Panasonic WhisperGreen fan: problem or feature?
I’ve recently installed a Panasonic WhisperGreen bath fan, and I’m not sure if it’s working properly. It will run for a while, then stop for about 30 seconds, then restart. Is it supposed to do this? It’s on a timer switch now, but it was originally on a simple on/off switch and it did the same thing.
On any other fan, I’d assume it was faulty and return it, but this is a model that waits 20-30 seconds after you turn it on as it slowly spins the fan up to speed, which this forum says is a feature and not a bug. Maybe it’s a DC motor characteristic? Or maybe it’s some kind of calibration for the sensor that adjusts air flow?
Thanks for any help you can give!
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You don't have the motion or condensation sensor modules installed, correct? With the time delay module, the fan can be set to run continuously as a low speed and then accelerate to a higher speed with the fan switch is turned on. Is this what you mean by "on a timer?"
The DC fans are super quiet at low speed and turn on. With my fans, it takes about 20 or 30 seconds for them to ramp up to a speed that is audible (to me). That is normal behavior.
Thanks, Steve. No, I don't have any of the modules installed. The timer I referred to is a generic wall switch that lets me turn the fan on for 10 minutes, an hour, two hours, etc. If I set it for an hour (or any length of time), it will initially take 20-30 seconds to ramp up, as you say. Then some time later -- maybe 15 minutes maybe 45, it varies -- the fan will shut off. Then 30 seconds or so later, I'll hear it ramping back up, and it will run for the remainder of the programmed time. I did contact Panasonic about this, and no response.
A lot of models are built with the timer as a standard module. I suggest removing the grill and checking.
There are no modules. My questions remain, for the dozens of people on this forum who have recommended the Whispergreen fans: does anyone else experience the fans shutting off for about 30 seconds, then restarting? Would something about a DC motor cause this? Would it be related to the advanced feature that varies fan speed to assure it meets the stated CFM output?
From the wiring diagram, it looks like most units include two red wires for adding a signal switch. If you don't use this switch but connect the red wires to power, that can damage the fan.
I have a similar Panasonic vent fan. It does take a long time to ramp up. I vaguely remember reading that it spends the first ten seconds or so looking for a timing module. If it doesn't find one, it then starts slowly ramping up. After 20-ish seconds, it runs normally.
The problem is that guests don't know about this, and when the fan doesn't work immediately, they turn the other switches on and off, and end up not using the fan. I had to label the fan switch with a 20 sec delay note.
I tried putting a timer control switch, but it didn't work with the fan...can't remember or not sure why, but I had to go back to a conventional toggle switch with a label. I know this doesn't address your first question, but that's been my experience. Once the fan does run, it works well and is acceptably quiet.
Same experience here. Slow to start up, but never had it shut down once running.
I have two WhisperGreens and they don't do that run, pause, run more pattern that Nola mentions. I would think it's a fault but don't know the units in depth.
Nope, I don't notice shutoffs during fan runs.
Exactly what model number do you have? What is the model of the wall timer?
Mine does the normal slow ramp on startup. My Lutron wall time has a "feature" where it shuts the fan off for a second with a minute to go as a warning. This doesn't work very well with the slow speed ramp of the fan and I wish I could shut it off.
I have the Panasonic FV-11-15VK2 WhisperGreen. I don't know the wall timer make or model (bought at HD, guessing it's Lutron), but it's not a one-minute warning -- it sometimes does this 5 minutes into a 30-minute run. Also, I noticed this stop-start behavior the first day I installed the vent, when I was using a simple on-off wall switch.
I'm going to experiment and see if it's more or less frequent with windows open or other house vents engaged -- to see if the stop-start might be related to the feature that adjusts fan speed to maintain constant CFM flow. Maybe I'm occasionally creating enough negative pressure inside with windows closed and other vents running that I'm making the vent's brain stop and recalibrate. My house isn't especially tight, but if someone's cooking and the kitchen hood is running, I could see an issue. I hope to update this in a few weeks. Thanks to all for the help!
Oh, one thought is these fans use very low power. Does this timer have a neutral connection or is it wired like a normal switch on the hot leg? I wonder if the amps through the fan are too low to keep timer relay latched?
Edit: you said it did it on a standard switch. I would swap replace the fan. With same model it should be easy.
I just retrofitted a FV-0511VKS2 Whisper Fan. Mine came standard with a module. I think the higher end ($$$) do - it has a timer on it and a fan speed. This is the component that I had to REMOVE from the fan as it is programmed to run 24/7 at low speed. Point is to eliminate need for human interaction to activate fan - mainly for moisture reasons.
https://www.amazon.com/Panasonic-FV-VS15VK1-Whisper-Select-Plug-Multi-Speed/dp/B00JALSFN4/ref=asc_df_B00JALSFN4/?tag=bingshoppinga-20&linkCode=df0&hvadid=&hvpos=&hvnetw=o&hvrand=&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=&hvtargid=pla-4583589101719993&psc=1
Once removed, I re-set the breaker to assure the fan computer also had been reset (not sure you have to but just in case). What I found is that the wall crank timer I have would turn fan on but then the fan would keep running at low speed continuously. Basically, the crank timer did not Turn Fan off - somehow there is still low voltage coming through.
SO - next step is to change out the old crank timer.
I have the same fan in my master bath and use a non panasonic timer that has 5, 10, 30, 60 minutes, 2 and 4 hours on it. This is how I use that fan and it works beautifully - a certified electrician installed so thinking my issue is my wiring or the old crank timer is not a good match for the Panasonic.