I installed two silenx fans to replace the original a few years ago. I typically only run one of the two unless the outside temp is above 80 degrees, then I start the second one using an alligator clip. Been running them this way for the past three years without any troubles, even when the temp is in the high 90's. Why do I generally run just one? Because it's very quiet where we camp and I hate the sound of anything running.
With warm weather already here in Arizona our fridge compartment fan kicked on the other day and of course it is noisy. I have a little in-line lamp switch going to it but I thought it needs a quiet fan.
So I put this one in its place, seems to move near as much air as the original but you can't hear it inside and it's real, real quiet outside.
Are you running it with the speed reduction in place (1200 rpm)? I installed this same fan in mine, 1200 seemed to not be moving much air, so took out the speed reduction and am running at 1500 rpm. I started this project around 5pm and turned on the fridge right after I had everything wired and the fan mounted. When I went out this morning, the refrigerator was already at 39 degrees. At 1500 rpm, I can just barely hear the fan running, with the speed reduction in place, the fan cannot be heard.
I may reduce the speed again and see how much air is moving.
Didn't touch the speed. You're correct that it doesn't move a lot of air, but the fridge stays at 38 degrees with one fan in normal outside temps, I installed the second fan as a precaution for hot days. There's no noise with the one fan, very little with two and I usually check to confirm the fan is actually running (just being paranoid).
I really doubt there was any real CFM engineering that went into the original fan. I think they just wanted to move some air and put in any old fan that was priced right. So I think any replacement fan is likely to do just fine. Of course the more air you move, the more efficient the cooling will be.
I think I saw in some Dometic information, that it is the fan supplied/recommended by Dometic for their refrigerators when double side wall vents are used by the manufacturer of the RV.
So, for CYA safety, Airstream uses the fan that Dometic recommends, that way Dometic warrantee remains valid.
It is still a stupid system (my opinion of course) compared to the no fan vent through the roof.
I agree with some comments I'm reading here. Considering the build quality of an Airstream, and their reputation, I am aghast that a simple detail like fan notice hasn't been addressed. We payed out the nose for these trailers - why include a noisy $7.00 fan, if a $20.00 unit will be near silent? Cutting corners like this drives me nuts.
I am likely going to mount another silent fan in my rig, in order to run both when temps soar, or to provide a quick switch if one "buys the farm."
I really doubt there was any real CFM engineering that went into the original fan. I think they just wanted to move some air and put in any old fan that was priced right. So I think any replacement fan is likely to do just fine. Of course the more air you move, the more efficient the cooling will be.
To clarify, I was trying to say Dometic used any old fan. And I just checked my Silenex- it's 90 cfm.
Airstream authorized my dealer to install a lighted rocker switch inside the trailer on the wall opposite the rear of the fridge in our 2014 23D. It was the same switch installed near the door on the 2013 19s.
We have control over when the fan is powered. However, I wonder how wise it is to override the thermostat control that activates the fan. But....a good night sleep is a priority.
I want to replace the OEM fan with one that has the same specs, CFM and RPM. I bought a Silenex but the 3 electric leads were not well marked and we couldn't get it to power on.
Could anyone suggest a specific model that would fit my needs and has clearly marked wiring? Thanks.
Airstream authorized my dealer to install a lighted rocker switch inside the trailer on the wall opposite the rear of the fridge in our 2014 23D. It was the same switch installed near the door on the 2013 19s.
We have control over when the fan is powered. However, I wonder how wise it is to override the thermostat control that activates the fan. But....a good night sleep is a priority.
I want to replace the OEM fan with one that has the same specs, CFM and RPM. I bought a Silenex but the 3 electric leads were not well marked and we couldn't get it to power on.
Could anyone suggest a specific model that would fit my needs and has clearly marked wiring? Thanks.
Here is a link to a post that I did that explains the wiring on unmarked Silenx fans. I used this to figure out which wires to connect when I did our mod.
Airstream authorized my dealer to install a lighted rocker switch inside the trailer on the wall opposite the rear of the fridge in our 2014 23D. It was the same switch installed near the door on the 2013 19s.
We have control over when the fan is powered. However, I wonder how wise it is to override the thermostat control that activates the fan. But....a good night sleep is a priority.
I want to replace the OEM fan with one that has the same specs, CFM and RPM. I bought a Silenex but the 3 electric leads were not well marked and we couldn't get it to power on.
