Fridge humming

[MSGirl]

Is it normal for thefridge to hum? not super loud but can hear it 40' from camper if quiet outside.

2014 work & play 30 wrs

[limblips]

Originally Posted by MSGirl

Is it normal for thefridge to hum? not super loud but can hear it 40' from camper if quiet outside.

2014 work & play 30 wrs

Only if it doesn't know the words.......

Does your fridge have an auxiliary fan behind the outside access cover? Shouldn't be enough noise to hear it that far away.....

[raspivey]

Originally Posted by limblips

Does your fridge have an auxiliary fan behind the outside access cover? Shouldn't be enough noise to hear it that far away.....

You wouldn't think so, but mine is that loud. In fact, I'm actually going outside right now to pull the cover and see how many / what size so I can replace them with quieter fans.

[TURBS]

You won't find fan.
It's up in the wall.

[MSGirl]

Originally Posted by limblips

Only if it doesn't know the words.......
.

LOL!

It does sound like a fan. Just making sure that's "normal" . Pre- cooling it to leave this afternoon on our first outing w this toyhauler and didn't notice it humming last night. It's cooling good & got icecream waiting on us in the freezer!
Thanks for the replies!

[BandJCarm]

E flat is ok.

High G is bad.

[raspivey]

Originally Posted by TURBS

You won't find fan.
It's up in the wall.

Mine's in the slide so it's easier to get to. It's a single 92mm Sunon computer case fan between the the upper and lower panels on the outside. Cheap junk. There's room for two 120mm fans. I just ordered two replacements for $25 shipped. The factory fan is 4.7W pushing 70cfm at 4500 rpm and 45dBA. The new one's are 1.32W each with 74cfm each at 1400 rpm and 15dBA. That's roughly twice the air flow with half the power consumption and almost half the noise. Win all the way around. Should take all of 15 minutes to swap.

[OldCoot]

Mine is in the rear wall, but I put dual fans just above the burner and blow air across the entire rear of the frig.

[mikkeeh]

My frig is in the slide, and the fan is quite loud. Are most of these fans 12V ?

[keith_h]

My fan is mounted behind the upper vent. The one originally put in by Palomino was part of a fan kit supplied by Dometic. It was very loud. I replaced it with a somewhat higher CFM and much quieter fan. I am thinking of adding another near the lower vent to try to force more air over the condenser coil to improve hot weather performance.

[keith_h]

Originally Posted by mikkeeh

My frig is in the slide, and the fan is quite loud. Are most of these fans 12V ?

All of the ones I am aware of are 12VDC. Mine is thermostatically controlled to go on when the the outer condenser plate hits 95 degrees.

[SlowrideHD]

Interesting thread. My refrigerator is obnoxiously loud. Have had other campers and would never hear the fridge running.
I haven't dug into these systems much but I'm fairly handy. Anyone have a picture of the fan location in my Cedar Creek 34 RLSA? I have the back off the unit so I can see a limited amount of internals. Would gladly replace it with one of the suggested more efficient and quiet fans if I can get to it.

Anyone have a picture of the stock fan and location?

[raspivey]

Pull the top cover on the outside. The fan(s) are generally between the upper and lower portions. I had to get on a ladder and look down into the lower compartment to see it. According to my wiring diagram, some units have two fans some don't. The problem is 1. They are cheap fans. 2. They are ball bearing type which are a little noisier and draw slightly more power than some other types. 3. They're mounted horizontally which, with these types of bearings, can make more noise. If it's like mine, they are just 92mm computer case fans. Mine has mounting holes for two fans but the holes aren't going to line up with the bigger fans I'm installing. I'll have to modify it slightly (which might amount to just using one mounting screw and a dab of Gorilla glue on the other....). Get fans with fluid dynamic bearings...usually about $10 at any computer parts place.

These are what I ordered. One will put out the same airflow as my old one, but at 1/3 the power and noise ratings I'm just going to double up.

SilenX EFX-12-15 Case Fan-Newegg.com

[SlowrideHD]

Thanks so much.

Just watched an exceptional utube video by Ray of Love yourRV which showed how he replaced his fan.
Best utube video I think I've ever seen....mostly because it showed me exactly what I needed to know.
Thanks Ray.

[SlowrideHD]

[QUOTE=raspivey;1314322]Pull the top cover on the outside. The fan(s) are generally between the upper and lower portions. I had to get on a ladder and look down into the lower compartment to see it. According to my wiring diagram, some units have two fans some don't. The problem is 1. They are cheap fans. 2. They are ball bearing type which are a little noisier and draw slightly more power than some other types. 3. They're mounted horizontally which, with these types of bearings, can make more noise. If it's like mine, they are just 92mm computer case fans. Mine has mounting holes for two fans but the holes aren't going to line up with the bigger fans I'm installing. I'll have to modify it slightly (which might amount to just using one mounting screw and a dab of Gorilla glue on the other....). Get fans with fluid dynamic bearings...usually about $10 at any computer parts place.

These are what I ordered. One will put out the same airflow as my old one, but at 1/3 the power and noise ratings I'm just going to double up.
[end quote]


I looked at mine a bit more using a mirror to see down inside from the top vent opening. The bracket my little cooling fan is mounted to has another set of empty holes right next to it. I'm glad they didn't put two of these noisy little suckers in there.
So if I remove that large piece of thin plywood from just under the condenser fins, will I be able to get to the fan and wires easily? It is right in the middle of the top and bottom wall openings. Seems that would be easier than pulling the entire fridge out to replace the fan. But I've never done either one so I don't know which is the easiest way to go.

