Son of Fermentation Chiller - Electronics High Pitch Whine

I recently build the Son of Fermentation Chiller and noticed that my fan seems to make a high pitched whine when it's not running. The components I've purchased are:

12 volt DC Computer Fan (Radio Shack model 273-243B)
Enercell AC Adapter 1.5 – 12 volt (Radio Shack model 273-315)
Honeywell Thermostat from Home Depot (Model # CT31A)

I've connected everything as the original Son of Fermentation Chiller guide recommended. Fan Negative (Blue) to Adapter Negative (Written Wire), Fan Positive (Red) to Thermostat G, and Adapter Positive (Blank Wire) to Thermostat R.

The circuit works exactly as intended. When the thermostat is set to On the fan runs continuously. When set to Auto the fan turns on when the ambient temperature is above the thermostat's setting. The Adapter is set to 12 volts and the thermostat is set to Cool.

Whenever the thermostat is set to auto and the temperature is below the thermostat's setting (Fan is not running) I hear a very high pitched whine or squeal coming from the circuit. I believe it's coming from the fan though I'm not entirely sure. This happens immediately when the adapter is plugged in and the thermostat is set to a very low temperature. When either I switch the thermostat to On then back to Auto, or when the thermostat is on Auto and I raise the temperature setting then lower it again, either way turning the fan On then Off again essentially, the whine takes about 1 second to build then settles into the familiar high pitched noise again. I heard nothing with the thermostat set to Off.

Does anyone have experience with these components, or circuits in general? Any ideas on what could be causing the whine? More importantly, is it anything to worry about? I'm cautious to utilize the electronics until I understand what's causing the noise. Any help is appreciated. Thank you.

I am having the exact problem with my set-up. Didn't see a response, and was wondering if anyone had advice/input?

Disconnect the fan and then put your ear against the wall wart...and then the thermostat...

Cheers!

Sometimes cheap switch-mode power supplies, which I'm assuming is what you have, make that noise when they're working.

Cheers,
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Don

Hi idylldon, you mean even when the component isn't operating, just while power is flowing they'll whine? If so that's good to know.

An update for Deb, I never figured out why my setup produces this noise. In all my googling when I first constructed the chamber I only found one other person on another forum using the same components. I messaged him asking if his chamber was also producing the noise and he said yes but he'd never had any problems so he didn't worry about it. I've used mine now for over a year, never had a problem. I don't know if it's safe, just never had an issue. Hopefully idyll's response means it truly is nothing to worry about.

Thanks for reviving this thread, at least I know I didn't just mess up my connections, or if I did I'm not the only one.

Fresh95 said:

Hi idylldon, you mean even when the component isn't operating, just while power is flowing they'll whine? If so that's good to know.

Click to expand...

Yes, some of them will whine a bit when current is flowing. Since it's only powering a small fan, it should have the capacity. Just make sure the fan doesn't draw more than the DC adapter is rated for.

Cheers,
--
Don

Hey all. I thought this might be the best thread since I'm building with mostly the same equipment as listed by the first poster.

Honeywell Thermostat from Home Depot (Model # CT31A)
Insignia 120 mm case fan from Best Buy (assume 12V although does not say)
Old Vonage 12V plug

I've wired it as specified here but have had no luck. Some potential mis-wirings:

1) The wires from the Vonage plug were not marked red and black. One of the wires had a dashed white line on it, so I assumed that was the red (+).

2) The computer fan has 4 wires, 2 of which are grey, 2 are black. After looking at a number of images online, I assumed that the outermost wire on the clip side (see photo) was the black, and the next inner one was red.

Any thoughts or suggestions? I wanted to be sure that the mechanism works before jumping into the fermentation chiller construction.

Thanks!

Taquina said:

1) The wires from the Vonage plug were not marked red and black. One of the wires had a dashed white line on it, so I assumed that was the red (+).

2) The computer fan has 4 wires, 2 of which are grey, 2 are black. After looking at a number of images online, I assumed that the outermost wire on the clip side (see photo) was the black, and the next inner one was red.

Click to expand...

Okay, I decided to connect the fan directly to the adapter to see if I could get it to run on the wires I selected. It did not run. I stripped all the wires and tried multiple combinations to no avail. Then I realized that my adapter does not say "DC" on it. Yikes!

So I found an old adapter from my shaver that reads 12v d.c. I connected it to the fan and it worked immediately! The DC adapter only goes to 400mA and the fan seems to not run at its full potential velocity. I also tried to switch the wires to see if the fan would run better the other way around (backwards), but it only runs one way.

Should I use a higher mA adapter if I can find one? What is the typical req for a 120mm computer fan?

Thanks.