Could anyone suggest a specific model that would fit my needs and has clearly marked wiring? Thanks.
I really like the Noctua NF-S12B fans. They are the 120 mm, and should be the same size as your fan. They're quieter and less expensive than Silenex.
They probably will not push as much air, though, as your original fan unless you install two of them. My OEM fans (Mechatronics F1238M12B) pushed 105 CFM each, the Noctua fans are ~60 CFM.
It also helps a lot if you use a rubber gasket between the fan and housing and use rubber isolators instead of screws to hold the fan in place. Both are available from Amazon and are relatively inexpensive:
I just installed the Noctua fan and the difference is amazing. From unable to bear the noise to no noise at all.. I did only order one so now a second one is on the way. I used the original brackets with pieces of thick rubber (from square couch foot pads bought at Home Depot for $3) in between them and the trailer frame, and rubber grommets on either side of the new fan because it is thinner. As it happens I have another set of these brackets (because you can't just get the thermostat switch) so I will be installing the second one later this week to make up for the lost CFM.
I can't agree more on the Noctua fans. I actually have five of them. Two 120mm, 1 90mm next to those two (a 120 wouldn't fit on the right side), and two smaller ones up at the top even with the fins blowing out the upper vent (not sure of the size).
I put in 4 rocker switches in an overhead cabinet to let me turn them on and off (they're always off until the temperature sensor on the fins closes).
When I had the fridge out, I discovered that there was nothing between me and the fans but some 1/8" plywood when I was sitting in the dinette using my computer. I added some Noico soundproofing panels to the enclosure.
Now, even when all 5 fans are on, I have to put my ear up to the wall to tell if they're running or not.
BTW, the reason my 1200LRIM fridge was out was that the Norcold cooling unit failed and began to leak ammonia. I could smell it and could see the telltale yellow powder that precedes a fire.
I replaced it with a helium-filled unit from RvCoolingUnit.com. Not only is it *much* safer, it cools much better as well.
This is a great thread. Thanks to all for posting your experiences, ideas, and pictures. I am in a similar boat with a side vented refer on a '15 Signature 23D. The collective knowledge in this thread is a great help in devising and implementing a solution.
I am going down the path of upgrading the fan to the reduce the noise. I have ordered two Silenx EFX 12-15 to mount in the upper compartment to replace the OEM Freight trAiN.
I had just recently noticed that the refer fan was continuously running during our trip occurring in late June to Fort Robinson State Park in western Nebraska. High temps were in the low 90's, and the fan ran all day and all night. This was only our third trip with the AS, so we had not noticed the noise in the much cooler Spring Montana weather. Yes, highly annoying. Back in MT, the fan does shut off running on shore power when the ambient temp drops, so I do not think I have a thermostat issue yet.
This really ticks me off. Not the fact that the fan is noisy (yes, irritating, but can be solved with a quieter fan), but the fact that it has to run all the time (temps in low 90's!) to cool the compartment properly. This smacks of poor engineering and design, which is what many folks on this thread have addressed with the construction of a plenum to properly channel the air flow.
So, I got out the OEM supplied installation instruction for the Dometic refer and found on page 7 (of my manual) the requirement of a maximum (that's right, maximum not minimum) 1-inch gap between the back refer compartment wall and the back refer coil.The manual goes on to point out that if a maximum 1-inch gap to the back wall is not available, then a "box baffle" should be installed that creates this spacing and that this baffle should terminate in the upper access compartment within 1/2-inch of the condenser fins as shown on page 10 (of my manual).
Well, I go open and look up into the lower louvered outside refer compartment in my AS and what do I see? A 6-inch gap between the outside wall and the refer coil with a deflector plate mounted on the outside wall positioned to channel the air flow toward the coil. A deflector, not a baffle. Now, once this air makes it around the deflector plate, it will again choose to the path of least resistance and short circuit flow from the coil area. On top of this, the distance from the deflector plate edge to the back of the refer is over 2-inches (not the 1-inch prescribed by Dometic), so really what does that leave us with?
Back to the folks who have modified the compartment to provide a better air flow to the fins. I believe this is the key to preventing the fan from running continuously (provided the thermostat on the fins is functional). And, I believe, this is due to the poor design on Airstream's part by not following the guidance provided in the Dometic refer installation instructions. Am I looking at this correctly? Please jump in and correct me if I missed something.
