behind-fridge fan questions

[tfarny]

Hi yall:
New owner of a 25 Flying Cloud here, bought it used mid-trip and am troubleshooting on the fly as we go. Lots of questions!!

In trying to make this new home of mine as comfortable and functional as possible for my wife and I, I'm trying to track down sources of annoying noise and parastic current draw where possible and minimize both. So far the most annoying thing I've found is the fan mounted behind the fridge, accessible from an outside hatch.

I understand that the purpose of this fan is to cool those cooling fins on hot days and I don't doubt it's needed on hot days. But ours was coming on seemingly randomly - camping in coastal California in March, with nights around 50f, it would come on in the middle of the night, etc. and was loud enough to wake us, a lot louder than a silly little 12v computer fan need be. I don't anticipate we'll be in warm climates for a while and I'd like to nail down a good solution to this while we are in this nice coastal weather zone.

I put my hand back there and the coils were just warm to the touch. I disconnected the fan, removing it completely, a couple of days ago and have been monitoring the temps informally - the fridge isn't struggling at all and I can still comfortably touch the cooling fins. I will replace the current fan with a quiet version but that still leaves questions.
My questions are:
1. is there a themostat controlling that fan, and if so, how can I set it to engage at a (much) higher temperature range?
2. at what temperature is my fridge going to start to struggle - ie how hot can I let it get back there with some margin to spare? or IOW, where would you set a thermostat to activate this fan in my shoes?
3. Why would AS set it up this way - is there something I'm not understanding here? I think of this thing as like the Mercedes of travel trailers but this definitely does not look like premium, well thought out engineering to me.
Thank you for all replies!
Tim

[field & stream]

Hi, and welcome to Airstreaming.

Your last point is kind of the key to all of the problems. As good as Airstreams are, their reputation for quality far exceeds the reality. It is easy to be among the best travel trailers if the competition is as weak as it is. Like all of the rest of us, you now have a new hobby of fixing and upgrading things you will think you shouldn’t have to do. Enjoy!

The fan noise problem is easy to fix by replacing the provided inferior one with one or two “silly little 12v computer fans”. They are wired to a thermostat, which may or may not be working properly (mine failed).

Regarding performance at higher temps, all propane fridges start to struggle around 90. I suggest you try to always keep the fridge temp towards the lower end because they really struggle to recover from getting warm.

[MSDeneen]

Originally Posted by tfarny

Hi yall:
New owner of a 25 Flying Cloud here, bought it used mid-trip and am troubleshooting on the fly as we go. Lots of questions!!

In trying to make this new home of mine as comfortable and functional as possible for my wife and I, I'm trying to track down sources of annoying noise and parastic current draw where possible and minimize both. So far the most annoying thing I've found is the fan mounted behind the fridge, accessible from an outside hatch.

I understand that the purpose of this fan is to cool those cooling fins on hot days and I don't doubt it's needed on hot days. But ours was coming on seemingly randomly - camping in coastal California in March, with nights around 50f, it would come on in the middle of the night, etc. and was loud enough to wake us, a lot louder than a silly little 12v computer fan need be. I don't anticipate we'll be in warm climates for a while and I'd like to nail down a good solution to this while we are in this nice coastal weather zone.

I put my hand back there and the coils were just warm to the touch. I disconnected the fan, removing it completely, a couple of days ago and have been monitoring the temps informally - the fridge isn't struggling at all and I can still comfortably touch the cooling fins. I will replace the current fan with a quiet version but that still leaves questions.
My questions are:
1. is there a themostat controlling that fan, and if so, how can I set it to engage at a (much) higher temperature range?
2. at what temperature is my fridge going to start to struggle - ie how hot can I let it get back there with some margin to spare? or IOW, where would you set a thermostat to activate this fan in my shoes?
3. Why would AS set it up this way - is there something I'm not understanding here? I think of this thing as like the Mercedes of travel trailers but this definitely does not look like premium, well thought out engineering to me.
Thank you for all replies!
Tim

The fan is ATTEMPTING to protect your fridge from over-boiling the amonia. However, as configured in stock Airstreams, it is not very effective. It blows directly ON the condensor fins - and is very inefficient, so it comes on a lot.



What is needed at the back of the fridge is a constant flow of air INTO the bottom of the compartment (lower door) and OUT through the upper end of the compartment (upper door). This requires TWO fans do do properly.



In the stock form, there is a bi-metal switch (relay) screwed into the right side of the fins. That is the "on/off" relay for the fan(s).



A really good primer on all this can be found at the web site for the "Fridge Defender" - which is a truly nifty thing to prevent damage to the fridge.



No affiliation - but I did purchase the full kit last week.



Cheers!


Mark

[SuperTrouper]

I'd start with a replacement the thermostat. Do a google search for this switch that turns on at 40C (104F) 36T22 561887 F40-15C S0750

Here's a good thread on fridge fans https://www.airforums.com/forums/f42...ig-211379.html

[Tim A.]

Our 2002 (purchased new) came with a single-speed single fan for the refrigerator coils. We soon replaced that with a multispeed, two-fan setup of European origin. When that died a couple of years ago, we installed this: https://www.amazon.com/dp/B09NLFDLD1...n_title_1&th=1. Works great and is quiet. We have a separate shut-off switch for it so we can make sure it is off when we are not using the refrigerator.

Tim

[Rich Jenkins]

I had one of those single-speed thermostat controlled fans in our new to us 2019 FC 25 RBT we bought last summer. I threw it in the trash and installed one of these:

https://a.co/d/2og68R2

IP55 rated, dual fan, thermostatically controlled, whisper quiet, super reliable so far over a year later and over 5k towing miles in 7 trips.

I mounted it in the top compartment area, on a couple aluminum struts. The "remote" control I attached in the same place. I turn it on Auto when we start a trip, then it goes off when we get back and store the trailer. It's powered off the fridge circuit, so when the fridge is on, its on.

[tfarny]

Thanks to all, this was very helpful! I know now what to do and I'm glad to be a part of this forum community!

Now for the problem of no hot water in the shower....

[waninae39]

we had the same issue on our Sport 22FB 3 way fridge
my soln was similar to rich jenkins in post # 6

i placesa small muffin fans on the bottom opening and the top opening
use i used a small temp controller to control the fans. get PC type qiet fans

i also placed a switch inside that could switch the fan off ,
when on, the fans would only go on when the temp was high enough

not hard to do, just need to be handy

[DCPAS]

I went with a bigger slower moving 200mm fan. Just installed it after not being happy with a supposedly quiet 120mm version. Can't hear it but I have not tried it on a hot day yet. I figure if I can't hear it, I don't need to add a switch.

https://www.amazon.com/dp/B071SLFBNY...v_ov_lig_dp_it

[PaulBristol]

An absorption refrigerator has two heat streams on the back (outside). The obvious one is the finned radiator. The other is the boiler heat. Both pass up word on the back side.

A fan in the bottom can disrupt the boiler heat. It must be carefully arranged so it does not blow boiler heat away.

A fan near the top removes both streams of heat.

Often heat flow can be improved just by modifying the heat path. It is just a chimney. A smooth, uniform space facilitates a smooth chimney effect.

Sometime builders do not do a good job and take short cuts. A fan does only a little to correct bad installations. See refrigerator installation instructions for best configuration. The exact dimensions and shape matter.