I am retrofitting a used Osburn 1800 wood insert .
when I plug in the fan unit to test it, at room temperature of about 75F, it does not turn on.
investigating further there is a small High Limit Switch (the size of a dime ) which does not have continuity.
when I bypass that switch and apply power directly to the fan motor, it works fine.
so, is my high limit switch defective?
a quick read suggests that a HLS should Open and Close at certain temperature points.
would it be normal for a HLS to be OPEN at a low temp, like 75F? does it CLOSE at a high temperature?
hmmm, reading a bit further, it seems there might bethree TWO temperture points in the switch.
1. below which the switch stays OPEN so the fan does not function and blow cold air.
2. when the heat gets to a warm enough point it closes so that fan is blowing warm air
3. a very high temperature at which it OPENS again to turn the fan OFF. IGNORE THIS THIS MAKES NO SENSE as has been pointed out. I
must have misread something
does that sound about right?
If so, then it would be normal that my fan would not work when just plugged in at 75F ambient temperature.....
when I plug in the fan unit to test it, at room temperature of about 75F, it does not turn on.
investigating further there is a small High Limit Switch (the size of a dime ) which does not have continuity.
when I bypass that switch and apply power directly to the fan motor, it works fine.
so, is my high limit switch defective?
a quick read suggests that a HLS should Open and Close at certain temperature points.
would it be normal for a HLS to be OPEN at a low temp, like 75F? does it CLOSE at a high temperature?
hmmm, reading a bit further, it seems there might be
1. below which the switch stays OPEN so the fan does not function and blow cold air.
2. when the heat gets to a warm enough point it closes so that fan is blowing warm air
must have misread something
does that sound about right?
If so, then it would be normal that my fan would not work when just plugged in at 75F ambient temperature.....
Last edited: