Bathroom fan oscillates when turned off

[vdotmatrix]

I installed a panasonic bathroom fan FV-LP002 about 14 years ago. I was getting ready to do some cleaning maintenance to it, when i noticed the fan spinning around Slowly, but not fast. I pulled a permit for this bathroom project…

at first i thought it was a convection from a/c vent…or power from led night light….i shut both off and it still spun around.

i went to the breaker and only then did it stop.

Can i fix this easily?

What could I have done wrong? All the other circuits in the bathroom work and outlets are wired correctly.

Any ideas? Thank you.

 

[Duke74]

was the fan motor actually making noise? I am wondering if the wind outside was blowing accross your fan vent pipe and it drew air from your bathroom through the fan and spun it. It quiting when you shut the breaker off might just be a coincidence. Does it start spinning every time when the breaker is on?

 

[vdotmatrix]

was the fan motor actually making noise? I am wondering if the wind outside was blowing accross your fan vent pipe and it drew air from your bathroom through the fan and spun it. It quiting when you shut the breaker off might just be a coincidence. Does it start spinning every time when the breaker is on?

Yeah, no coincidence. I thought of all Those variables already. The speed of rotation is a constant. I flip the breaker and it stops. It is not turning with any velocity, but it is a constant.

I thought of shooting a 15 sec. boring video of a bathroom fan turning but thought better of it.

thanks for responding.

 

[Duke74]

Yeah, no coincidence. I thought of all Those variables already. The speed of rotation is a constant. I flip the breaker and it stops. It is not turning with any velocity, but it is a constant.

I thought of shooting a 15 sec. boring video of a bathroom fan turning but thought better of it.

thanks for responding.

you’re welcome. It could be your switch. Switches will fail from time to time. I would start with taking the fan switch out of the box and touch the wires together, see if it runs at full speed and it should stop
100% when the wires are apart.

 

[vdotmatrix]

Power to the fan in the ceiling is connected with a clip. The fan itself is on a timer….the switch itself could be leaking Through, though it says it is off….I think I could replace that switch…. Sounds like a likely scenario.

 

[Duke74]

I would start with the switch

 

[unslow1]

Again like everyone else I've seen a bad switch do this.

 

[vdotmatrix]

I had a similar issue that I reported on another post that involved an LED light and a lighted wall switch…with the LED light dimly lit after it was switched off….so, i see this timer switch also has tiny LED, but the voltage is slightly enough to turn this fan.

 

[vdotmatrix]

Well the SOB still oscillates when it is suppose to be off. It cost me about $35-42 for a new switch. It aint the switch. Probably the most logical place to begin if I were Spock. It has probably spun around at low speed for years and I didn't notice it. I am getting too old for this kind of aggravation right. Lol

 

[nadogail]

Sounds like a problem for both Scotty and Spock.

 

[SALIV8]

Does this fan have a control board?
does it have a remote?

ive had to remove the control board on one of mine that was acting up and just straight wire it to a switch.

id at least meter the wires to see the voltages when off.

 

[vdotmatrix]

Does this fan have a control board?
does it have a remote?

ive had to remove the control board on one of mine that was acting up and just straight wire it to a switch.

id at least meter the wires to see the voltages when off.

There will be no rewiring on this voyage away from the galaxy. No remote.

This is Panasonic bathroom exhaust fan.

Pretty strong but very quiet. So quiet and strong that I but in a slightly larger one in the upstairs bathroom ( this is off when I turn it off).

I will write the panasonic division that makes these as a last resort.... Thanks everyone.

 

[engineer2]

Panasonic fans of that era used potted electronics. They had issues with the potting material shrinking over time and stressing/damaging the electronic components. On mine it caused the lighting circuit to fail. They sent me a new part under warranty. Contact Panasonic for their advice.

 

[vdotmatrix]

Panasonic fans of that era used potted electronics. They had issues with the potting material shrinking over time and stressing/damaging the electronic components. On mine it caused the lighting circuit to fail. They sent me a new part under warranty. Contact Panasonic for their advice.

