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Electric Switch Problem

3chordcharlie

3chordcharlie

Diamond Member
I've got a bathroom fan which has been working nicely on a switch, but I'm a little tired of coming home to find it has been pumping heat (i.e. $$) all day because I forgot to turn it off after my shower.

So I went out and bought a timer, single pole, 5A rated (no neutral wire in box, fan is rated at 1.25A). http://www.levitonproducts.com/catalog/model_6515M.htm

I wired it up, turned it on, and the fan started humming, but not working, so I turned it off right away. The fan motor seems to be burned out, but now I see the package also says 'Incandescent only'.

I'm guessing the switch refused to provide the startup amperage for the fan (which I would have thought was under 5A, but maybe not)? Any ideas here?

This is starting to get expensive!
 
You need the 6215-w switch for fan motors. Try the old switch the motor may not be burned out. If it is you may be able to buy a replacement one.

Good Luck...
 
Just glue one of those wind up kitchen timers next to the switch and tape a chopstick to the timer wheel so that the timer flips the switch. Simple. Effective. Cheap. Everyone knows this.
 
Fiat1 said:
You need the 6215-w switch for fan motors. Try the old switch the motor may not be burned out. If it is you may be able to buy a replacement one.

Good Luck...
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Thanks, at least now I know!

The motor is definitely burned, unfortunately. It looks pretty replaceable, since it is a standard two-prong plug into the fixture. So I might get this done without digging through a foot and a half of insulation that I just put in the attic!

I've already got the 20A version of the switch, also useless to me. At this point I'll be pretty glad to have this all done for $150, or 5x what I thought it was gonna cost🙁
 
Whoa, those are neat little timers... I want one!

My exhaust fan has a heater circuit as well.
When you turn on the heater, it also turns on a second fan motor that blows hot air down.

I guess I would need the fan motor version as well.

Thanks for serving as an example for others! 🙂
 
edro said:
Whoa, those are neat little timers... I want one!

My exhaust fan has a heater circuit as well.
When you turn on the heater, it also turns on a second fan motor that blows hot air down.

I guess I would need the fan motor version as well.

Thanks for serving as an example for others! 🙂
Click to expand...
As far as I can tell, the way I'm wired, I can't use either timer. There's no neutral wire to use, and the 5A version is NFG, so apparently TFP is actually offering the best solution for me🙁
 
I don't see why an undersized switch would cause the motor to burn out.
Like you said, the fan motor is only 1.25A.
Incandescent elements have high inrush currents as well.
 
edro said:
I don't see why an undersized switch would cause the motor to burn out.
Like you said, the fan motor is only 1.25A.
Incandescent elements have high inrush currents as well.
Click to expand...

Startup must be well over 5A though; all I know for sure is it worked before with the regular switch, and now it doesn't. Unless there's a replacement fan with a very low startup draw, I'm stuck with $65 worth of useless switches, and I need to go buy a motor, and an egg-timer style switch (which I will make damn sure is the right kind!).

I sure hate pissing away money on stuff like this. It seemed like such a quick easy job!
 
Inrush currents can be very high for a short period. That 1.25Amp might be the run amp but is easy to expect that the inrush current 200 to 500%

Most of those semi digital timers use a solid state gate to control that AC and may burn very quickly during that inrush. Also incandescent lights are still a 'wire' so the switch can pull a little current to operate which it can't do as well with motors or ballasts.

Odds are the older style twist timers like they use on Jacuzzis would work fine / better.
 
imagoon said:
Inrush currents can be very high for a short period. That 1.25Amp might be the run amp but is easy to expect that the inrush current 200 to 500%

Most of those semi digital timers use a solid state gate to control that AC and may burn very quickly during that inrush. Also incandescent lights are still a 'wire' so the switch can pull a little current to operate which it can't do as well with motors or ballasts.

Odds are the older style twist timers like they use on Jacuzzis would work fine / better.
Click to expand...


This. The OP installed a TUNGSTEN ONLY timer on a shaded pole motor. It's really no different than installing a tungsten only dimmer on a fluorescent fixture. If you must have a push button type timer be sure to purchase one rated for motor loads. The twist type is nothing more than a spring wound timer that has a tripper at zero that opens up a set of contacts. These are fine just make sure if you only need a minute or two to turn it all the way THEN set it to the time. This assures the spring is wound enough to have enough umph to open the contacts at zero. Otherwise it may stall and the load runs and runs leaving you wondering what the heck can possibly be wrong with such a simple contraption!

More sophisticated controls use a motion sensor. When someone turns on the fan the motion sensor is active. When it no longer detects anything the timer starts which can be set for whatever period you like. This way if you come back two minutes later the fan doesn't shut off too early, etc.
 
The missing Neutral wire in the switch box is a common problem in these situations. It starts with a history of the circuit. The cable from the fan to the switch has only 2 current-carrying conductors (black and white). Usually it is hooked up so the black is joined at the fan to the fan's incoming Hot line (from the breaker), and the white from the switch cable is joined to the fan's actual Hot input wire. The fan's Neutral is connected to its supply side white (Neutral). This means the cable from fan to switch has an Always-Hot (black) and a Switched-Hot (white) coming back, and no Neutral. Worsk great for a simple switch. ALSO works well if you have a MECHANICAL timer that has only two terminals from its switch, just like a simple manual switch.