[richp]

Hi,

I left the upper fan in place, and installed a much quieter one on a home fabricated mount at the bottom of the compartment -- separately switched from the upper fan.

It pushes air up nicely through the chamber behind the refer, and across the cooling fins. This approach means that the stock fan is still there for a time when exceptional cooling needs might arise.

FWIW.

Rich Phillips

[raspivey]

Originally Posted by SlowrideHD

I looked at mine a bit more using a mirror to see down inside from the top vent opening. The bracket my little cooling fan is mounted to has another set of empty holes right next to it. I'm glad they didn't put two of these noisy little suckers in there.
So if I remove that large piece of thin plywood from just under the condenser fins, will I be able to get to the fan and wires easily? It is right in the middle of the top and bottom wall openings. Seems that would be easier than pulling the entire fridge out to replace the fan. But I've never done either one so I don't know which is the easiest way to go.

Sounds like yours is identical to mine. I'm going to just make cuts on that thin sheet and bend it out to get access and then just tape it back up into place. All it's there for is to help direct airflow across the fins. It may not be REAL easy to get to, but it's doable. I certainly wouldn't pull the unit out.

[SlowrideHD]

So I have been following all of these threads about replacing the Dometic cooling fan with something more quiet, or with more air flow, because of the loud humming noise that emanates when the fan is running.

I will recap some info for those newly joined to this discussion.

1. My fridge is a Dometic RM3962LBFX installed in the driver side slide out.
2. Since it is installed in a slide-out, it has two vent panels, one at the bottom which is typical for any RV fridge, and one at the top to provide an escape for heat coming from the condenser fins at the top of the unit.
3. There will be a cooling fan mounted on a horizontal piece of aluminum bracket that is centrally located between the bottom and top panels. The fan installed in my unit was a computer case type fan by ADDA, model AD0912UB-A71GP. Specs on this fan are 92 x 92 x 25 size, drawing 0.46 amp (4.68w) at 60cuft/min and noise level rated 39 dba
4. The fan will be triggered to run by a T24 series thermostat that was attached to the far right side cooling fin with two screws. The thermostat in my unit was a T24 B 055-15. This is rated to close at 131 F with a 27 F operating range.

This is what I have discovered so far. I removed the piece of thin plywood that covers a large portion of the upper vent opening. I did this to gain easy access to the fan. I was able to use my drum brake adjusting spoon as a pry lever to pry the piece of wood away from the wall of the compartment. It is just held in place with some small wood staples and caulking.

Then I removed the two screws that hold the fan to the aluminum bracket. My bracket has a couple sets of holes evenly spaced. It looks to be designed to easily hold 2 fans of the same size and spacing in a side by side (horizontal) orientation.

I also removed the two screws that hold the thermostat to the right side of the cooling fins. Then by removing the ground wire and unscrewing the fuse holder on the positive side wiring, I was able to remove the fan for testing. Keep in mind that there was quite a bit of noise from this fan inside the RV when it was running. Outside it did not seem so loud because of being masked out by background noise outdoors.

I hooked the fan to a couple different 12V sources to listen to it run and check its operation. It was practically noiseless when running unmounted and resting on my workbench or when resting in my battery compartment. I was completely surprised at how quiet it was.

So I turned the power back on to the refrigerator yesterday (I had previously turned it off while I removed the fan) and let it cool down to operating temperature overnight. I did this with the top panel removed and the piece of wood that serves to direct all the fan airflow over the cooling fins, also not installed. I just let this piece of wood slide down into the mid section rather than tear it up trying to get it out of the space. This morning the temperature was 36 degrees in an empty fridge. I had set the control to "4" so it would get colder than mid-range. I wanted to generate a lot of heat from the boiler.

I reinstalled the fan (minus the thermostat in the circuit) and hooked it back up to the 12V source and ground. This way I was assured it would run without relying on the thermostat to close. Guess what? Just as noisy as before. I was amazed.

So as far as the loud humming noise, it seems to be a function of being mounted to that long thin aluminum bracketry. And also its position within the space.

Some thoughts are: That while the piece of wood serves to direct all the fan airflow closely to the cooling fins, it also eliminates a good bit of the cover openings to allow the hot air to get out. Leaving this wood piece out seems to be a tossup (to me) of less air directed to the fins but more outlets available in the cover for heat to escape. Its design (by blocking over half the vent openings) seems to me to assure that the fan is occasionally needed, perhaps more than necessary. Also, it does not seem to effect the noise level from outside or inside the living space (the wood piece)

So where do I go from here? Logically, even if nothing else changed, I would .want to put a thermostat bypass in the circuit to insure a constant fan supplied air flow when desired. Like when you load the fridge with groceries and first turn it on (maybe not as soon as optimum). I think this would help for a quicker cool down when there is high heat load inside the fridge

As soon as I can today, I intend to unmount the fan from the long bracket to determine if there is another mounting method that will lesson the noise.

[Davidceder]

Raspivey;

Can you post a link to the fans you purchased? It would be appreciated.

[OldCoot]

I suggest mounting dual fans just above the burner in the lower compartment and blow air across the entire back of the frig including all the tubing. I would leave the plywood that previously blocked the top completely out. I put a simple toggle switch on the fans.