I will. That era! hahaha. It was not all that far back. this one has a night light, exhaust and the bathroom light. The one upstairs I ran a separate 20A circuit for the heater, but also has the night light, fan and light.....wisper quiet...120 cfms? I fergit.

 

[ripperd]

Well the SOB still oscillates when it is suppose to be off. It cost me about $35-42 for a new switch. It aint the switch. Probably the most logical place to begin if I were Spock. It has probably spun around at low speed for years and I didn't notice it. I am getting too old for this kind of aggravation right. Lol

Does your switch have a neutral?

If not, it is likely drawing a tiny amount of power through the fan motor to power itself. That's how any electronic timer/switch control works if it doesn't require a neutral.

 

[vdotmatrix]

it doesn't have a neutral. 2 blacks and a ground.... The other panasonic fan upstairs has the same switch, wired the same and the motor doesnt turn....perhaps it needs a different threshold.... anyway....i dont care just concerned about a fire issue.

 

[justsam]

I found this statement in a product description for your timer:

" Exhaust fan must meet 0.3-amp minimum load requirement to be compatible; substitute MA-T51MN (item #742099) if the exhaust fan load is minimum 0.05-amp."

As posted by ripperd, there is a small amount of current being drawn through the motor windings causing it to turn. The switch model mentioned above is actually for a 3 way, which you do not need, but what it does have is a neutral, which eliminates the path as described by ripperd. Now the question is, do you have a neutral in the box?

Why is it happening to one fan and not the other I suspect is just a threshold issue. We are talking small amounts of current here and one fan may have better bearings or less friction in some way, but I suspect both are drawing a small current through the windings.

 

[Forgottonia]

Do you have a clamp-on ammeter? If you found out which wire is feeding current into the motor you could probably isolate the problem. (If you don't have an ammeter you could start pulling wires off to find out which one is the culprit.)

 

[csp]

I know you've already replaced the switch, but if it were mine I would still verify it isn't a switch issue, and not with another $42 type. Use a simple on/off switch just like the one that turns a light on and off. Those either have a connection or they don't, there is no leakage or electronics that could be part of the problem.

 

[justsam]

I know you've already replaced the switch, but if it were mine I would still verify it isn't a switch issue, and not with another $42 type. Use a simple on/off switch just like the one that turns a light on and off. Those either have a connection or they don't, there is no leakage or electronics that could be part of the problem.

I guess in affect it is a "switch issue" since I believe it is due to the solid state switch that is being used in the design of the timer. If the timer used an electromechanical switch, such as relay, there would not be an issue, same as with just using a toggle switch as you mention.

 

[Duke74]

Take the 2 blacks off your switch and touch them together. That way it will act like a normal toggle switch and you’ll know for sure if the switch is the problem.

 

[vdotmatrix]

Do you have a clamp-on ammeter? If you found out which wire is feeding current into the motor you could probably isolate the problem. (If you don't have an ammeter you could start pulling wires off to find out which one is the culprit.)

Always wanted a clamp on ammeter, so I could learn how to use it.

 

[vdotmatrix]

I know you've already replaced the switch, but if it were mine I would still verify it isn't a switch issue, and not with another $42 type. Use a simple on/off switch just like the one that turns a light on and off. Those either have a connection or they don't, there is no leakage or electronics that could be part of the problem.

This sounds like a reasonable experiment!

 

[Forgottonia]

Always wanted a clamp on ammeter, so I could learn how to use it.

Ha ha! That's how I've gotten almost all my tools! My rationalization is that, if I get this tool for a particular task rather than hiring it done, the tool will pay for itself.

 

[justsam]

Do you have a clamp-on ammeter? If you found out which wire is feeding current into the motor you could probably isolate the problem. (If you don't have an ammeter you could start pulling wires off to find out which one is the culprit.)

Few clamp on ammeters available or used by the DYI person is going to be able to detect the few milliamps of current being drawn, even if you put multiple wire turns around the clamp. The current being drawn is the amount necessary to power the solid state timer since it must draw it's power through the load, in this case the fan motor winding, since his switch being used has no neutral.