (I am a mechanical engineer and routinely do home wiring) - what should I look for when I open it up? Is a loose wire likely? What part am I likely to need? I am checking but I think Casablanca would just want to replace the whole thing ($$$) rather than fix it ($$).

Thanks! Bill_H

Hi Paul here. i am not a fan man, but have done heating and cooling for 40 years. I guess you would have to find out is the motor an single speed with a speed controller on it or is the motor a 3 speed motor with 3 winding's in it?.
So it could be a rheostat bad, or you might have a bad winding. Of course like you said, you have to check all wires. Paul

[HayZee518]

Inside you'll see a square rotary speed switch with four wires on it. one wire is the line hot, the other three are speed wires that go to the low-med-high speed windings. yours may be as simple as changing the switch - or - the medium speed winding is toast. with an analog meter set on volts [120] check between each switch leg to the white wire.

[Bill_H]

HayZee - I haven't opened the fan up yet. I understand measuring the continuity of the switch in each position to each of the legs, but with no power in (unplugged). But measure volts with the fan hot? Did you mean measure ohms between the switch outputs and the white (fan neutral) and see if the medium speed winding is significantly different than the other two?

[HayZee518]

unplug the unit. remove the back cover. if its like a fan I got, the knob pulls off. it is keyed by a half moon shaft. the rotary switch may be fastened to the back cover or screwed in place over the end of the motor. its easier to troubleshoot by measuring the outputs of the switch with the fan HOT. one probe will go to the neutral [leave it here] rotate the knob one click at a time and measure the output from each of the remaining three wires. one of the wires will be the hot feed into the switch. you said you wired homes so measuring a hot should be no problem. measuring continuity is feasable but you'll read all sorts of readings, arc tracks, surface resistivity etc.