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rseagle · 04-23-2004, 05:02 PM

OK, let's do some Brainstorming here.

We like to Boondock and enjoy the peace and quiet of our favorite secluded mountain campground in the Summer. I'm afraid, that the noisy refrigerator vent fan in our 22' CCD is going to drown out the natural sounds we travel so far to hear. Our first trailer, an SOB, had a vent stack to the roof with no fan. It was dead quiet so we could hear the stream, Whip-Poor-Wills at dusk, Cicadas, wind through the trees, etc. You get the picture.

I've read of retrofitting the 12v fan with a 24v fan, which rotates at a slower RPM, but twice the Amps. It still makes noise.

I'd thought of fabricating a 4-6' metal or plastic vent stack that could be temporarily attached to the CCD when we get to the campground that would draw out the hot air behind the refrigerator. Is this practical? Could it work like my SOBs stack, so that the fan's thermostat would keep it from coming on?

Any other ideas from you "Out of the Box" thinkers out there?

Thanks,

Bob

mandolindave · 04-23-2004, 05:55 PM

My 1973 20' has an intake vent underneath the fridge and an exhaust vent on the roof. The original fridge had no fan. The new fridge has a fan. The
installer said that I really only needed the fan for hot days. I didn't
want to be running the fan and using up my batts so we are installing
a manual swith to kill the fan when I need too.
It would be nice if you could hear another trailers fan , to see if
you have a funky fan.

Turtle · 04-23-2004, 07:24 PM

I'm adding a switch to my refrigerator fan on my trailer tomorrow. Our trailer is so small you can't get away from the fan. As I've detailed on another (see thread "noisy refrigerator fan"), I moved our fan to a quieter location which really helped. We really only need to turn it off for sleeping.

MaShep · 05-02-2004, 11:03 PM

Hey Jamie:
Would be cool if you take a few pics of your project? I'm also wondering, how much noise does your water pump make when you turn on the faucet? Ours is extreemly loud!

Pahaska · 05-03-2004, 07:33 AM

The fan runs a lot faster than is needed. One approach is to put another 12v fan in series with the first; both will run slow and without noise. Another option is to put a resistor in series with the existing fan to slow it down.

Do a search ... there are a couple of long threads on the fan noise problem.

67caravel · 05-03-2004, 08:53 AM

Here's my solution for our '04 22' CCD fridge fan noise (quite loud!):

SilenX 120mm 11 dBA Fan $26.00
Part number: 0000375

11dBA is virtually silent.

I ordered it from EastLuna.com. According to my measurements, it should be a direct fit as a replacement for the factory original.

Best regards,

X

luckydc · 05-03-2004, 12:46 PM

X

Please let me know how that works out. Had the Bambi out boondocking this weekend. The fan ran contantly, I assume because the gas flame. Eventually, I had to discontent it and turn down the frig so I could sleep.

Very interested in the SilenX. Appropriate name, too!

luckydc · 05-03-2004, 12:55 PM

X:

Couldn't wait. Ordered one. Thanks for the tip.

rseagle · 05-03-2004, 02:19 PM

X:

Is this fan for Direct Current (DC) use? What is the amperage draw?

Bob

luckydc · 05-03-2004, 02:28 PM

Bob:

From the site:

SilenX fans are the perfect complement to SilenX power supplies in your system! Featuring a noise to airflow ratio no other fan on the market can touch (papst, panaflo and blacknoise don't even come close!), these are the perfect fans for your silent PC. Each SilenX fan comeswith silicone composite fan vibration dampening mounts, no other fan on the market comes packaged with such mounts! 3->4 pin convertor in included with every fan so you have the option of running it off the motherboard of the power supply, this is one amazing deal!
Features:
Fan Swept Forward Fan Blade Design
Smoother, Thinner Fan Blades
Highly Efficient Hypro Bearings
Vibration Isolation Mounts

Specifications:
Fan Dimensions: 120 x 120 x 25mm
Fan Input: 12V/1.2W
Fan Speed: 1400 RPM
Air Flow: 40 CFM
Noise Level: 11 dBA
Three Pin Connector
Four Pin Connector

What is the ampage of the factory fan? Boondocking this weekend didn't even put a dent in my batteries, so not certain I'm concerned about this fan being a big draw. I want quiet!

dtbw · 05-03-2004, 02:29 PM

This fan is for use in a PCs where all the fans are DC driven. The manufacturer's website specs this fan at 12V/1.2w so that mean 100ma of current. I have order a pair of these. I previously replace the factory unit with a lower rpm, high volume unit (a big improvment), but I think I can still improve it more with these fans. My hope is that with 2 running in series, I can virtually eliminate the refrig fan noise while still providing a good flow of air thru the refrig condensor.

david

rseagle · 05-03-2004, 02:51 PM

The Silenx fan looks like a good solution! Might have to give it a whirl. Sorry about the Pun!

I pose another idea: Could a rheostat (variable resistor) be used with the existing fan to slow the RPMs to a quieter speed? It might be a cheaper alternative then 1 or 2 Silenx fans $26 ea)?

