Fan heater blower never turns off

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starLED

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Fan heater never turns off blower, but the heating is turning on/off normally.
My guess is that the (rotary) switch is the issue.
Is that the case?

 
Is this a new occurance?, and do you mean as the thermostat switches on and off? - if so that's normal behaviour, thermostats usually only switch the element.
 
Thermostat should turn on/off both the heater and the blower.

I'll ask again, has this only just occurred?, it sounds like perfectly normal operation - certainly the one I'm sat near does that, and all others I've seen have (the fan continues to help prevent over heating of the element).

Just check how it's wired, it's hardly rocket science.
 
No, it's not normal. Normal is the element and blower work on/off at the same time.
It can be seen from the images that thermostat turns on/off power to the both.

I think I know what the issue can be.
When the element is heating, probably there is a partly broken wire (maybe part of element) somewhere that cuts off power to the element, but the blower remains on, so actually thermostat never reacts but when it cools down wire gets connected again and becomes conductive again and heats up element.
I have noticed some sparking in the element.
 
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I found the issue.
Overheating protection below the fuse is activating after 30 seconds of work (that's where the spark is occuring), and it cuts off current to the element.
Thermostat never reacts, that's why the blower keeps blowing.
I don't know if overheating protection is faulty or the element?
Fan heater did work for 3 years, it could be really element overheating.
 
Do the fan motor bearings need re-oiling? They often stiffen up over time, as the oil evaporates or thickens. The fan running too slow could explain the overheating, though it could also be the overheat protector that is messed up..

I use a bit of car engine oil to re-saturate the felt pads around the bronze bushes in typical fan motors such as those.
(It also works wonders in small equipment or PC fans etc.)
 
I don't see any issues with the fan speed.

I would test overheat protector, but I am not sure how, what parameters to use for test?
 
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