My path forward is to install the two Silenx fans in place of the one OEM fan in the original fan location, and monitor the performance of the new fans. If these continue to run excessively, I will consider modifying the air path with the installation of a plenum or box baffle in order to better distribute the air over the coil.
At the vintage AS rally in Gunnison CO last year there was a presentation about refrigerators which was very well done. The man who presented it (sorry, can't recall the name now) talked about adding a deflector plate to direct the air as the Dometic manual suggests. He may have talked about a baffle as a substitute, as the Dometic manual indicates, but they are hard to install in a curved sided rig like the AS.
I spoke with him later and he said the deflector plate is critical. I looked at my FC 20' and it is there, but shorter than the width of the box plus the extra space on the side of the refrigerator cabinet, so air can bypass at the side in my unit.
He also suggested that the fan location at the top of the refrigerator is not the best place, but said that at the bottom, drawing in cool air and forcing it into the cabinet, up through the baffle and then out the top would be better than trying to pull the air out at the top the way the fans are now located. So blowing air in the bottom rather than sucking the air out at the top.
I have not done any experiments one way or the other. I did change my fan out for a quieter one.
He also made a big point, and demonstrated this, that overcooling of the top most dimpled pipe (above the upper fins) could in fact cause less refrigeration and poor box cooling. You would have to see the presentation to understand why, but he made a very convincing argument and backed it up well with a real unit to prove the point.
At the vintage AS rally in Gunnison CO last year there was a presentation about refrigerators which was very well done. The man who presented it (sorry, can't recall the name now) talked about adding a deflector plate to direct the air as the Dometic manual suggests. He may have talked about a baffle as a substitute, as the Dometic manual indicates, but they are hard to install in a curved sided rig like the AS.
Thanks for posting this. Just to be clear the Dometic manual only specifies the "box baffle" option. I will include the exerpts for reference. Certainly, the box baffle could be installed in the initial manufacturing process. A retrofit will be tricky, but possible with a thin and flexible sheet material.
Quote:
Originally Posted by idroba
I spoke with him later and he said the deflector plate is critical. I looked at my FC 20' and it is there, but shorter than the width of the box plus the extra space on the side of the refrigerator cabinet, so air can bypass at the side in my unit.
He also suggested that the fan location at the top of the refrigerator is not the best place, but said that at the bottom, drawing in cool air and forcing it into the cabinet, up through the baffle and then out the top would be better than trying to pull the air out at the top the way the fans are now located. So blowing air in the bottom rather than sucking the air out at the top.
Locating the fan in the lower section makes a lot of sense and reduces the recirculation potential. Not enough room in the lower compartment to get a fan directly below the coil, but an angled installation could work by the looks of it.
Quote:
Originally Posted by idroba
I have not done any experiments one way or the other. I did change my fan out for a quieter one.
He also made a big point, and demonstrated this, that overcooling of the top most dimpled pipe (above the upper fins) could in fact cause less refrigeration and poor box cooling. You would have to see the presentation to understand why, but he made a very convincing argument and backed it up well with a real unit to prove the point.
Interesting. Overcooling caused by cold ambient air temps?
Here is my interim fix for the fan noise. I used 1 fan initially (the one on the right about 36cfpm), but it did not move enough air, so I scrambled through the spares box and found another (60cfpm). Hopefully this is enough. I do have another 60cfpm fan I can switch in place of the first one if needed...
If this works out, I will make a better mount, but the zip ties and double sided tape are fine for proof of concept.
Still plan to add the switch inline too...
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Here is my solution mounted a few years ago. The key is to mount the fans close to the condenser fins and wire power into the temp switch mounted against the upper pipe so the fans run whenever the boiler is active. You'll never know when the fans are operating based on your ears alone. I have had great success with maintaining the proper operating temperatures in the reefer no matter what the exterior temp registers:
3 Arctic F12 fans 120mm, 0.25A max, 74cfm max each. Set up in parallel for a total of 0.75A max on the 1A fuse.
They move plenty of air, use less current and are far, far quieter than the stock POS.
Still need to add switch to the interior, purely for convenience and not for noise management.
Tempted by the plenum....
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Mad Astrophysicist turned sales guy that works to fund his dirty snowboarding habbit, mwah-ha-ha . . .
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