SO that is one solution: look in the store for a MECHANICAL older timer that works with just a twist of the timer knob on the front, and has only two electrical terminals for connection to your switch box wires.

I did the update you did - with the electronic timer of this type. (However, I'm pretty sure it had a rating over 5 amps.) BUT I recognized that this new timer type needs a real Neutral line into its box also to connect to the timer's Neutral terminal. So I replaced the short cable from fan to timer box with a length of 14/4 cable (black, white and red conductors plus bare Ground). At the fan it is hooked up: black is HOT fed from incoming power (from breaker), white is Neutral fed from incoming Neutral (also tied to Fan motor Neutral lead), red is Switched Hot (coming back from the timer) and connected to the Fan's Hot side wire. At the timer box it's then simple to connect up all three terminals of the timer, and it works just fine.

NOTE: I am not sure at all on this part, but it is possible that the problem you are having with the fan motor now is JUST because the timer has no Neutral line to use. MAYBE the timer is NOT putting out the full power needed because its own internal circuits are incomplete. If you're careful NOT to touch the wrong thing and electrocute yourself, try these quick checks:
1. Pull the timer out of its mounting box so you can get at the terminals. Take a piece of insulated wire with bare ends and simply connect together the two terminals with the black and white wires attached. This simulates the normal closing of the old simple switch you used to have. If the fan suddenly starts and runs this way, there is nothing wrong with it.
2. Disconnect that short and turn the timer on. The fan hums, right? Use your wire to connect the timer terminal that is supposed to be for Neutral (it has no wire on it) to the metal box. IF the box has a good Ground in it, this will provide a short-term substitute Neutral connection for the timer. That might enable it to function properly and feed power back to the fan. Does it start up and run? If so, that proves you need to provide a real Neutral to the timer. OR you need a different (maybe older mechanical) timer instead.
 
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Is it just me or has the op already spent more on switches than for forgetting to turn-off the fan?

Also, if the fan is rated for 1.25A, wouldn't that mean the max amps is 1.25A including the inrush currents and that the steady current is significantly less?
 
highland145 said:
All home projects cost 5x and take 3x longer than expected. Everyone knows this, too.🙁
Click to expand...

Yep lol. I can relate to that, when I bought my house. I went like 10k over budget with the renovations lol. Was worth it though.

Dimmers "chop" at the sine wave, so maybe this caused the motor to not be able to turn propery if it depends on the 60hz sine wave.

Motor dimmers just lower the voltage, I think... I could be wrong.
 
citan x said:
Is it just me or has the op already spent more on switches than for forgetting to turn-off the fan?

Also, if the fan is rated for 1.25A, wouldn't that mean the max amps is 1.25A including the inrush currents and that the steady current is significantly less?
Click to expand...

The OP certainly has spent much more on this project than I stand to save in the next several years.

I bought a new motor (actually, just a new fan, then transplanted some guts), a mechanical switch (the exact kind I didn't really want, which is where this all started), and have it all running properly now.

So total cost of new, working parts: $27.

Other parts:

20A digital timer (couldn't use, no neutral wire in my wall) $27
5A digital timer (not rated for motor, fried fan motor, but interestingly, not switch) $30
new exhaust fan to replace fried one $32

total: $89

All prices are before 13% sales tax here in Ontario, and no price is attached to the 5-6 hours and 3 trips to the Home Depot this all took.

If anyone wants two mostly unused, pushbutton timers in the K-W Cambridge Guelph area, they're all yours. If nothing else, I can guarantee they take no offense to excessive cursing, and severe, if empty threats.
 
You can return anything to Home Depot. As long as you have the credit card you bought it with. They'll take everything. Amazing return policy.
 
citan x said:
Also, if the fan is rated for 1.25A, wouldn't that mean the max amps is 1.25A including the inrush currents and that the steady current is significantly less?
Click to expand...
1.25A is the FLA (Full Load Amps), which is what the motor draws under worst case normal running conditions.
Starting inrushes are anywhere from 2-5x that depending on the size of the motor.
LRA (Locked Rotor Amps) is a value for when power is applied, but the rotor is locked in place. Sometimes LRA is higher than starting inrush, but they are often times about the same.
 
Modelworks said:
No neutral ? who wired that ? Are they using just a hot and ground ? If so you got bigger problems than a timer.
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No neutral at the switch - I've got hot, switched hot (to the fan) and ground in the box; there's also a light powered from the same box, in the ceiling. I'm quite certain they just wired the neutrals directly to the fixtures, and not to the switch for convenience.

I've certainly found it to be convenient!
 
Modelworks said:
No neutral ? who wired that ? Are they using just a hot and ground ? If so you got bigger problems than a timer.
Click to expand...

Switch only boxes don't require a neutral to be drawn in to the box. Switches should only switch the hot side. Cheapo single pole switches have no use for neutral. It is only when you get the 'fancy' tier that you need it.
 
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