Bob

dtbw · 05-03-2004, 03:14 PM

The factory fan is a plain vanilla design. The blades are not designed for quiet operation or large volumes of airflow. Slowing it down will cut some of the noise, but it cut the flow of air faster than the reduction in noise. You need a better blade design. As I mentioned, I already replace my factory fan with a lower rpm, high volume design, which made it much quieter inside, but outside sitting under the awning, it was still a nuisance. The key is lots of slower moving, high efficiency blades designed for quiet running. Putting two of these in series may still not result in quite as much airflow as a single unit running at full speed, but the air will be distributed over a greater area, so the result should be satisfactory cooling.

david

thenewkid64 · 05-03-2004, 04:27 PM

Quote:

Originally Posted by rseagle

I pose another idea: Could a rheostat (variable resistor) be used with the existing fan to slow the RPMs to a quieter speed? It might be a cheaper alternative then 1 or 2 Silenx fans $26 ea)?

Yes, but at the cost of loss of power. depending on the type of variable resistor or Potentiometer you use the loss in voltage is normally done by a resistor that generates more heat. So you get 70% efficiency to be quite but still have the same draw or load on the batteries. If you are boondocking it can make a difference. It will be a lower cost alternative, but as mentioned in other posts you reduce the airflow. The reduction in airflow can make the refer work harder to keep the food cold. I guess what I am trying to say is TANSTAAFL. You are going to have a cost somewhere. So I would go with 2 in series or the quieter fans IMHO.

Pahaska · 05-03-2004, 08:34 PM

Don't worry about the amount of airflow. The refrigerator is designed to work on thermal currents alone. Any fan at all and any amount of airflow is beneficial. A gale may do as much harm as good.

As important as the CFM of the fans is insuring that he fan is actually causing airflow over the fins. A fan hanging out in free space is pretty ineficient; it may be recirculating more air than it is moving over the fins. I made a baffle out of a piece of aluminum to make the fan more efficient on my International.

dtbw · 05-06-2004, 01:20 PM

My two silenX fans just arrived. 1st tried powering just one with 12V to see the max noise and air flow. Impressive, quieter yet than the lower rpm, high volume fan that I used to replace the factory fan, BUT there is no doubt that you would still hear it inside, to some extent. From the outside, the whir of the fan would still be noticable and annoying.

Then I put the two in series (electrically)...Virtual dead silence and a combined airflow in line with that producted by the single fan running at 12V. THIS IS THE TICKET to the condensor fan noise issue. Also having the two fans will do a better job of distributing the airflow across more of the condensor fins. I do think that I am going to make an aluminum plenum to mount the fans underneath the condensor and focus the airflow, plus a deflector to go above the condensor fins to direct the flow outwards to the door louvers. This will be vast improvement over the factory "afterthought". The plenum will also give me an area to "sit" the fans on so that I can use the rubber isolation mounts that are included. The isolation mounts, while great for noise, certainly do not offer any mechanical ruggedness, but if the fans are mounted horizontally with the support underneath the fans, then the rubber mounts should work fine.

Even at $55 for the pair (including shipping), this is a relatively inexpensive fix to a large annoyance.

david

Tin Hut · 05-06-2004, 02:31 PM

David, I look forward to seeing the fans. I need to do the same thing, not for noise, but for heat. I'll need to pick your brain on how and where you wired them into. Thanks.

rseagle · 05-06-2004, 03:45 PM

David,

Glad you got your fans. I was just out looking at mine. I hope to do the same thing with the Silex units. I'd love to see some photos of your install and plenums that your fabricate. Could you provide a materials list? Also, what size wire will I need to hook up the fans in series. I noticed the 2 DC voltage wires and the red & blue wires pinned to the refrigerator. Is that to the heat sensor? Whill that have to be connected to both fans or will it open the circuit for both?

Thanks,

Bob

67caravel · 05-06-2004, 05:27 PM

The SilenX replacement I just received and installed was a perfect match for the factory fan (i.e. holes lined up). I have not fired mine up yet but am hopeful that it will be "liveable" as-is with only one SilenX installed...

It was an E-Z install.

X

dtbw · 05-06-2004, 08:19 PM

Bob,

I will take some pics during construction and installation. I have started making the aluminum frame for the two fans to sit into. The plenum will actually just be a three sided affair as I am going to use the back wall of the refrig for the back wall of the plenum.

As for wiring, it is very simple. If you notice each silenX fan actually only has a red and black wire although they come with a harness designed to plug into a PC chassis. You simply cut off the harness leaving only the red and black wires. Then you will connect 1 red wire from one fan to 1 black wire of the other fan (solder and cover with heat shrink tubing). That will leave one red wire and one black wire which will be connected to the existing factory wiring. The factory fan circuti on the A/S is a simple series circuit where the positive first goes thru the on/off switch, then thru the thermodisc and then to the fan. The negative wire is a direct connection. In fitting the new fans, simply attach the red wire to wire leading to the thermodisc and the black wire to the remaining wire from the original install. There will not be any need for any new wire as the existing wires are plenty long.

It should be noted. This type of FAN works only with correct polarity. I am not sure if the silenX fans have reverse polarity protection, but if not, they can be destroyed by reverse polarity. That is why it is VERY important to connect the red wire from the fan pair to the wire from the thermodisc (follow the wire from the existing installation over to the thermodisc).

david